AHS Flashcards

Question

What feature of antibodies provide their uniqueness for binding with a specific pathogen?

Answer 1

Variable region

Answer 2

Constant region

Answer 3

Presentation of pathogen

Answer 4

Bind to antigens on B cells and activate B cells

Answer 5

Plasma cell

Answer 6

When activated B cells switch from igM class to another class

Answer 7

To select and preserve cells with the highest affinity for the antigen to then go on and become memory B cells

Answer 8

Compound – consists of two lens systems Light – uses beam of light to view specimens Light path of a microscope: • The optimal set up for a light microscope is referred to as 'Kohler illumination’. • In this case the iris diaphragm of the lamp, the specimen and the primary image are simultaneously in focus. • The objective forms a magnified primary image of the specimen in the image plane, which is viewed and further magnified by the eyepiece. Bacterial smears Blood smear Histology slides Swabs Fine needle aspirates

Answer 9

Special condenser set-up scatters light causing it to reflect off the specimen at an angle Results in bright specimen on a dark background A dark field microscope is ideal for viewing objects that are unstained, transparent and absorb little or no light. These specimens often have similar refractive indices as their surroundings, making them hard to distinguish with other illumination techniques.

Answer 10

Light waves that are diffracted and shifted in phase by the specimen (termed a phase object) can be transformed by phase contrast into amplitude differences that are observable in the eyepieces Good for observing live organisms as allows visualisation of transparent cells and structures without the use of stains

Answer 11

Hair loss/shedding: | • Atrophied hair follicles

Answer 12

Weight loss/muscle loss • Sarcopenia • Reduction in muscle fibres • Affects ‘normal’ activity

Answer 13

``` Dry, flaky skin: • Sebaceous glands less productive • Skin dries out and flakes (dandruff) ```

Answer 14

Odour: • Reduced immune function • Recurrent secondary skin infections

Answer 15

``` Immune function: • Reduces levels of immune cells • Impaired ability to fight infection & target cancer cells ```

Answer 16

* Cataracts * Iris atrophy * Retinal degeneration

Answer 17

• Degeneration of nerve cells

Answer 18

Muffled/weak bark: • Degeneration of nerve cells in the larynx

Answer 19

• Weaker anal and urinary sphincters • Changes in hormone levels can also affect urinary sphincter

Answer 20

``` Osteoarthritis: • Progressive degeneration of the joint • Inflammatory disorder • Pain and stiffness in joints ```

Answer 21

``` Cognitive disfunction: • Changes in behaviour • Secondary to age-related degeneration of the brain • Canine cognitive dysfunction rating (CCDR) ```

Answer 22

Cardiac failure: • Dilated cardiomyopathy • Valvular disease • Arterial hypertension

Answer 23

``` Diabetes mellitus: • Insufficient insulin production • More common in overweight animals ```

Answer 24

DNA is continually being damaged, mutated and altered | The longer an organism is alive, the greater the chances that a DNA change could lead to disease

Answer 25

Impaired protein homeostasis. Proteostasis involves mechanisms for the stabilization of correctly folded proteins and the degradation of incorrect or unneeded proteins by the proteasome or the lysosome

Answer 26

“stable arrest of the cell cycle coupled to stereotyped phenotypic changes” The accumulation of senescent cells in aged tissues can affect function and cause inflammation

Answer 27

Decline in the regenerative potential of tissues One of the ultimate culprits of tissue and organismal aging Recent promising studies suggest that stem cell rejuvenation may reverse the aging phenotype at the organismal level

Answer 28

Alterations in communications between cells and tissues can have widespread effects Pro-inflammatory status (inflammaging) impacts many organ systems Parallel dysfunction in the immune system can aggravate the ageing status

Answer 29

An accumulation of physical changes over time that render organisms more susceptible to disease and death A progressive loss of physiological integrity, leading to impaired function

Answer 30

cytotoxin that destroys both neutrophilic leukocytes and macrophages.

Answer 31

Some fixed macrophages are resident in tissues and organs (e.g. Liver (Kupffer’s cells), lungs (alveolarmacrophages), CNS (microglia), spleen (splenic macrophages), bone (osteoclasts), placenta (Hofbauer cells) etc)

Answer 32

The initiation of innate immune response relies on the recognition of pathogen-associated molecular patterns by pattern recognition molecules (PRMs), including the cellular pattern recognition receptors and extracellular soluble PRMs.

Answer 33

Damage-associated molecular patterns (DAMPs)[1] are molecules within cells that are a component of the innate immune response released from damaged or dying cells due to trauma or an infection by a pathogen.[2] They are also known as danger-associated molecular patterns, danger signals, and alarmin because they serve as a warning sign for the organism to alert it of any damage or infection to its cells.

Answer 34

detect invaders and activate other cells and processes in innate and adaptive immune system

Answer 35

4 main steps • Chemotaxis & Adherence: -Chemical signals attract phagocytes to microorganism. - Phagocyte attaches to microbial cell surface – facilitated by interaction of PAMPs with PRRs on phagocyte surface • Opsonization: microorganism is coated with serum proteins to facilitate ingestion • Phagocyte forms pseudopods to engulf the microbe – formation of phagosome • Digestion: Phagosome fuses with a lysosome → phagolysosome where microbe is digested • Discharge: Residual body discharges indigestible material from the cell

Answer 36

Eluding contact (capsule) Inhibiting or killing the phagocyte (e.g. organism releases toxin) Protection against intracellular death, e.g. - resistance to killing (e.g. staphylococci produce antioxidants) - inhibition of phagolysosome fusion (e.g. Mycobacterium tuberculosis); - escape into the host cell cytoplasm (e.g. leishmaniasis)

Answer 37

multicelular metazoan parasites • Requires antibody-dependent cellular cytotoxicity (ADCC) Fc receptorson Mo, Eos and neutrophils interact with antibodies coating helminth • Stimulates releaseof toxic chemicals/proteins

Answer 38

Four main signs and symptoms: • Redness • Swelling (oedema) • Pain • Heat Three main functions: • To destroy injurious agent and to remove it/its by-products from body • To limit its effects on the body by confining/walling off the agent • To repair and replace tissue damaged by the injurious agent * Vasodilation & increased permeability of blood vessels * Phagocyte migration & phagocytosis * Tissue repair

Answer 39

Chemokines • Cytokines • Histamines • Prostaglandins • Leukotrienes

Answer 40

Increased permeability allows defensive substances in blood to enter injured area: • Fluid (oedema) • Antimicrobial proteins • Clotting elements Vasodilation also results in redness and heat

Answer 41

* Tachycardia – particularly if any underlying cardiopulmonary disease * ↑ metabolic rate → acidosis * Dehydration * Electrolyte imbalance * Seizures * Delirium & coma * Can be fatal

Answer 42

The complement system, also known as complement cascade, is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. It is part of the innate immune system,[1] which is not adaptable and does not change during an individual's lifetime. The complement system can, however, be recruited and brought into action by antibodies generated by the adaptive immune system.

Answer 43

Interferons are proteins that are part of your natural defenses. They tell your immune system that germs or cancer cells are in your body. And they trigger killer immune cells to fight those invaders. Interferons got their name because they "interfere" with viruses and keep them from multiplying

Answer 44

Antimicrobial peptides (AMPs) are a class of small peptides that widely exist in nature and they are an important part of the innate immune system of different organisms. AMPs have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses.

Answer 45

an allele that produces the same phenotype whether its paired allele is identical or different.

Answer 46

only expressed if the individual has two copies and does not have the dominant allele of that gene.

Answer 47

an individual having two different alleles of a particular gene or genes, and so giving rise to varying offspring.

Answer 48

an individual having two identical alleles of a particular gene or genes and so breeding true for the corresponding characteristic.

Answer 49

An autosome is any of the numbered chromosomes, as opposed to the sex chromosomes.

Answer 50

A sex chromosome is a type of chromosome that participates in sex determination. Humans and most other mammals have two sex chromosomes, the X and the Y

Answer 51

A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.

Answer 52

Gene loci that are closer together are less likely to be separated onto different chromatids during crossing over

Answer 53

the combined effect of all factors (environmental and genetic), that render an animal more or less likely to develop that disorder

Answer 54

Diagnostic tests that use antibodies Tests either: • Detect antibodies in a sample OR • Detect antigens in a sample using antibodies

Answer 55

* Specific portion of pathogen * Protein found on surface of pathogen * Non-self

Answer 56

``` Self • Protein • Immunoglobulins • Designed to “fit” onto specific Ags and so neutralise them • Specific binding sites ``` Ig molecules bind specifically to an antigen and eliminate it

Answer 57

Presence of infection • Looking for pathogen / antigen Evidence of exposure • For diseases where antibodies are created ``` Immunoassays test for or measure: • Presence of antigen • Presence of specific antibodies • Levels / quantities of antibody to determine level of protection, stage of disease (getting worse or better) ```

Answer 58

``` Precipitation Agglutination with latex beads Radio-immunoassays Agar Gel Immunodiffusion (AGID) Complement Fixation (CF) ```

Answer 59

Precipitation reactions are based on the interaction of antibodies and antigens. They are based on two soluble reactants that come together to make one insoluble product, the precipitate. These reactions depend on the formation of lattices (cross-links) when antigen and antibody exist in optimal proportions. Binding of antibodies to the antigen forms precipitate

Answer 60

An antigen and an antibody are placed in separate wells of an agar gel Antigen and antibodies diffuse towards each other A thin white line is formed due to the precipitation of antigen/antibody complex

Answer 61

addition to causing precipitation of soluble molecules and flocculation of molecules in suspension, antibodies can also clump together cells or particles (e.g., antigen-coated latex beads) in a process called agglutination . Agglutination can be used as an indicator of the presence of antibodies against bacteria or red blood cells.

Answer 62

The antibody from the patient serum and the antigen are mixed with fresh complement. Sensitized sheep cells are then added. When the patient antibody is absent, the complement will be able to bind to the antibody-coated sheep cells and cause hemolysis. But when the antibody is present, the antigen-antibody complex binds to the complement, and therefore, no hemolysis will occur. When there is no hemolysis, it indicates a positive reaction.

Answer 63

2 types of ELISA: • Direct test - Antibodies used to test for antigen • Indirect test – Antigens used to test for antibody Can test for: • Bacteria or bacterial toxins • Viruses • Protozoa • Ab to any of these or Ab to parasites, yeasts,

Answer 64

Antibodies used to test for antigen

Answer 65

Antigens used to test for antibody

Answer 66

To detect antigens in cells of a tissue section Antibodies introduced that bind specifically to the antigens in questions in situ in the tissue sample Antigen-antibody complex visualized in different way Immunofluorescense

Answer 67

The basic principle of radioimmunoassay is competitive binding, where a radioactive antigen ("tracer") competes with a non-radioactive antigen for a fixed number of antibody or receptor binding sites. A RIA is a very sensitive in vitro assay technique used to measure concentrations of substances, usually measuring antigen concentrations (for example, hormone levels in blood) by use of antibodies

Answer 68

staining and visualisation through gel electrophoresis (and other methods) The only way to know if a particular sequence of DNA (a gene) is present is to selectively amplify it

Answer 69

* Uses oligonucleotide primers to amplify region of interest (gene) * Cycles of heating and cooling drives each step * Millions of copies can be produced in minutes * Number of copies provides information on presence and/or amount of starting material

Answer 70

denaturation: 94-95C High temperature breaks hydrogen bonds holding base pairs together ‘Melts’ double-stranded DNA revealing bases in specific order Fun fact! The polymerase enzymes needed for this procedure were identified in thermophilic bacteria so they could cope with the high temperatures annealing: 50-56C • At cooler temperatures, complementary bases can bind • Oligonucleotide primers ‘match’ small regions of the target area (gene of interest) • They bind to the matching areas (anneal) Primers must be designed so that one matches the sense strand and the other matches the antisense strand extension/elongation: 74°CC • Synthesis of new complementary DNA strand from 3’ end of primer Only regions where primers bound will be amplified/copied. So it’s really important that they only match the region we’re interested in * In one cycle (denaturation; annealing; extension) we have gone from one copy to two * Cycle is repeated multiple times and product number increases exponentially * Average PCR run is 40 cycles

Answer 71

method by which the amount of the PCR product can be determined, in real-time, and is very useful for investigating gene expression. does not rely on any downstream analysis such as electrophoresis or densitometry and is extremely versatile, enabling multiple PCR targets to be assessed simultaneously fluorescence is measured after each cycle and the intensity of the fluorescent signal reflects the momentary amount of DNA amplicons in the sample at that specific time. In initial cycles the fluorescence is too low to be distinguishable from the background. However, the point at which the fluorescence intensity increases above the detectable level corresponds proportionally to the initial number of template DNA molecules in the sample. This point is called the quantification cycle four distinct phases within the qPCR curve? Lag Exponential Linear and plateau

Answer 72

Uses reverse-transcriptase enzyme to produce double stranded DNA from RNA • This provides template for normal PCR • Can also be incorporated into qPCR = RT-qPCR

Answer 73

* Be collected before the start of antibiotics (where possible) * Be representative of the infection site * Be collected in a sterile manner * Transported properly and quickly

Answer 74

Morphology - Size - Shape - Arrangement - Staining affinity - Spores - Capsule

Answer 75

involves directly staining the bacterial cell with a positively charged dye in order to see bacterial detail, in contrast to negative staining where the bacteria remain unstained against a dark background

Answer 76

Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism. ... One commonly recognizable use of differential staining is the Gram stain.

Answer 77

"Special stains" are processes that generally employ a dye or chemical that has an affinity for the particular tissue component that is to be demonstrated. They allow the presence/or absence of certain cell types, structures and/or microorganisms to be viewed microscopically.

Answer 78

Gram stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria Gram staining differentiates bacteria by the chemical and physical properties of their cell walls. Gram-positive cells have a thick layer of peptidoglycan in the cell wall that retains the primary stain, crystal violet. Gram-negative cells have a thinner peptidoglycan layer that allows the crystal violet to wash out on addition of ethanol. They are stained pink or red by the counterstain,[2] commonly safranin or fuchsine. Lugol's iodine solution is always added after addition of crystal violet to strengthen the bonds of the stain with the cell membrane. method: Crystal violet added to a heat-fixed bacterial smear stains all cells purple (primary stain); After washing, the smear is covered with iodine which forms a purple CV-I complex in the cytoplasm; Washing the slide with alcohol-acetone ( a decolouriser) disrupts the outer LPS layer of G-ve cells and the CV-I complex is washed away through the thin peptidoglycan; these cells are then colourless until counterstained with safranin (pink); Alcohol-acetone does not wash the CV-I complex out of G+ve cells (thicker peptidoglycan), so they remain purple.

Answer 79

Differential stain to distinguish between acid fast and non acid fast cells Initially, carbol fuchsin stains every cell. When they are de-stained with acid-alcohol, only non-acid-fast bacteria get de-stained since they do not have a thick, waxy lipid layer like acid-fast bacteria. When counter stain is applied, non-acid-fast bacteria pick it up and become blue (methylene blue) or green (malachite green) when viewed under the microscope. Acid-fast bacteria retain carbol fuchsin so they appear red

Answer 80

Differential media contain compounds that allow groups of microorganisms to be visually distinguished by the appearance of the colony or the surrounding media, usually on the basis of some biochemical difference between the two groups.

Answer 81

The oxidative-fermentative test determines if certain gram-negative rods metabolize glucose by fermentation or aerobic respiration (oxidatively). During the anaerobic process of fermentation, pyruvate is converted to a variety of mixed acids depending on the type of fermentation. The high concentration of acid produced during fermentation will turn the bromthymol blue indicator in OF media from green to yellow in the presence or absence of oxygen .

Answer 82

The catalase test is primarily used for gram positive bacteria and can be utilized to distinguish Staphylococcus spp. and Micrococcus spp., which are catalase positive from Streptococcus spp. and Enterococcus spp., respectively, which are catalase negative The presence of the catalase enzyme can be demonstrated by adding hydrogen peroxide to the bacterial inoculum, which results in the rapid liberation of oxygen bubbles. The lack of enzyme is demonstrated by the absence of such bubbles.

Answer 83

Some bacteria can utilize citrate as the only carbon source and the citrate test shows if the actual bacterium has this capability. Positive test result: growth in citrate medium or growth with colour change to blue in Simmon's citrate tube. Negative test result: no growth in citrate medium eller growth but no colour change (still green colour) in Simmon's citrate tube. Use The citrate test is used to distinguish between, among others Citrobacter freundii and Escherichia coli.

Answer 84

Some bacteria produce coagulase, which is an enzyme that converts fibrinogen to fibrin, which means that it can coagulate plasma. The ability to produce coagulase is assumed to be associated to the virulence of staphylococci. The test is used to distinguish between coagulase positive and coagulase negative staphylococci. Positive reaction if the plasma coagulates and the coagulate is stable. It must not be dissolved upon stirring. Negative reaction if the plasma does not coagulate or if the coagulate is dissolved again upon stirring. The coagulase test is used to distinguish between Staphylococcus aureus from coagulase negative Staphylococcus spp

Answer 85

Many bacteria have enzymes that break down nucleic acids. The bacteria can then use the resulting nucleotides to build up their own nucleic acids. DNase is such an enzyme, which thus hydrolyzes DNA. Existence of DNase is characteristic for certain species or strains of bacteria and can be used for typing. Presence of DNase can be determined by cultivation on an agar plate, which contains DNA. If the bacterium has DNase and if the bacteria are allowed to grow over night, the DNA will be hydrolyzed into the constituting nucleotides. Diluted hydrochloric acid (HCl) is then poured onto the plate and there will be a clear zone close to the colonies or the streak, because individual nucleotides are soluble in diluted HCl, but not DNA, which precipitates in the rest of the plate. Use The test is useful to distinguish between: Serratia spp. and Enterobacter spp. Staphylococcus aureus (most strains are coagulase positive) and coagulase negative Staphylococcus spp. Moraxella catarrhalis and Neisseria spp.

Answer 86

Some bacteria can hydrolyze hippurate to the amino acid glycine and benzoate by means of the enzyme hippuricase. Glycine can be detected with ninhydrin (2,2-Dihydroxyindane-1,3-dione), which reacts with free amino groups (-NH2) and a blue product is formed. Positive test resultat: Deep blue colour. Negative test result: Pale blue colour. Use The hippurate test is primarely used to distinguish between Campylobacter jejuni (hip+) and Campylobacter coli (hip-) and to distinguish between different streptococci (see figure).The test is also used, in combination with other methods, to type Brachyspira spp.

Answer 87

Some bacteria can metabilize certain sulfur containing compounds under production of hydrogen sulfide (H2S). Hydrogen sulfide is a toxic, flamable and badly smelling gas (smells like rotten eggs). If soluble iron or lead salts (for instance ferric citrate) is used in a so-called H2S-medium, which should also contain sodium thiosulfate (Na2S2O3), they can react with H2S, if present, under formation of black insoluble iron and lead sulfide, respectively. Positive test result: a black precipitate in the medium. Negative test result: no precipitate in the medium. Use The test can be used for differentiation of, among other bacteria, certain Campylobacter spp.

Answer 88

Positive test result: The indole reagent change colour to cerise red. Negative test result: The indole reagent remains pale yellow. Use Confirmation of suspected E. coli-strains. Typing (species determination) of Brachyspira spp. in combination with other tests. Kovac's indole reagent is more sensitive than the indole spot reagent, but it is not recommended for use with anaerobic bacteria. The indole spot reagen is suitable for both aerobic and anaerobe use.

Answer 89

Many bacteria have enzymes which can break down lipids, so-called lipases. Lecithinase, which is also called phospholipase C, is such an enzyme that splits the phospholipid lecithin (= e.g. phosphatidylcholine). Phospholipids, which are charged are usually soluble in water, but one of the products which is formed by the splitting, namely a diglyceride, is not charged and it has two long hydrocarbon chains. It is, therefore, unsoluble in water and this is utilized in the lecithinase test, where bacteria are cultivated on egg yolk agar. Egg yolk contains a lot of lecithin. Method Apply the bacteria in the form of a streak onto the egg yolk agar. Read the plate after 24 h. Positive test result: Precipitation around the streak of bacteria. Negative test result: No precipitation. Can among other things be used to differentiate between certain species within the genus Bacillus.

Answer 90

Some bacteria can ferment glucose to a mixture of the following organic acids: formic acid, acetic acid and lactic acid. This is called mixed acid fermentation and it causes highly decreased pH in the medium. Mixed acid fermentation can, therefore, be detected by addition of the pH indicator methyl red (MR). The test method is sometimes called the MR test. Positive test result: red colour change Negative test result: no colour change. Use Some members of the family Enterobacteriaceae have mixed acid fermentation (see the respective bacterial page), which can be used to differentiate these bacteria.

Answer 91

Bacteria, which have aerobic respiration, often have cytochrome c and a cytochrome c oxidase. The presence of these components can in combination with other methods be used for typing. A commersial test, which contains an artificial electron acceptor (N, N, N', N'-tetramethyl-p-phenylenediamine, see Fig. 1), is often used. This artificial electron acceptor change colour depending upon redox state. Positive test resultat: Dark blue-purple colour change within 10-30 sec. Negative test resultat: No colour change or colour change after more than 30 sec. The oxidase test is used for identification of gram negative bacteria. For instance to identify members of the family Enterobacteriaceae, which are oxidase negative, except members of the genus Plesiomonas (oxidase positive). Members of the family Pseudomonadaceae, and the genera Aeromonas and Campylobacter are oxidase positive.

Answer 92

The purpose of the potassium hydroxide test (KOH test) is to identify gram negative bacteria. KOH dissolves the thin layer of peptidoglycan of the cell walls of gram negative bacteria, but does not affect gram positive cell walls. Disintergration of gram negative cell walls lyses the cell and release its contents, including the DNA. The DNA will make the solution very viscous and the solution will stick to the plastic loop when touched. Gram positive bacteria will not be affected by KOH, because they have thicker peptidoglycan layer in the cell wall. Thus, the cells will not be lysed, the DNA not released and no viscosity will be observed. Positive results: The solution with the bacteria (gram negative) will be viscous Negative results: The solution with the bacteria (gram positive) will not be viscous Use The purpose of the KOH test is to quickly distinguish between gram negative and gram positive bacteria as a complement to Gram staining. The test is not useful for anaerobic bacteria.

Answer 93

Some bacteria have the enzyme urease, which in the presence of H2O converts urea (=carbamide) to NH3 (ammonia) and CO2 (carbondioxide), which forms ammonium carbonate in the presence of water. Positive test result: colour change to pink. Negative test result: no colour change. Klebsiella spp. and Enterobacter spp. has the capacity to perform butanediole fermentation in contrast to Escherichia coli, Salmonella spp. and Shigella spp.

Answer 94

instrument that measures the refractive index of a liquid. The more particles there are in a liquid the more a beam of light will be bent (refracted) as it passes from one medium to another e.g. from air to urine. The result is the formation of a shadow line between the illuminated and dark areas. The result is read from where this shadow line crosses the scale on the refractometer Veterinary clinical refractometers typically have two or three scales (figure 3). The scale used to measure specific gravity is normally found on the righthand side and is typically labelled as U.G. (urine gravity) or S.G. (specific gravity) with a range of 1.000-1.030 or 1.000-1.040 The scale on the left is for serum protein (S.P.). It is used to measure the total protein levels present in a serum or plasma sample. Its units are typically g/dl (g/100ml). These units may also be printed on the lid of the refractometer case. 3 The central scale is the refractive index scale (nD or ND). It can be used with appropriate conversion charts to measure the concentration of many other solutions. It is not present on all clinical refractometers.

Answer 95

The specific gravity of a substance refers to its density divided by (or relative to) the density of water. This is why specific gravity has no units, as it is based on the ratio of one density to another,

Answer 96

When there are multiple potential versions of a gene that are common in a population they are referred to as polymorphisms Polymorphisms can be: • Single nucleotide polymorphisms - differences in a single nucleotide • Deletions (of large or small amounts of DNA) • Copy number variation - chromosomal regions that differ in copy number of certain regions from one to the next • Microsatellites – tandemly repeated short DNA sequences (also called simple sequence repeats or short tandem repeats) which vary by how many repeats are present (there are many other types as well!)

Answer 97

Single nucleotide polymorphisms (SNPs or ‘snips’) are a prevalent type of polymorphism Single base-pair differences between individuals in a population Every genome contains millions of SNPs and they can be used to identify unique features in individuals (e.g. in a paternity test) Some SNPs are the cause of inherited genetic disorders as the polymorphism can result in a faulty, inactive or overactive gene product.

Answer 98

Stained faecal smear – protozoan oocysts and trophozoites • Passive faecal flotation – helminth eggs • Centrifugal flotation – protozoan cysts • Faecal sedimentation – helminth ova (especially trematode ova) • Baermann technique – lungworm larvae in faeces • Vomit flotation – nematode ova

Answer 99

Assessment of blood samples can aid in the detection of certain parasite species. • Direct blood examination – heartworm microfilaria • Modified Knott’s test - heartworm microfilaria • ELISA testing – heartworm antigens and antibodies • Stained blood smear – blood protozoa

Answer 100

• Urine sedimentation – helminth ova

Answer 101

• Skin scrapes/brushings/hair plucks – range of ectoparasites

Answer 102

Direct smear is a very simple technique and can easily be performed in practice. • A small faecal sample (the size of the head of a match) is mixed with a drop of water on a microscope slide and examined with a cover slip under the microscope. • The addition of a drop of lugol’s iodine will aid in the detection of Giardia cysts, which will be stained yellow. • Lung worm larvae such as Crenosoma vulpis and Angiostrongylus vasorum may be detected, and is useful as an initial screen for these parasites, however the low sensitivity (54% to 61%) for the detection of lungworm by this method means it should not be relied on as a sole test if negative.

Answer 103

* Faecal flotation remains the most common method to detect helminth eggs and protozoan cysts and are commonly used in large and small animal faecal analysis. * Flotation techniques allow much larger volumes of faeces to be examined by concentrating ova into small volumes of liquid whilst eliminating debris and allowing direct assessment of parasitic ova. * Principle. * The principle of faecal flotation is based on the specific gravity (SG) differences of the various parts of a faecal sample, i.e. faeces, ova, cysts and debris. * The parasite eggs are lighter (i.e. a lower SG) than the flotation solution and so will float to the surface, whereas the heavier faecal matter (i.e. higher SG) sinks rapidly. * There are several faecal flotation solutions that are commonly used in diagnostic assessment. * Many of these can be made quickly and easily in practice. * Solution utilised should be chosen based on health history of animal and the expected findings. Many different faecal flotation methods are described in the literature, however the Modified McMaster Technique (MMT) is commonly used (see practical sessions for details). • The McMaster technique uses a counting chamber that has two compartments, each with a grid etched onto the upper surface. • When filled with a suspension of faeces in flotation fluid, much of the debris will sink while eggs float to the surface where they can easily be seen and counted. • If a known weight of faeces and a known volume of flotation fluid are used to prepare the suspension, then the number of eggs per gram of faeces can be calculated. • (The MMT may have diagnostic sensitivities as low as 60% for some roundworm ova such as Toxocara species and has poor sensitivity for tapeworm egg detection, however pooling samples over a three day period will increase sensitivity)

Answer 104

Common helminths, protozoan ova and cysts | Sg: 1.2

Answer 105

Common helminth, protozoan ova and cysts (particularly Cryptosporidium oocysts) Sg: 1.2-1.25

Answer 106

Common helminth, protozoan ova and cysts | Sg:1.2-1.33

Answer 107

``` Common helminth (particularly Giardia), protozoan ova and cysts (particularly lungworm larvae) Sg:1.18 ```

Answer 108

Protozoan ova and cysts | Sg:1.32

Answer 109

* Centrifugal flotation increases effectiveness by spinning down faecal debris, allowing the eggs/cysts to float to the surface. * Many research papers have demonstrated that correctly carried out centrifugal flotation results in significantly higher faecal egg counts than using flotation techniques alone.

Answer 110

• While not common, it is possible to identify some nematode ova by evaluating vomit using the same methodology as for faecal flotation. • Likewise, vomit may also be scrutinized under a microscope to locate parasites common to the stomach. • Vomit flotation is useful when parasites, such as Physaloptera species or Ollulanus tricuspis, are suspected in dogs and cats

Answer 111

* The majority of trematode (fluke) eggs are too large and heavy to float reliably in the flotation fluids normally used for nematode eggs, i.e. they have a higher SG, however they do sink rapidly to the bottom of a faecal/water suspension and this is the basis of the faecal sedimentation technique. * Also, some parasites pass free larvae instead of eggs which cannot be detected by routine faecal flotation. * The faecal sedimentation method allows detection of large/heavy eggs and certain free larvae. * This method may also be used for ova that will be distorted or destroyed in the presence of the super saturated salt solutions used in flotation techniques.

Answer 112

• The Baermann technique uses inexpensive equipment, much of which can be reused, for the detection of larvae in faeces. • A rubber hose is attached to a funnel and warm water is placed into the funnel into which the faecal sample, wrapped in gauze is placed. • The warmth of the water activates the larvae in the sample, but they are unable to swim upwards against gravity and as a result will drop through the gauze into the tubing. • This allows collection of the larvae which can then be centrifuged to concentrate the sample. • Addition of Lugol’s iodine before examination kills the larvae, making identification easier. • As well as Angiostrongylus vasorum,the larvae of other lungworms such as Oslerus osleri and Crenosoma vulpis may also be detected using this method.

Answer 113

• Coproantigen ELISA tests are available for the detection of excretory/secretory products from intestinal nematodes. • These tests allow infections to be detected when ova shedding is not occurring and so flotation methods will be ineffective. • ELISA tests also avoid false positive results due to coprophagia. • Testing for Giardia faecal antigens is a highly sensitive and specific test, as are recently commercially launched test kits for intestinal roundworms, whipworms and hookworms. • However, this type of testing indicates the presence of nematodes but gives no indication as to what extent ova shedding is occurring. • Coproantigen testing is being developed for commercial Echinococcus species testing, and PCR testing of faeces is now commercially available.

Answer 114

• All faecal examinations that rely on the visual detection of parasite eggs, cysts, oocysts or larvae in the faeces have some implicit constraints and may not be indicative of the number of worms present – • Inaccuracies in counting can occur. • Microscopic examination of faecal samples cannot detect infestations involving immature worms or those involving only males. • Ideal flotation methods may differ for diagnostic stages of different parasites, but due to time constraints and the desire for standardized protocols, a single method is often used for all faecal testing. • Even though centrifugal flotation has been shown to be superior for parasite recovery from faecal samples, many veterinary practices continue to use a standing, passive flotation. Other, patient specific considerations include - • The daily output of eggs by fertile females is influenced by host-physiological factors such as stress or lactation (increased) or immunity (decreased). • Chemotherapy can affect egg-production, e.g. corticosteroids (increased) or sub-lethal anthelmintic doses (decreased). • Some food-stuffs may affect egg production e.g. tannin-rich forages (decreased). • The concentration of eggs is influenced by the daily volume of faeces being produced by the host, the rate of passage by the ingesta through the intestine, and the distribution of eggs throughout the faecal mass. • Some eggs from different species are indistinguishable (particularly trichostrongylids and strongylids) which complicates clinical interpretation. 25 * Coprophagic behaviour needs to be identified in dogs prior to testing, * False positives can occur if dogs are coprophagic prior to testing. * Strongyle eggs in ruminant and horse faeces will pass through the digestive tract of cats and dogs unchanged, giving the impression that the pet is infected with hookworm. * Similarly, Toxocara cati eggs may be found in dogs that have eaten cat faeces

Answer 115

• Dirofilaria immitis (heartworm) infects cats and dogs and is found in the pulmonary artery of the heart. • (Although D. immitis is not endemic in the UK, increasing numbers of infected rescue dogs are being imported from endemic countries.) • Three methods are used to diagnose heartworm infection in dogs – • Direct Smear – examination of blood on slide. • Modified Knott’s Test (MKT) – detects and allows identification of microfilariae (larval form of D. immitus) of D. immitis via examination of buffy coat layer. • Antigen Test – detects adult female heartworm (ovarian) antigens in a serological assay (ELISA methods such as SNAP Heartworm test available).

Answer 116

– detects and allows identification of microfilariae (larval form of D. immitus) of D. immitis via examination of buffy coat layer.

Answer 117

most sensitive test however false negatives can occur – • In animals with low burden of female heartworms (detects ovarian antigens) or when only male worms are present • If certain types of wormers have been used that lead to the formation of immune complexes that can block detection of the antigen. • Animals on heartworm preventive medication become amicrofilaraemic and so the MKT will be insufficient. • Feline dirofilariasis cannot be reliably diagnosed by microfilaraemia or antigenemia tests, because heartworm numbers are typically too low.

Answer 118

* Urine testing for parasites less relevant for the UK. * There are several parasites restricted to the urinary system, such as the giant kidney worm (Dioctophyma renale) and bladder worm (Pearsonema plica). * Ova may be identified by examining urine sediment samples collected through cystocentesis.

Answer 119

Superficial close examination may reveal the presence of certain ectoparasites (lice, ticks, flies) but further methods are required for microscopic parasites or those that live beneath the surface of the skin.

Answer 120

* Skin scraping is an easy and effective method that can be used to make a definitive diagnosis of ectoparasitic infestation. * The edge of a scalpel blade is gently scraped across the surface of the skin in order to collect material which can then be examined under a microscope, usually in a drop of mineral oil on a slide under low power-magnification. * Addition of 10% potassium hydroxide solution may help to clear debris and allow better visualization. * Some surface living ectoparasites such as Cheyletiella may be found with a superficial scrape, however those that burrow (Sarcoptes) or live in hair follicles (Demodex) will require a deeper scrape (capilliary ooze).

Answer 121

• Finding one mite, egg or deposit of faeces from sarcoptic mites allows a definitive diagnosis. • However, as demodex mites are commensals on several species, the significance of one or two mites is not clear. • False negatives are common with skin scrapes, especially with the deep living forms, and so the absence of a parasite in a sample does not confirm absence on the animal.

Answer 122

• Coat brushings are useful to indicate presence of fleas and Cheyletiella mites. • The simplest approach is to place a sheet of white paper below the animal and rub or comb the fur towards the paper. • Debris removed by this method can indicate fleas through the presence of black, comma- shaped faeces which can be moistened to further confirm presence. • Debris can also be examined with a microscope to identify presence of mites or eggs.

Answer 123

* Tape strips can be useful to indicate the presence of Cheyletiella mites, Trombicula autumnalis (harvest mite) larvae, Otodectes and lice. * Demodex mites may be seen on these samples if infestation is severe. * Clear adhesive tape is applied to several locations and then transferred to a microscope slide for examination.

Answer 124

* Hair plucks can indicate the presence of Demodex mites, Cheyletiella eggs, lice and lice eggs. * Small clumps of hair are plucked and examined under a microscope slide.

Answer 125

• A serological (ELISA) test is available for the diagnosis of sarcoptic mange in dogs. • Serum IgG antibodies against Sarcoptes antigens are measured. • It has been reported that the test has 95-98% reliability and a positive result indicates past or present exposure to Sarcoptes scabiei. • Time to sero-convert to positive is approximately 4 weeks and so false negatives are possible. • Time to sero-convert back to negative varies between individuals but can be several months thus affecting accurate assessment of treatment success.

Answer 126

• Solid agar plate (containing suitable nutrients) • Discs, tablets or strips containing a known concentration of antimicrobial agent • Pure culture of microbe to be tested Measures zone of inhibition to find MIC

Answer 127

The lowest concentration of an antimicrobial that will inhibit visible growth of a microorganism after incubation

Answer 128

1. Dilution methods take a volume of antimicrobial to be tested and create a series of dilutions to produce individual tubes or agar plates with a range of strengths of antimicrobial 2. A small amount of the microbe of interest is then added and incubated 3. The lowest concentration at which there is no visible growth of microbes is identified as the MIC (minimum inhibitory concentration) E.g agar and broth dilution method

Answer 129

Etest (previously known as the Epsilometer test) is a way of determining antimicrobial sensitivity by placing a strip impregnated with antimicrobials onto an agar plate. A strain of bacterium or fungus will not grow near a concentration of antibiotic or antifungal if it is sensitive. For some microbial and antimicrobial combinations, the results can be used to determine a minimum inhibitory concentration (MIC) via where the elliptical meets the strip

Answer 130

* Many antimicrobial resistance genes have been identified in many different microorganisms * Molecular methods allow us to identify if a pathogen in our patient sample possesses that gene and would therefore not be susceptible to that antimicrobial * Offers very rapid, accurate and specific resistance testing * Currently used alongside disc-diffusion AST for comparison

Answer 131

The concentration of antibiotic used to define whether an infection by a particular bacterial strain/isolate is likely to be treatable in a patient

Answer 132

antimicrobial suseptibility testing a widely-used method of evaluating antibiotic resistance and determining patient treatment plans in clinical settings. There are a number of different methods of AST such as agar dilution, broth dilution and disc diffusion assays

Answer 133

comparing the recorded MIC from the AST with the clinical breakpoint MIC Breakpoint MIC divided by measured MIC = efficacy

Answer 134

an organism that lives in or on an organism of another species (its host) and benefits by deriving nutrients at the other's expense:

Answer 135

an organism which supports the adult or sexually reproductive form of a parasite.

Answer 136

an organism that supports the immature or non-reproductive forms of a parasite.

Answer 137

paratenic host a potential or substitute intermediate host that serves until the appropriate definitive host is reached, and in which no development of the parasite occurs; it may or may not be necessary to the completion of the parasite's life cycle.

Answer 138

obligate parasite (obligatory parasite) one that is entirely dependent upon a host for its survival.

Answer 139

an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle.

Answer 140

here are certain vectors where the parasites (germs) are attached to the outside of their body, such as in legs and thus transmit the germs or parasites from one host to another without involving any developmental stages of the parasites in their body.

Answer 141

biological vector an animal vector in whose body the pathogenic organism develops and multiplies before being transmitted to the next host. mechanical vector an animal vector not essential to the life cycle of the parasite.

Answer 142

regularly found among particular people or in a certain area:

Answer 143

exhibiting a high and continued incidence —used chiefly of human diseases hyperendemic malaria

Answer 144

widespread occurrence of an infectious disease in a community at a particular time:

Answer 145

An infectious disease acquired by humans from vertebrate hosts of the causative agents. Examples are rabies and trichinosis.

Answer 146

The transmission of disease from humans to animals. Specifically it refers to diseases that are primary infections of humans but which can be naturally transmitted to animals. Examples include tuberculosis and human metapneumovirus.

Answer 147

A zoonosis that can be passed from humans to other species as well as being passed from another species to a human

Answer 148

refers to pathogens sourced from humans and can include human to non-human animal transmission but also human to human transmission.

Answer 149

A zoonosis that requires more than one vertebrate host (but no invertebrate) for completion of the life cycle

Answer 150

A zoonosis that requires both a vertebrate and an invertebrate host for completion of its life cycle; for example, the arbovirus infections of humans and other vertebrates

Answer 151

A zoonosis, the agent of which requires both a vertebrate host and a nonanimal (food, soil, plant) reservoir or developmental site for completion of its life cycle

Answer 152

``` Compete for nutrients Depress appetite Damage skin or internal organs Diarrhoea Liver failure Respiratory problems Increase chances of secondary infections Stimulate immune system so that the animal is more susceptible to disease ```

Answer 153

``` egg l1- free living/ in intermediate host l2- free living/ in intermediate host l3- free livivng in intermediate host- infective stage! l4- within host l5- within host adult reproduction- repeat ``` any unsegmented worm of the phylum Nematoda, having an elongated, cylindrical body; a roundworm. hypoboisis

Answer 154

A stage of parasite larval dormancy where nematode parasite larvae escape harsh environmental conditions by remaining in the wall of the abomasums. Inhibited development stage with mass emergence = longer PPP No inhibited stage = shorter PPP Environmental or external stimulus at free living stage? Mass emergence Examples: Toxocara canis Cyathostomins- small red-worms Teladorsagia

Answer 155

Adult (within definitive host, e.g dog)- gravid proglottids shed Embryophore (in environment)- Ingested by intermediate host Oncosphere (within intermediate host, e.g sheep)- Breaks through gut wall of intermediate host and travels to site to form a … Metacestode (cyst within intermediate host)- Remains within intermediate host until it is ingested by definitive host ndirect lifecycle Hermaphrodites Reliant on host – no free living stage ``` No mouth / anus – absorb pre-digested nutrients through tegument a parasitic flatworm of the class Cestoda, which comprises the tapeworms ``` Taenia saginata, T.solium, T. Ovis, T.multiceps Echinococcus multilocularis, E. granulosus

Answer 156

Eggs-Passed in faeces onto pasture Miracidium -Miracidium hatches Within intermediate host-Develop to sporocyst, rediae and cercariae Leave intermediate host Cercariae Metacercariae- Ingested by grazing animals Lifecycle – 5 months PPP – 3 months Liver and stomach flukes Indirect lifecycle - snails Hermaphrodites Paedogenesis - production of many new individuals from a single larval form Any of numerous parasitic flatworms of the class Trematoda, having a thick outer cuticle and one or more suckers or hooks for attaching to host tissue.

Answer 157

single celled organisms Unsporolated oocyst-Nucleus divides - sporocysts Sporolated oocyst (infective)- Ingested – liberation of sporocysts and sporozoites within them… Sporozoites-Penetrate gut wall cells and reproduce asexually… 1st generation merozoites-Gut cells burst when full of 1st gen merozoites… 2nd generation merozoites-Invade more gut cells…Gut cells burst when full of 2nd gen merozoites… Male / female -Fuse = oocysts! Cryptosporidium Sarcocystidae (Toxoplasma, Neospora) Babesiidae (Babesia)

Answer 158

``` Faeco-oral Grazing, bedding, coat, Fungi Intermediate host Paratenic hosts ```

Answer 159

Time taken from ingestion of eggs/ larvae/ cysts to eggs being present in faeces

Answer 160

``` Arachnids: Mites Ticks 2. Insects: Flies Lice Fleas ```

Answer 161

egg larvae nymph adult

Answer 162

Gravid female lays eggs Eggs hatch - larvae- 12 hours Larvae feed, grow and moult - maggots-Moult 3 times in 3-10 days Maggots drop to ground and pupate-- Pupate for 3 -7 days (may overwinter)

Answer 163

Irritation / annoyance Damage to skin / hide / fleece Bites / wounds (painful!) and possibly anaemia if blood sucking Disease transmission – vectors and 2ndry bacterial infections Allergic reactions to saliva / faeces of ectoparasites Myiasis

Answer 164

Need to know: Which parasites are present, any resistance? Perform faecal egg counts Times of year those parasites cause problems Best time to treat against them or use management to avoid them e.g. Nematodirus, fluke, midges, Which management strategies apply Which chemicals are effective against the parasites that are present

Answer 165

Fleas are wingless insects with laterally compressed bodies. They have six legs that are well adapted for jumping. Two of the most common companion animal fleas are - Ctenocephalides felis (cat flea) - the cat flea is the most common in the UK and infests the cat, dog, rabbits, ferrets, small rodents and man. ``` Ctenocephalides canis (dog flea) found on some dogs in the UK and most common flea on dogs in Ireland. Diagnosis of fleas. ``` treatment targets: Kill the adult flea on the host. Kill the developmental stages in the environment.

Answer 166

Pulex irritans

Answer 167

Spilopsyllus cuniculi

Answer 168

Ceratophyllus gallinae

Answer 169

Xenopyslla cheopis

Answer 170

Ctenocephalides felis

Answer 171

ctenosephalides canis

Answer 172

Besides the direct effects resulting from blood feeding, Ctenocephalides species are important as vectors for a wide range of pathogens, many of which are zoonotic, for example - Yersinia pestis (plague), Rickettsia typhi (flea borne typhus in humans), Rickettsia felis (flea borne spotted fever in humans), Rickettsia conorii (boutonneuse fever in humans), Bartonella henselae (cat-scratch disease in humans) Fleas also act as intermediate hosts for cysticercoid larvae of Dipylidium caninum tapeworms.

Answer 173

Lice are small wingless insects which can occur in large numbers on many companion animal species including dogs, cats, guinea-pigs and rabbits. Lice are generally host-specific There are two main types of louse - sucking and chewing. The “sucking lice” have a pointed head with a piercing proboscis, and feed regularly on blood. Linognathus setosus (dog). The “chewing lice” have a broad head bearing strong chewing mouth parts and feed on epidermal scales, scurf and wool. ``` Trichodectes canis (dog). Felicola subrostratus (cat). Significance of lice infestation - ``` Re-infestation can best be prevented by ensuring that treatment of the host is effective. As lice do not live well off the host, transmission is usually by direct contact. Several products available, including spot-ons.

Answer 174

Linognathus setosus (dog).

Answer 175

``` Trichodectes canis (dog). Felicola subrostratus (cat) ```

Answer 176

Haemodipsus ventricosus.

Answer 177

Ticks are arachnids. They have, as adults, eight legs and are flattened dorsoventrally with a hard shield on the back. The ticks most commonly found on dogs and cats in the UK belong to the genus Ixodes (I. ricinus and I. hexagonus are the most common, but I. canisuga and occasionally I. frontalis and I.trianguliceps have been seen). They have no wings. I. ricinus is a three-host tick and the life cycle requires three years. The main importance of ticks is their role as vectors of pathogenic agents which cause a range of tick-borne diseases. Babesia spp (babesiosisi)., Borrelia burgdorferi (lyme) sensu lato, Hepatozoon canis, Acanthocheilonema (Dipetalonema) spp., Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, A. platys, Rickettsia spp., flaviviruses and others can all be transmitted by ticks. Removing ticks inappropriately can lead to tick granulomas. Physical removal – tick hook. Several products available including collars and spot-on preparations dont lay eggs on host

Answer 178

The entire life cycle of the mite takes place on the animal or within its skin, but many of the stages can remain infective for several days off the animal.

Answer 179

(ear mites). These are commonly found in the dog and cat

Answer 180

Often referred to as fur mites. walking dandrus Cheyletiella yasguri most common in the dog and Cheyletiella blakei in cats. The entire life cycle takes approximately three weeks and is spent on the host, although female mites can survive for up to ten days in the environment. Transfer from host to host occurs readily and rapidly between animals in close contact and cheyletiellosis is common in kennels with young and weak animals being more susceptible.

Answer 181

Demodex canis in dogs and Demodex cati in cats. Demodex lives in hair follicles and sebaceous glands Diagnosed via deep skin scrapings or hair plucks

Answer 182

Notoedres cati Occurs mainly in cats. Although infestation with N. cati has been reported from all European countries it is rare in some and tends to be local in distribution in others.

Answer 183

Sarcoptes scabiei Sarcoptic mange mites are small, round parasites (up to 0.4 mm in diameter) which spend their entire life cycle on the host, so transmission is mainly through close contact. They burrow in the superficial layers of the skin. Transmission to new hosts from infested individuals is by direct or indirect contact, most likely by transfer of larvae from the skin surface - It is known that S. scabiei can survive for several weeks off the host.

Answer 184

(Neotrombicula (Trombicula) autumnalis) responsible for the condition known as trombiculosis. Uncommon and characterised by their seasonal nature (July and August). Control – spot-on preparations available although control is difficult due to the fact that reinfestations are frequent in animals exposed to these mites. Only the larvae are parasitic and they do not transfer from animal to animal. Harvest mites are resistant to adverse climatic conditions and female mites can live for more than 1 year.

Answer 185

Flattened, tape-like segmented body. Each segment is self-contained, containing one or two sets of male and female reproductive organs. The end segment is released from the tip of the tail and can pass out in the faeces. This contaminates the areas where the animal defaecates. Tapeworms have an indirect lifecycle requiring an intermediate host where the larval stages develop. Larval forms usually encyst within the tissues of the intermediate hosts and primary control measures therefore include preventing exposure to intermediate hosts, where possible.

Answer 186

Primary host is the dog or cat. Intermediate host is the flea. The adult tapeworms live in the intestines, eggs develop in the segments (proglottids). segments are shed from the tail of the tapeworm and are then passed out with the faeces into the environment. The segments (proglottids) can often be seen around the affected animal’s perineal/anus area - often described by owners as “grains of rice”. Eggs ingested by flea larva (intermediate host) and cyst develops in the flea body cavity containing developing forms of the tapeworm. Flea ingested by primary host.

Answer 187

Primary host - most commonly cats but also dogs. Intermediate host – birds, small mammals etc (prey of hunting cat). The adult tapeworm is found in the small intestine of the final host, segments and eggs reach the exterior in the faeces, egg is ingested by the intermediate host. Once in the intermediate host, egg hatches and the embryo moves into the blood, lymph or (in invertebrates) the body cavity. The embryo then moves to its predilection site in the host, which can be lungs, brain or muscle. Once in its predilection site the embryo develops into its larval stage (cyst). Intermediate host ingested by primary host. Taenia taeniaeformis, the species that occurs in cats, uses rodents as intermediate hosts and dogs or cats are infected when they eat tissues or viscera of infected hosts. Usually well tolerated in dogs and cats, potentially some anal irritation due to motile segments.

Answer 188

Echinococcus granulosus Primary host – dog. Intermediate host – the usual intermediate host is sheep however, any mammal in contact with dogs can become an intermediate host, including man (zoonosis). The adult tapeworm is found in the gut of the dog, contamination of the environment occurs through the dog defaecating (eggs can survive in the environment for about a year). Eggs are ingested by the intermediate host and encyst within the body (hydatid disease). Cysts develops in lung, liver and body cavity containing developing forms of the tapeworm (hydatid disease). Dog becomes infected by eating the intermediate host.

Answer 189

Zoonotic tapeworm causing alveolar echinococcosis in humans that results in high fatality. The definitive hosts are canids, mainly the red fox although domestic carnivores (dogs and to a lesser extent cats) can also be infected with the parasite. Voles act as intermediate hosts. The mandatory tapeworm treatment within the PETs scheme prior to entry into the UK is designed to prevent its entry.

Answer 190

Roundworms have no segments and tend to be of a whitish or pinkish brown colour. Prolific egg-layers and just a few worms can produce large numbers of eggs. Toxocara spp. eggs can survive in the environment for months or even years. Toxocara canis in zoonotic roundworm in dogs Toxocara cati in zoonotic roundworm in cats Toxascaris leonina - zoonotic roundworm in cats and dogs Dogs and cats can become infected from a number of sources including - Picking worm eggs up from grass or soil in public places. By ingesting a paratenic host. Pregnant bitches can pass infection to their puppies both in utero and via the milk. Pregnant queens can pass infection to their kittens via the milk (but not in utero).

Answer 191

Angiostrongylus vasorum A. vasorum is now endemic in much of the UK. Slugs and snails act as intermediate hosts, although dogs may also acquire infection through ingestion of frogs and other amphibians acting as paratenic hosts. nematode l1 eaten by intermediate host l1 deveops to l3 in intermediate host

Answer 192

Hookworms are small nematodes characterised by large mouthparts that are at an angle to the rest of the worm, hence the common name. There are three species of significance in Europe – Ancylostoma caninum, Bunostomum spp Ancylostoma tubaeforme Uncinaria stenocephala (most common in UK). Life cycle - All hookworms demonstrate a direct life cycle - eggs passed in the faeces, once ingested develop within 2-3 weeks to adult worms. Ancylostoma spp. larvae are capable of penetrating skin and thus making their way to the intestine. Control – prompt removal of faeces and disposal will help to prevent larvae developing on grass, however regular worming to control Toxocara spp. will usually also control hookworms.

Answer 193

Eggs are passed in the faeces of infected dogs and can lead to considerable and persistent contamination of the environment. First stage larva protected by the egg shell and can survive in the environment for years. Dogs are infected when they eat eggs containing infective larvae - pre-patent period is 2 - 3 months and infected dogs may continue to shed eggs for up to a year. Control - depends on removing dogs where possible from the contaminated environment and repeated anthelmintic treatment (regular worming to control Toxocara spp. will also control hookworms so long as a treatment with an appropriate spectrum of activity is selected.) Prompt removal of faeces and disposal will help to prevent eggs developing in the environment.

Answer 194

production of many new individuals from a single larval form

Answer 195

Anthelmintics - various applied via oral, pour-ons, spot-ons,

Answer 196

Oral praziquantel or double dose pyrantel applied orally

Answer 197

Triclabendazole, Closantel, Nitroxynil, Albendazole, Oxyclozanide applied oraly

Answer 198

Sulphonamides applied orally

Answer 199

``` Dipping Showers Weekly bathing with specific product Spot ons and Pour ons Injectables Isolate affected animals Remove eggs – comb, insecticide Dress lesions with appropriate insecticide Tailing, dagging Endoparasite control Remove manure from grazing and housing areas to remove insects Manure heap fermentation Temperature kills eggs and larvae ``` Remove breeding sites such as stagnant water or remove animals from breeding area E.g. Tick survival dependent on tick’s requirement for water Must have relative humidity greater than 90% Common in wetter, marshy areas E.g. Mosquitoes eggs laid in standing water Larvae live in standing water Insecticide or repellent impregnated ear tags, tail bands and halters Screens to prevent insect access to housing Electrocution grids to kill insects within housing Fans to affect flight Wash and treat all bedding, grooming tools, equipment, rugs, Or leave unused for 3 weeks lice control: Cattle - in cattle, a range of pour-on or spot-on synthetic pyrethroids, e.g. permethrin, are available for louse control, also pour-on and injectable macrocyclic lactones (MLs), e.g. ivermectin also commonly used. Most insecticides registered for use on cattle are not active against louse eggs and so a second treatment may be required. The timing and frequency of treatments depends on individual circumstances, however in many cases treatment in late autumn or early winter will give adequate control of cattle lice, often when cattle are housed for the winter. Sheep - treatment of chewing lice in sheep is by organophosphate (OP) dip or by topical synthetic pyrethroids. Pour-on products should be avoided in fully fleeced sheep, as this results in a less effective treatment and increases the risk of resistance.

Answer 200

Fasciola hepatica (cattle) Dicrocelium dendriticum (sheep) Body system affected- alimentary: liver Highly pathogenic Acute-Sudden death or dullness, anaemia, dyspnoea, ascites and abdominal pain Subacute-Rapid weight loss, anaemia, submandibular oedema and ascites in some cases. Drugs (resistance seen) Move onto lower risk pasture infective strategy Galba truncatula snail -Wet pasture

Answer 201

Paramphistomium Calicophoron daubneyi Body system affected- alimentary: rumen Life cycle-similar to liver fluke, however once in the definitive host: After excysting in the small intestine, the tiny immature rumen fluke migrate ‘upstream’ and settle in the rumen and reticulum, where they mature and lay eggs. Infective strategy: Galba truncatula snail Pathogenesis: generic Diagnostic methods: faecal egg count (FEC) by sedimentation, PM, meat inspection Treatment options-advice not to treat, limited drugs available Emerging issues: only identified in the UK last 20 years,

Answer 202

``` Ostertagia ostertagi (abomasal), Telorsagia cercumsincta (abomasal), Haemonchus spp (abomasal), Dictyocaulus spp (respiratory &alimentary), Nematodirus spp (small intestine), Trichostrongylus spp ``` Life cycle-direct Infective strategy –need infective pastures, critical temperatures, periparturient rise in production, hypobiosis Pathogenicity varies genera and species, numbers of nematodes age (maturity) nutritional status body condition Diagnostic methods: FWEC but will give false negative in early stages of disease due to lack of mature egg producing parasites. Treatment options-drugs, grazing management control, lung worm vaccine

Answer 203

Cyathostomins, Chabertia (colon), Oesophagostomum (colon) Body system affected- alimentary Life cycle-simple, non migratory Pathogenesis-no clinical significance unless concurrent disease Diagnostic methods-FWEC Treatment options-drugs

Answer 204

Ascaris suum, Trichinella spp, Body system affected- small intestine, liver, lung Life cycle-direct Infective strategy-infective L3 and arrested development. Migratory or non-migratory Pathogenesis-Milk spot liver in pigs Diagnostic methods-PM, meat inspection Treatment options-drugs, hygiene Emerging issues-increasing numbers of outdoor sows so more difficulty in eliminating them from a premises.

Answer 205

Causes Diarrhoea in calves and lambs alimentary-small intestine in sheep, caecum and colon in cattle Life cycle:direct, highly host specific Causes diarrhoea in calves under a year old and lambs 1-2months old -each host can be infected by a number of different Eimeria spp Reside in the small intestine in sheep, Caesium and colon in cattle -Infective strategy:lambs infected by chronically infected adults which shed oocysts, the lambs then produce large numbers of oocysts to infect others. The sporulated infective oocyst contains 4 sporocysts each containing 2 sporozoites (8sporozoites/sporulated oocyst) Pathogenesis: 11 species infect sheep but only 3 are pathogenic, 13 infect cattle but only 2 are pathogenic Diagnostic methods: Faecal worm egg counts for coccidial oocysts Treatment options: Drugs to treat and prevention Environmental action Feed off the floor Improve hygiene Lower stress levels Low numbers in FWEC can be normal ‘background’ levels, only concerned when get high numbers over 5000 per gram In feed medication Oral drenches Need to get some exposure to gain immunity

Answer 206

Causes diarrhoea in young calves and lambs Body system:small intestine Life cycle:direct Infective strategy: Pathogenesis: as the oocysts grow they disrupt the brush border, decreasing absorption of fluids from the lumen Causes diarrhoea in young calves and lambs, 2-4weeks old it develops at the junction between the micro-villous brush border and the cytoplasm gut epithelial cells. It produces very small (~4mm) sporulated oocysts which either initiate another cycle of asexual reproduction in the same host or are shed from the body via the faeces Diagnostic methods: SNAP test for crypto, faecal smear after Giemsa stain; Identification of organism in stained gut sections of post mortem Treatment options: Drugs to treat and prevention Environmental action Control other diarrhoea pathogens Colostrum management Emerging issues:important cause of food poisoning in humans from contaminated water sources or meat. High risk pathogen for immunosuppressed people As well as causing disease in its own right, Crypto is an opportunistic pathogen and loves to tag onto the back of rotavirus infections when the intestinal lumen is already damaged, further damaging the intestine causing much more severe diarrhoea Hygiene, cleaning, drying and disinfecting equipment used to feed and house young Good colostrum management

Answer 207

Usually non pathogenic but in high levels Causes enteritis in piglets affects the small intestine causing diarrhoea, dehydration, and loss of electrolytes, perhaps death Life cycle:direct Treatment options: Drugs to treat and prevention Environmental hygiene confinement-raised, one to three week old, nursing piglets and is less frequent and severe in older recently weaned piglets.

Answer 208

Causes abortion and meat condemnation in sheep and cattle Causes abortion & congenital abnormalities in humans Body system affected- alimentary and reproductive Life cycle: indirect, specific pairings of intermediate and definitive hosts Over 250 types: Species-specific prey-predator life cycles After ingestion of sporocysts by a suitable intermediate host, sporozoites are liberated and initiate development of schizonts in vascular endothelia of mesenteric arterioles and lymph nodes. A second generation of endothelial schizonts is produced in capillaries from several organs. Merozoites released from these schizonts invade the muscle fibers and develop into the typical sarcocysts Natural infections are usually asymptomatic. No effective treatments prevent ingestion of prey carcasses or raw tissues by omnivorous or carnivorous animals Some drugs are used abroad as a prevention but are not licensed in the UK Effective cooking or freezing kills the parasite in meat.

Answer 209

Body system affected- alimentary and reproductive Life cycle: indirect, facultative heteroxenous Infective strategy: capable of developing in almost any cell type Clinical signs: Barren to tup, abortion, mummification stillbirth (occasionally one live lamb born with a dead lamb) birth of weak lambs White focal necrosis on the placenta Definitive host is the adolescent naive cat who is infected by eating infected rodents, produce oocysts in their faeces before becoming immune. Toxoplasmosis is caused by toxoplasma oocysts picked up from feed or hay, or off pasture that has been contaminated by cat faeces. These oocysts are very resilient and can survive for very long periods in feed or on pasture Once a ewe has been infected, she soon becomes immune and is unlikely to show signs of the disease in subsequent years. It is only when an infection is picked up for the first time during pregnancy that problems occur. The stage at which an infection is picked up during pregnancy will determine the outcome as there is an approximate six week lag period between infection and onset of clinical signs: First 60 days – foetus absorbed and the ewe appears barren. 60 – 120 days – abortion in late pregnancy with mummified foetuses, stillbirths or weak and sickly lambs that often die. There are five main syndromes of abortion in sheep – Barren to tup, abortion, mummification (particularly common with toxoplasmosis), stillbirth (occasionally one live lamb born with a dead lamb) birth of weak lambs which fail to suckle properly and often succumb to disease in young life. It is however common to have many or all of these syndromes on a farm at the same time. A clinical sign which is characteristic of toxoplasmosis abortion is the development of small white areas in the cotyledons (buttons) of the placenta. These are caused by focal necrosis (death of cells) in areas of the placenta due to damage caused by multiplication of the Toxoplasma organism.

Answer 210

Body system affected- alimentary and reproductive Life cycle: indirect – canids definitive host Infective strategy – cattle ingest infected canid faeces Diagnostic methods: PM calf Maternal antibodies Treatment options: none, test and cull or don’t breed replacement heifers! Causes over 10% of the UK abortion. Disease and the risk of abortion can be vertically transferred transplacentally from mother to daughter Cattle ingest infected faeces Transmission Dogs are definitive hosts of N caninum and are capable of shedding oocysts in feces after eating tissues of infected animals.. Neospora oocysts have an impervious shell that enables survival in soil and water for prolonged periods after canine feces have decomposed. Intermediate hosts such as cattle become infected by ingesting oocysts. Cattle do not produce oocysts and thus do not transmit infections horizontally to other cattle, but latent infection may endure permanently in their tissues and is transmitted to canids by carnivorism.

Answer 211

alimentary and reproductive Life cycle: indirect via Ixodes ricinus Pathogenesis- lyses red blood cells Diagnosis: Clinical signs: a sudden fever, diarrhoea followed by constipation, red urine (caused by the haemoglobin pigment from the burst red blood cells), anaemia (with rapid pulse, fast breathing and pale membranes), milk drop, depression and weakness, and abortion of pregnant Recent movement to pastures known to harbour ticks Blood smears can show up the parasite Treatment options Mild cases may recover without treatment. Drugs available for treatment and prevention Vaccines available abroad Tick control Babesia divergens. The disease is spread between cattle by ticks (Ixodes ricinus in the UK). The babesia is injected into the bloodstream by the tick and then invades the red blood cells and begins dividing, eventually rupturing the cell. Clinical signs begin around 2 weeks after infection Diagnosis: clinical signs Recent movement to pastures known to harbour ticks Blood smears can show up the parasite

Answer 212

Body system affected- reproductive infertility caused by embryonic death results in repeat breeding pyometra, endometritis, or a mummified fetus Life cycle-direct, found in the genital tracts of cattle Infective strategy- males transferring it Pathogenesis: The parasite interacts with bacteria that normally reside in the intestinal tract by adhering to the intestinal epithelium of the host Diagnostic methods- Focus on bulls: Repeated culture (single test identify 90%–95%), PCR isolation Swab vaginal discharge/mucus Treatment options-drugs, herd culling. Biosecurity, vaccines When cows are bred naturally by an infected bull, 30%–90% become infected, suggesting that strain differences exist

Answer 213

``` Body system affected- alimentary Life cycle-direct Pathogenesis-diarrhoea Diagnostic methods-FWEC Treatment options-drugs, improved hygiene Emerging issues-zoonosis Faeco oral transmission Significant human pathogen in developing countries ```

Answer 214

Cheyletiella is a surface-dwelling mite, so superficial skin scrapes should be performed. No capillary ooze is necessary. Superficial scrapings can also be used to diagnose ectopic Otodectes infestation, where mites are living outside the ear canals.

Answer 215

Dermacentor variabilis is a 3-host tick, targeting smaller mammals as a larva and nymph and larger mammals as an adult. Although it is normally found on dogs, this tick will readily attack larger animals, such as cattle, horses, and even humans.

Answer 216

Trichodectes canis is a chewing louse of dogs. It is very host-specific and cannot infest any other species than the dog. It can have serious effects in puppies and older, debilitated animals. T. canis can also act as an intermediate for the tapeworm Dipylidium caninum

Answer 217

Trichodectes scalaris

Answer 218

Ctenocephalides canis can act as intermediate hosts for parasitic worms including the double-pored tapeworm, Dipylidium caninum, and the nematode, Acanthocheilonema reconditum

Answer 219

``` Cheyletiella parasitovorax Listrophorus gibbus Psoroptes cuniculi Demodex cuniculi Sarcoptes scabiei var cuniculi Notoedres cati var cuniculi Trombicula autumnalis ```

Answer 220

Spilopsyllus cuniculi Rabbit flea Most commonly seen on wild rabbits Important vector for myxomatosis Ctenocephalides felis/canis Cat/Dog flea more commonly found on pets ``` Clinical signs: Pruritus, poor coat May be clinically normal Treatment of rabbit, in contacts and environment Observation of flea dirt Microscopic examination of whole fleas ```

Answer 221

``` Haemodipsus ventricosus Sucking louse Affects wild rabbits – rare in pets Clinical Signs: Pruritus, erythema, papules, alopecia, rarely anaemia May act as a vector for tularaemia ``` Diagnosis: Microscopic visualisation of lice and eggs

Answer 222

Fly Strike – usually Lucilia spp. (Greenbottles) Summer months Usually primary but with underlying cause Eggs can hatch within 12 hours to L1 (non pathogenic) Within 3 days L1  L2 & L3 – cause tissue damage Prevention (Cyromazine) Larval Cuterebra spp can cause subcutaneous infections aberrant intracranial migration  neurological signs Diagnosis: Visible with naked eye

Answer 223

``` Continental rabbit tick Affects wild rabbits – rare in pets C an be transmitted from other household pets Clinical Signs: Can cause anaemia in large numbers May act as a vector for myxomatosis, papillomatosis & tularaemia Diagnosis: Visible with naked eye Microscopic identification ```

Answer 224

``` Nematodes Passalurus ambiguus Cestodes Taenia serialis Taenia pisiformis Echinococcus granulosus Cittotaenia spp Protozoa Eimeria spp Toxoplasma gondii Encephalitozoon cuniculi ```

Answer 225

``` Oxyurid worm ‘pinworm’ Found in caecum and large intestine Adult worms measure 5-10mm Usually non pathogenic More common in wild rabbit populations Heavy infections may cause perianal pruritus in kits May have a role in caecal mixing Transmission between infected rabbits Direct life cycle Coprophagia  spread and reinfection common ```

Answer 226

16 species of Eimeria which affect rabbits Intestinal and Hepatic disease Variable pathogenicity and predilection site Young rabbits most susceptible No cross immunity across species Oocysts can persist for years in the environment Not destroyed by common disinfectants or high temperatures

Answer 227

Obligate Intracellular protozoal parasite Widespread in rabbit population (52% seroprevalence) ! Zoonotic Potentially life-threatening infection in immunocompromised humans Infective spores shed in the urine Remain viable in environment in extreme conditions Infection via ingestion of spores or vertical transmission Parasite primarily attacks CNS, kidney and eye Clinical signs Neurological Head tilt, hindlimb weakness, paralysis, tremors, nystagmus, convulsions and urinary incontinence Ocular Cataracts and lens induced uveitis Renal failure Diagnosis challenging Post mortem examination IgM, IgG Serum antibody titres Urine/CSF PCR High prevalence makes prevention very difficult Good hygiene practicesTreatment (Fenbendazole) not without risk

Answer 228

``` Dermanyssus gallinae Free‐living mite living in housing Breeds off the host Only feeds (blood) at night Can be challenging to diagnose Primarily poultry parasite but all species susceptibleHeavy numbers cause: Anaemia Debility Intense irritation Death in young/small birds ! Zoonotic potential Very Challenging to treat Easily seen with naked eye Often need to set environmental ‘traps’ Spots on eggs ```

Answer 229

``` Mites Trixacarus caviae Demodex caviae Chiridiscoides caviae Lice Gliricola porcelli Gyropus ovalis Trimenopon hispidum Fleas/Ticks Rare ```

Answer 230

Radfordia ensifera | Rat fur mite

Answer 231

``` Mites Sarcoptes scabei Otodectes cynotis Lynxacarus mustelae Demodex spp Ticks Fleas Ctenocephalides spp Pulex irritans Myiasis ```

Answer 232

Ctenocephalides felis, C. canis, Pulex irritans Mild to intense pruritus – usually around neck Flea bite hypersensitivity reported

Answer 233

``` Ixodes ricinus Common in hunting and stray ferrets Rare in pet ferrets Lyme disease not reported Can lead to anaemia in heavy burdens ```

Answer 234

Dermanyssus spp (Red Mite) Ornithonyssus sylvarium (Northern Fowl Mite) Knemidocoptes (Cnemidoptes) mutans, K, pilae Sternostoma tracheacolum Various Feather mites – host specific

Answer 235

``` Protozoa Trichomonads Coccidia Giardia/ flagellates Nematodes Non pathogenic gizzard worms Capillaria Serratospiculum Syngamus trachea Haemoparasites ```

Answer 236

``` Mites are the most common Ophionyssus natricis (Snake Mite) Trombiculid mites (chiggers) NB may be involved in spread of disease Ticks – rare in captive bred reptiles Myiasis Leeches Lice – extremely rare ```

Answer 237

Filarial worms are nematodes infecting the connective tissues and vascular system of dogs and cats. Mosquitoes, but also fleas and ticks, act as vectors for the different species. microfilariae are released by female worms into the blood stream where they become available to blood-sucking mosquitoes. Microfilariae develop to the infective stage (L3) and are transmitted via saliva during feeding. Larvae undertake an extensive migration within the canine host to reach the pulmonary arteries and the right heart and here they develop into the adult stages and mate. In dogs, adult worms have a lifespan of up to seven years (although survival in cats is shorter), and microfilariae can survive between 2–18 months in the bloodstream. Adult worms are found between subcutaneous and deep connective tissue layers in most parts of the body and adults can live for several years.

Answer 238

Endemic areas to non-endemic areas travel - dogs should be examined for dirofilarial infections, treated against adult heartworms and cleared of microfilariae. Furthermore, animals with unknown history should receive prophylactic treatment for two months to kill potential migrating L3–L4 and be tested for circulating antigens and microfilariae six and twelve months later. Non-endemic area to endemic area travel – animals should be protected against adult filarial infections by receiving treatment within 30 days of arriving in the risk areas with macrocyclic lactone drugs. For pets spending no more than one month in endemic areas, a single treatment, usually administered soon after returning home, is sufficient to assure complete protection. In the case of longer visits, a monthly regimen should be administered with the first treatment being given within 30 days of entering the risk area and the last within one month of leaving

Answer 239

Babesia canis is a parasite that infects red blood cells (rbc) leading to destruction of the rbcs and consequentally, potential anaemia. Transmitted by several types of tick. The two main tick vector species for babesiosis, Dermacentor reticulatus and Rhipicephalus sanguineus (brown dog tick) are present in the UK but are uncommon. The UK had been previously considered free of babesiosis despite the presence of its vector, D. reticulatus. However, the increase in animal movement across borders in recent years increased susceptibility to this pathogen establishing itself in the UK Female ticks generally require a period of initial feeding of approximately 24–48 hours before Babesia sporozoites are available for transmission within their saliva to the dog. Sporozoites infect erythrocytes, differentiate into merozoites and divide by binary fission eventually causing cell lysis. In male ticks, transmission may be more rapid as they repeatedly feed taking only small amounts of blood, and they perform co-feeding with females and possibly feed from several different hosts.

Answer 240

ESCCAP UK & Ireland continue to recommend the following key steps in all imported dogs – Checking for ticks and subsequent identification and treating for ticks if a tick treatment is not in place Treating dogs with praziquantel within 30 days of return to the UK in addition to the compulsory treatment Recognising clinical signs relevant to diseases in the countries visited or country of origin Screening for Leishmania spp., heartworm and exotic tick-borne disease in imported dogs

Answer 241

1. Consider seasonal risk and farm history of disease – utilising parasite forecasts 2. Animal management.- ounger animals are, in general, more susceptible to parasitic diseases, particularly calves and lambs entering their first and potentially second grazing season and should be kept on safer pastures. Grouping animals in tight age groups has benefits re. treatment and the usefulness of FEC in determining treatment requirements. Grouping animals also helps with other management actions such as weaning and withdrawal periods post treatment. Animals that have experienced repeated parasite infections should be kept on safer pastures and may be culled or not bred in favour of less susceptible animals. Overstocking should be avoided - heavily stocked pastures create a higher infestation risk than lightly stocked pastures. 3. Pasture and grazing management. - Nutritional stress - it is well documented that animals under nutritional stress are less able to withstand a challenge from internal parasites. Condition Scoring - using condition scoring to determine the need to treat animals can be a useful part of a parasite control strategy. Undegradable Protein - ewes fed a ration that has high levels of undegradable protein will produce fewer worm eggs in their faeces around lambing. Creep feeding lambs - provides additional nutritive support helping to delay early exposure to larvae on pasture. Grazing on bioactive forages (contain metabolites that have beneficial effects on health) - such as chicory, birdsfoot trefoil and sainfoin has been shown to reduce the negative effects of parasitism in sheep. 4. Use of parasiticides. Anthelmintics are drugs that treat helminths (parasitic worms) including roundworm, tapeworm, lungworm and liver fluke. Anthelmintics can be very effective and can target particular parasites or groups of parasites. However, anthelmintics need to be used appropriately 5. Diagnostic and performance testing. 6. Biosecurity, quarantine and biocontainment. Multi-species (mixed) grazing - not all species share the same parasites so grazing different species on the same pasture, either at the same time or in succession, can help to break parasite life-cycles

Answer 242

# Choose the right product – knowing the parasite that is present and targeting treatment produces better results and reduces the likelihood of retreatment. Source a narrow spectrum product where appropriate - reduces selection for resistance. Administer anthelmintics effectively and handle and store them correctly. Do not mix anthelmintics with any other product prior to administration. Check the product has been effective by carrying out post-dosing FEC.

Answer 243

farm animals - vary from drug to drug on their range of effect, e.g. albendazole is effective against roundworms, adult liver fluke and liver fluke eggs, whereas triclabendazole is effective against early immature liver fluke and adult liver fluke.

Answer 244

farm animals gastrointestinal and pulmonary nematodes, but has no activity against flukes and tapeworms and is not ovicidal.

Answer 245

farm animals | including avermectins and milbemycins - active against many immature nematodes and arthropods.

Answer 246

farm animals | monepantel is effective against nematodes resistant to other anthelmintics.

Answer 247

farm animals | Derquantel used against roundworms in sheep.

Answer 248

Diagnostic tests - such as Faecal Egg Counts (FEC) provide useful information when deciding the need for treatment, testing efficacy of a treatment and pasture management options. Performance testing – for example, looking at daily liveweight gain, can also help provide a more targeted approach to worm control by identifying the worst affected animals. Diagnostics and performance tests can identify issues before they become severe, can reduce the risk of anthelmintic resistance and improve dosing regimes.

Answer 249

Cattle - only a relatively small number of products are authorised for use against mites in cattle. Permethrin is the only pyrethroid in the UK used against chorioptic and sarcoptic mites in cattle. Chorioptic mange - ivermectin, doramectin, eprinomectin and moxidectin applied topically as a pour-on are effective against chorioptic mange. Sarcoptic mange – treatment with systemic macrocyclic lactones. Psoroptic mange – extremely rare in cattle in the UK and difficult to treat – studies have shown doramectin (two treatments) and permethrin (off license) to be effective. Sheep - as a result of resistance being demonstrated in Psoroptes ovis to the injectable macrocyclic lactones (ML) and concern that the use of these products is accelerating resistance to the MLs in gut-worm populations, there has been a recent move to more OP (diazinon) dipping for the treatment of sheep scab.

Answer 250

Cattle – topical application of pyrethroid starting before, and re-application throughout the challenge period is the standard preventative treatment. As ticks spend most of their life-cycle in the environment, reduction in numbers can be achieved through pasture improvement, drainage and scrub clearance. Sheep – cypermetherin and alphacypermethrin can be effective to treat and prevent ticks in sheep. Work continues at the Moredun Research Institute (MRI) to produce a new vaccine against the tick-borne disease louping Ill.

Answer 251

Cattle - insecticide impregnated ear tags and tail bands containing pyrethroids, together with pyrethroid pour-on, spot-on and sprays, are widely used to reduce fly annoyance in cattle. Sheep – blowfly populations are greatest during the summer months, although due to changes in climate the risk period can be from March to December in some areas. Control methods in sheep include – Shearing ewes prior to the onset of the high-risk period. Control of parasitic gastroenteritis and removal of contaminated fleece around tail area. Dipping or use of topical chemical formulations to prevent strike or inhibit larval growth. Ensure all wounds and foot lesions are treated promptly. Treatment of individual affected sheep involves physical removal of maggots, cleaning and disinfection of wounds and supportive treatment such as antibiotics, fluids and NSAIDs.

Answer 252

companion animals tapeworms

Answer 253

companion animals | roundworms, Taenia spp. and Lungworm

Answer 254

companion animals | roundworm, hookworm

Answer 255

companion animals | roundworms, hookworms and heartworm

Answer 256

companion animals | hookworms, roundworms, whipworms, heartworms

Answer 257

companion animal fleas, lice, ticks

Answer 258

companion animal flea

Answer 259

compoanion animal fleas and ticks

Answer 260

companion animal fleas and tickcs

Answer 261

``` Unicellular Prokaryotic Variety of shapes Peptidoglycan cell wall Reproduce by binary fission Variety of sources of nutrition ```

Answer 262

Pili or fimbriae are protein structures that extend from the bacterial cell envelope for a distance up to 2 μm They function to attach the cells to surfaces. E. coli cells can have up to 300 of these organelles can extend and retract to pull cell acrooss surfaces

Answer 263

Corkscrew-shaped Protein fibres Used for cell movement Only observable with staining Composed of filament, hook and basal body Generates propeller-type rotation Important in classification of strains/serotypes

Answer 264

``` Sticky layer that covers cell wall Polysaccharides and proteins Capsule = bound to cell Thinner = slime layer Various roles in virulence as well as protection against desiccation Aids attachment to host Avoidance of immune cells Creation of biofilms ```

Answer 265

Cell membrane carries out ATP synthesis Generation of proton gradient outside cell membrane Proton motive force drives ATP synthesis

Answer 266

peptidoglycan (murein) is an essential and specific component of the bacterial cell wall found on the outside of the cytoplasmic membrane of almost all bacteria . preserve cell integrity by withstanding the turgor- inhibition of its biosynthesis (mutation, antibiotic) or its specific degradation (e.g. by lysozyme) during cell growth will result in cell lysis. Peptidoglycan also contributes to the maintenance of a defined cell shape and serves as a scaffold for anchoring other cell envelope components such as proteins and teichoic acids It is intimately involved in the processes of cell growth and cell division. has a backbone of NAM and NAG linked to other backbones by peptide cross-bridges and vertically by side peptides

Answer 267

comprised of multiple peptidoglycan layers combined with teichoic acid molecules

Answer 268

thin peptidoglycan layer. an outer membrane overlies the peptiglycan in the periplasm and the membrane contains porin protiens. the outer half of the outer membrane contains lipopolysaccharide lps

Answer 269

Largest and most metabolically diverse phylum; include 1/3rd of all characterised species of bacteria Contain most bacteria of medical, industrial & agricultural significance All Gram-negatives with wide diversity in: Energy-generating mechanisms – chemolithotrophs, chemo-organotrophs & phototrophs Relationship to oxygen – anaerobes, microaerophiles & facultative aerobes Cell shape – straight/curved rods, cocci, spirilla, filamentous, budding & appendaged forms

Answer 270

second largest class Contain most Proteobacteria that grow with very low levels of nutrients - oligotrophs 10 orders Agriculturally important bacteria capable of nitrogen fixation in symbiosis with plants Several human and animal pathogens; most are obligate intracellular parasites ricketsiales rhizobiales

Answer 271

alphaproteobacteria Obligate intracellular parasites Reside within phagosome of infected host cell Key genus: Rickettsia Invades vascular endothelium Requires host ATP and nutrients Responsible for high mortality rates in humans and animals R. rickettsia (Rocky Mountain spotted fever) Transmitted from arthropods (tick bites) anaplasma, phagocytophylum infects ruminets, horses, humans

Answer 272

alphaproteobacteria Genus Brucella Localised in intracellular compartments of phagocytic, reticuloendothelial and specialised epithelial cells Pathologic effects in reproductive tissues Some zoonotic Brucella spp. Vaccination programmes for B. abortus and B. melitensis Detection via serology or molecular-based tests ‘Test and slaughter’ approach to control b. abortus- cattle, ruminents, horses

Answer 273

Over 75 genera and 400 species Include pathogenic species as well as those important in agriculture and natural ecosystems Bordetella sp.

Answer 274

betaproteobacteria destruction of ciliated respiratory epithelium (rhinitis, sinusitis, tracheitis) leading to pneumonia Burkholderia sp. cause pyogranulomatous lesions bordetella. avium- turkey bordetella. brocheoseptica- pigs, dogs, rabbits, rats horses cats bordetella parapertussis- lambs

Answer 275

``` Largest subgroup of proteobacteria (1500 species) Contains many human and animal pathogens Enterobacterales Pasteurellales Pseudomonadales ```

Answer 276

Cell growth phase Cell mass and size increase. Special enzymes break wall to allow expansion. DNA replication phase Chromosome is copied in preparation for division. Cytoskeleton aids separation of chromosomes No requirement for microtubular spindle apparatus or complex patterns of arrangement Binary fission phase Asexual reproduction Septum divides enlarged cell into two identical daughter cells. Replicating chromosomes attach to cell membrane in separate locations Cell continues to elongate pulling two identical chromosomes further apart Invagination of cell wall and membrane as new material is laid down Pulled together by fission ring Completion of new cell membrane and cell wall Septum material can dissolve slowly Daughter cells may not separate straight away Forms characteristic pairs, chains or clusters Each daughter cell then enters cell cycle

Answer 277

An oligotroph is an organism that thrives in an environment that offers very low levels of nutrients. Most bacteria are oligotrophs Spend majority of life in nutrient-limited state Infrequent division

Answer 278

- Adapting to new environment - Cell growth processes - Preparation for binary fission - Length will depend on metabolic activity of the population

Answer 279

- Exponential growth - Requires optimal metabolic and physiological conditions - Rapid increase in number of cells

Answer 280

Population growth is arrested | Limited by nutrient availability

Answer 281

Limited nutrients in closed system Cells start to die off Balanced state of cell death

Answer 282

Quorum sensing (QS) is a communication mechanism between bacteria that allows specific processes to be controlled, such as biofilm formation, virulence factor expression, production of secondary metabolites and stress adaptation mechanisms such as bacterial competition systems including secretion systems (SS)

Answer 283

Bacterial populations produce persisters, which are phenotypic variants of the wild type whose function is survival. Persisters are dormant, non-dividing cells that exhibit multidrug tolerance and survive treatment by all known antimicrobials.

Answer 284

Produced in response to nutrient limitation (starvation) Complex program of gene expression Single endospore created by mother cell Represents growth-arrested stage An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Firmicutes. ... In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. Thick peptidoglycan layer protects spore from outside environment Survives desiccation, extreme temperatures, chemical treatments and radiation Germination of endospores of B. antracis (anthrax), Clostridium sp. (botulism; tetanus) upon introduction to the body

Answer 285

``` Temperature pH Osmotic pressure Carbon Oxygen ```

Answer 286

Optimal growth temperature Supports best growth Shortest generation time ``` Five groups of organisms: Psychrophiles: range 0°C to 20°C Psychrotrophs: range 4°C to 39°C Mesophiles: range 10°C to 45°C Thermophiles: range 40°C to 70°C Hyperthermophiles: range 80°C to 115°C ```

Answer 287

``` Acidophiles: Grow best at pH below 5 Valuable in food/dairy industries Neutrophiles: Majority of species, including most bacterial pathogens Narrow range toleration Alkaliphiles: Grow best at pH above 8 ```

Answer 288

``` Extreme halophiles Require 20–30% salt Halophiles Some grow in 2–5% salt Others grow in 5–20% salt Halotolerant Can grow in ≤8% salt Non-halophiles Grow optimally <2% salt ```

Answer 289

Single circular chromosome Circular molecule of DNA with associated proteins Attached at one or several points to the plasma membrane Looped and folded DNA of E. coli is 1mm long which is 1,000 times longer than the entire cell Only takes up 10% of cell’s volume DNA is supercoiled

Answer 290

Many bacteria contain plasmids Plasmids contain their own origin of replication but rely on chromosomally encoded enzymes for replication Most are expendable – essential genes for growth encoded on chromosomes Stable, nonessential double-stranded DNA outside the nucleoid Host range – how many different types of bacterial cells they can exist/function in (1-1000) Number and type of genes encoded (5-100) Some organisms contain several different types of plasmid e.g. Borrelia burgdorferi contains 21 different linear/circular plasmids

Answer 291

Genes for proteins and pili

Answer 292

Genes for antibiotic resistance or poison resistance | May encode several antibiotic resistance genes

Answer 293

Genes for bacteriocins

Answer 294

Genes for toxins and other factors

Answer 295

during reproduction (cell division) between generations (i.e. parent to offspring)

Answer 296

between cells of the same generation: - Conjugation - Transformation - Transduction

Answer 297

Mechanism of genetic transfer that requires cell-to-cell contact Plasmid-encoded mechanism that can mediate DNA transfer between unrelated cells or even different genera Donor cell: contains conjugative plasmid Recipient cell: does not contain plasm

Answer 298

Genetic transfer process by which free DNA is incorporated into a recipient cell and brings about genetic change Several prokaryotes are naturally transformable - a cell that can take up DNA and be transformed is said to be competent Competence is genetically determined and regulated – competence specific proteins include: a membrane-associated DNA binding protein; a cell wall autolysin; and various nucleases Acinetobacter, Bacillus, Streptococcus, Haemophilus, Neisseria and Thermus – naturally competent/easy to transform Escherichia coli / other gram-negatives are not

Answer 299

a cell that can take up DNA and be transformed is said to be competent Competence is genetically determined and regulated – competence specific proteins include: a membrane-associated DNA binding protein; a cell wall autolysin; and various nucleases Acinetobacter, Bacillus, Streptococcus, Haemophilus, Neisseria and Thermus – naturally competent/easy to transform Escherichia coli / other gram-negatives are not

Answer 300

Transfer of DNA from one cell to another by a bacteriophage. Occurs naturally in many genera of bacteria e.g. Escherichia, Pseudomonas, Salmonella, Staphylococcus Not all bacteria are transducible and not all phages can transduce but phages outnumber prokaryotes by 10-fold Examples of genes transferred via transduction include many antibiotic resistance genes in Salmonella enterica serovar Typhimurium, Shiga-like toxin genes in E. coli and virulence factors in Vibrio cholerae

Answer 301

A mutation is a permanent and heritable change or disruption in the base sequence of the genome i.e. a change that is passed from the mother cell to daughter cells. Can be: Spontaneous: occur in the natural environment without the addition of mutagens (agents that cause mutations) – occur at a low rate, but the high rate at which many prokaryotes divide means that they can accumulate very rapidly Induced: created by the addition of mutagens Spontaneous mutations = random natural changes to DNA Errors made and not repaired One event per 106 or 1010 cycles of binary fission Induced mutations = changes produced by external physical or chemical agents called mutagens Physical example: radiation Chemical example: nitrous acid

Answer 302

One base in the DNA sequence changed to another base Transcript affected too Silent mutation = amino acid sequence not affected Due to redundancy of code Missense mutation = mutated codon calls for incorrect amino acid. Nonsense mutation = mutated codon is now a stop codon.

Answer 303

Inappropriate number of bases in a DNA sequence following mutation Affects entire reading frame of 3-letter codons after the point of change Frameshift mutation Potential catastrophic change in functionality of protein

Answer 304

Discrete segments of DNA that move as units from one location to another within other DNA moleculesTwo major types of transposable element in bacteria: Insertion sequences (IS) Transposons Always found inserted into another DNA molecule (plasmid, chromosome or viral genome) and do not possess their own origin of replication – only replicate when host DNA replicates Transposable elements can interrupt the sequence of essential genes when they move. Can be prime force behind spontaneous mutations Can move from: Chromosome to chromosome Chromosome to plasmid Plasmid to chromosome Plasmid to plasmid Between unrelated species Spread antibiotic resistance

Answer 305

Allows visual confirmation of mutations for antibiotic resistance When strains cultured on media containing antibiotics: Only resistant strains can grow; sensitive (wild-type) strains will die.

Answer 306

Culture media contain nutrients that promote cellular growth and reproduction: Liquid media = broths Tubes or flasks . Solidifying agent agar used for deeps, slants, and plates Agar is derived from red algae Non-nutritive so not consumed Used to examine colony characteristics Microbes vary in nutritional requirements. No single medium supports the growth of all microbes. Chemically defined medium Known chemical composition and amounts of all ingredients Complex medium Chemically undefined Contains plant or animal digests or yeast extracts Widely used in labs

Answer 307

components: Growth inhibitors Uses: Certain species are inhibited, while others are able to grow Examples:Mannitol salt agar for Staphylococcus

Answer 308

components:Dyes or indicator systems Uses:Visual difference between microbes is readily observable Examples: MacConkey agar for gram-negative bacteria

Answer 309

components:Special nutrients Uses:Fastidious microbes supported by addition of specific growth factors Examples: Blood agar for streptococci; chocolate agar for Neisseria

Answer 310

Xylose Lysine Deoxycholate (XLD) Agar is a selective medium for the isolation of Salmonella and Shigella spp from clinical specimens and food samples. XLD Agar was originally formulated by Taylor for the isolation and identification of Shigella from stool specimens. XLD Agar is both a selective and differential medium.

Answer 311

EMB is a selective, differential agar medium used for isolation of gram negative rods in a variety of specimen types. It is used frequently in clinical laboratories.

Answer 312

Pathogenicity is the ability to produce disease in a host organism Microbes express their pathogenicity by means of their virulence, a term which refers to the degree of pathogenicity of the microbe Pathogenicity can be defined as the capacity of a microbe to cause damage in a host Bacterial pathogens express a wide range of molecules that bind host cell targets to facilitate a variety of different host responses A key to fighting bacterial disease is the identification and characterisation of all these different strategies

Answer 313

``` Capsule Cell wall Toxins Adhesins Invasion Intracellular living Regulation and response ```

Answer 314

Presence of capsule interferes with receptor mediated phagocytosis and distinguishes those that posses them as pathogenic strains “Frustrated” phagocytosis Those with a capsule can ‘escape’ this line of defence Inhibits antibody binding Direct inhibition of phagocytosis Prevents capture by Neutrophil Extracellular Traps Bacterial cell wall components bind to receptors on macrophages Triggers release of cytokines Activates coagulation pathway, complement pathway and additional proinflammatory signals Excessive activation leads to damage to capillary endothelial cells Reduced perfusion Fever, hypotension, tissues destruction, acute respiratory distress, intravascular coagulation = multiple system organ failure (death)

Answer 315

exotoxins (produced inside gram positive bacteria) and endotoxins (produced as potion of cell wall in gram negative bacteria) Proteins produced by pathogenic bacteria which are secreted into the surrounding medium or directly injected into host cells These include: A-B toxins Proteolytic toxins Pore forming toxins

Answer 316

Subunit A: enzymatic activity Subunit B: binding and delivery Enzyme activity varies but can include proteolysis (e.g. tetanus or botulinum)

Answer 317

possibly AB toxin Proteolysis results in inability of vesicles to fuse with nerve cell membrane and release neurotransmitter Synpatobrevins are vesicle-associated membrane proteins

Answer 318

Membrane-disrupting toxins Pore-forming toxins are produce by many pathogenic Gram negative pathogens Act as virulence factors Six distinct families of PFTs Specificity determined by interactions with host cell Structural modularity bind to membrane and insert to form pore

Answer 319

Adhesion of pathogen to host surface Includes: Skin Mucous membranes Deeper tissues (lymphoid tissue; gastric and intestinal epithelia; alveolar lining; endothelial tissue Needs to avoid mechanical ‘clearing’ forces Adherence factors can be proteins or polysaccharides Proteins: Fimbrial (pili) Afimbrial Adherence factors can be proteins or polysaccharides Polysaccharides: Components of cell membrane, cell wall or capsule (e.g. teichoic acids; glucan, mannan)

Answer 320

Microbes produce enzymes that break down host tissues Aids tissue invasion Access to tissue niches for proliferation and dissemination Microbe remains outside cells

Answer 321

Microbes penetrates cells of host Survives within cells Variety of cell targets Some have obligate intracellular lifestyle (e.g. Chlamydia) A means of survival & proliferation Microbe actually penetrates cell of host tissue Survives inside cell environment Gram +ve, -ve and mycobacterial pathogenic species Phagocytic and non-phagocytic cell types Most bacteria use a type III secretion system to inject a chemical signal into their host cell Activates host cell signalling pathway Causes rearrangement of cell cytoskeleton so that bacteria is engulfed.

Answer 322

Reactive oxygen intermediates Lowering of pH of bacteria-containing vacuoles Activation of degradative proteases Inside an active phagolysosomal vacuole Inside a vacuole that hasn’t fused with a lysosome In host cell cytosol Three strategies for exit from host cell: Induced programmed cell (apoptosis) Host cell destruction Membrane-dependent exit

Answer 323

``` Biofilms can be defined as a microbially derived sessile community characterised by cells that are irreversibly attached to a surface or interface or to each other; are embedded in a matrix of extracellular polymeric substances that they have produced; and exhibit an altered phenotype with respect to growth rate and gene transcription Reduced penetration of antibiotic Neutralisation by certain bacterial enzymes Metabolic heterogeneity Oxygenation or pH gradients Persister cells Colony phenotype Antibiotic antagonism ```

Answer 324

A chemical substance produced by a micro-organism that inhibits bacteria e.g. penicillin

Answer 325

kills bacteria

Answer 326

prevents replication

Answer 327

length of time above MIC it needs

Answer 328

peak concentration it needs

Answer 329

1. Inhibition of bacterial cell wall synthesis 2. Inhibition of bacterial protein synthesis 3. Injury to the bacterial cell membrane 4. Inhibition of either DNA or RNA synthesis in the bacterium

Answer 330

Decreased uptake Efflux Enzymatic modification Enzymatic degradation Altered penicillin binding proteins (PBPs) Altered target Target overproduction

Answer 331

Reduced outer membrane (OM) permeability results in reduced uptake of antibiotics

Answer 332

Glycopeptides ``` β -lactams: Penicillins Cephalosporins Carbapenems Monobactams ``` β -lactamase inhibitors? Transpeptidase enzyme cross-links peptidoglycan chains to strengthen cell wall

Answer 333

folate antagonists are broad-spectrum agents that are effective against gram-positive and gram-negative organisms. Bacteria cannot absorb folic acid, but must make it from PABA (para-aminobenzoic acid), pteridine, and glutamate Sulphonamides Trimethoprim

Answer 334

Fluoroquinolones Nitroimidazoles Rifampin

Answer 335

Polymixins

Answer 336

``` Tetracyclines Aminoglycosides Chloramphenicol Macrolides Lincosamides Fusidic acid ```

Answer 337

cell wall inhibitor ``` Five classes- natural, aminopenacillins, pneacillinase- resistant penicillns, broad spectrum, beta-lactamsase inhibitors Time-dependent Hydrophilic Renal excretion Variety of administration routes Safe (but risk of hypersensitivity) Β-lactam ring ``` Destroyed by stomach acids - Development of penicillin-V which is resistant to stomach acid Destroyed by penicillinase: enzyme produced by many bacteria (mainly Staphylococci) that degrades penicillin.

Answer 338

``` Single or multi-component pumps Found in Gram +ve and Gram –ve Antibiotics (except polymyxins) susceptible to efflux systems Most are multi-drug transporters Increased gene expression = more pumps ``` creats resistance to: tetracycline aminoglycans b-lactams fluroquinolones

Answer 339

Aminoglycosides-modifying enzymes act as acetyltransferase, nucleotidyltransferase, or phosphotransferase enzymes Chloramphenicol acetyltransferase catalyses the acetylation of chloramphenicol and the resulting product does not bind to bacterial ribosomes creates resistance to: macrolides b-lactams aminogycosides

Answer 340

Interaction between antibiotic and target is very specific Mutations in penicillin binding proteins (PBPs) e.g. transpeptidase reduce affinity to β-lactam antibiotics Change in target site Spontaneous mutation or transposon-mediated Mutations in RNA polymerase (rifamycins) Mutations in DNA gyrase (quinolones) ``` creates resistance to: vancomycin MINOGLYCIDES FLUROQUINOLINES PENECILIN ```

Answer 341

``` Antimetabolite antibiotics can be counteracted by overproduction of the relevant enzyme or bypassing the metabolic pathway creates resistance to: vancomycin trimethoropin tetracycline sulfonamide ```

Answer 342

Granulomatous enteritis of ruminant animals Granulomas: form when immune system attempts to wall off foreign substances results in thickening of intestine, inhibits nutrient absorption Caused by Mycobacterium avium ssp. paratuberculosis Initial signs of MAP infection are subtle: Decreased milk production, reduced BCS, low fertility, roughening of the hair coat Clinical characteristics Loose manure Weight loss Chronic & Progressive No cure dehydration, cachexia, death Causative bacteria found on ~70% of U.S. dairy farms UK prevalence data are limited, but bacteria likely on >50% of UK dairy farms

Answer 343

E.g., Tuberculosis, Leprosy Slow-growing, resilient Resistant to acids, alkalis, and detergents Confirmed by acid-fast (Ziehl Neelsen) stain

Answer 344

When MAP reaches the ileum it is transported through the cells covering the Peyer’s patches and is taken up by macrophages in the stroma Leads to excessive expression of IL-10 and decreased expression of MHC molecules Instead of being destroyed by the macrophages, MAP proliferates within them When macrophages rupture, MAP is released into neighboring tissue and taken up by other macrophages Initially a Th1-type immune response predominates, then a Th2-type response  Th2 regulatory cytokines are involved in triggering the humoral immune response  During this shift, cows shed MAP in increasing amounts. Infection spreads to other tissues Leads to excessive expression of IL-10 and decreased expression of MHC molecules Instead of being destroyed by the macrophages, MAP proliferates within them When macrophages rupture, MAP is released into neighboring tissue and taken up by other macrophages Granulomas form when the immune system responds by recruiting additional monocytes and lymphocytes (types of white blood cells) These cells fuse together into multinucleated giant cells and epithelioid cells Results in visible thickening of intestinal mucosa, which inhibits nutrient absorption and leads to clinical symptoms of the disease

Answer 345

Main types: ELISA, PCR, Culture -- ELISA detects MAP antibodies, PCR and culture detect causal organism -- Diagnostic matrices for ante-mortem testing are serum, milk, or fecal samples Post-mortem diagnoses are typically obtained via bacterial culture of tissues from intestinal regions such as the ilium, ileocecal junction, ileocecal lymph nodes, or mesenteric lymph nodes Culture: costly, takes 16 weeks, lacks sensitivity (MAP is fastidious– requires mycobactin J, a siderophore for growth) ELISA: lacks sensitivity (no antibody production in early infection stages) PCR: some of the targets aren’t specific to MAP, found in other mycobacterial species, can be bad at differentiating between live and dead bacteria

Answer 346

Management of the calving area Hygiene of partiparturient animals (Ansari-Lari et al., 2009) Individual calving areas (not doubling as sick pens or shared with other lactating cows; Pithua et al., 2011) Colostrum/milk management Avoid raw pooled colostrum (Nielsen et al., 2008) or feed milk replacer (Muskens et al., 2003) Pasture management Spreading manure linked to higher infection risk (Obasanjo et al., 1997) Avoid sharing pasture between adults and heifers (Marce et al., 2011) Implement a test and cull program , source replacement animals from a single negative herd (Orpin et al., 2005)

Answer 347

need to consume other organisms to live

Answer 348

live off dead or decomposing organic matter

Answer 349

use organic chemicals and compounds as carbon source

Answer 350

Enzymes synthesised inside fungal hyphae Excreted via exocytosis Act on surrounding medium to break it down Digested organic compounds are then reabsorbed in solution through the cell wall Large surface area aids absorption

Answer 351

feed off living cells

Answer 352

invade living cells, kill them then digest

Answer 353

hyphal tip extension Cell wall softened at tip Turgor pressure extends wall Increase in length as opposed to width Increases surface area for absorption

Answer 354

Cell wall is composed of β-glucan and chitin to provide strength and rigidity and resist osmotic stress Cell membrane is similar to other eukaryotes but has ergosterol instead of cholesterol

Answer 355

multicellular fungi

Answer 356

unicellular fungi Unicellular, non-filamentous Facultative anaerobes: carry out aerobic respiration when O₂ is available and anaerobic (fermentation) when no O₂ available Reproduce by mitosis

Answer 357

display both yeastlike and moldlike growth

Answer 358

Made up of hyphae | Extensive tissue invasion

Answer 359

cross walls that form between cells but often have pores to allow movement of cytoplasm and organelles (oposite of coenocytic hyphae

Answer 360

oposite of septate hypahe The continuous tubes hyphae filled with multinucleated cytoplasm are called coenocytic hyphae. These are nonseptate or do not have cross walls in their hyphae.

Answer 361

conidia on conidiophores

Answer 362

produce sporangiospores on sporangiophores

Answer 363

Produced as a result of sexual reproduction Thicker cell walls protect from abiotic and biotic factors Harder to eradicat

Answer 364

Infection by a fungal agent is called mycosis Mycoses are generally chronic conditions because fungi grow slowly Classification is based on the type of tissue infected and the mode of entry into the body - Systemic (lungs, deep tissue/organs) - Subcutaneous (beneath the skin) - Cutaneous (skin, hair and nails) -Superficial (skin surface, hair shafts) - Opportunistic (immune suppression)

Answer 365

the genera microsporum and trichophyton Arthrospores/conidia are source of infection Entry via injured skin, scars and burns Colonisation of keratinised layers Invade and multiply within keratinised tissues Produce keratinase Induces inflammatory reactions Move away from infection site Need to overcome biotic and abiotic factors (primary defences) Adherence and penetration is slow (2-5 days) Carbohydrate-specific adhesins on surface of conidia Secreted proteases can facilitate adherence Fibrillar projections connect conidia to keratinocytes (skin surface Hyphae grow centrifugally from the initial lesion towards normal skin, producing typical ringworm lesions Alopecia, tissue repair and nonviable hyphae are found at the centres of lesions as they develop Growth of hyphae can result in epidermal hyperplasia (overgrowth of skin cells) and hyperkeratosis (thickening of outer layer of skin). Strategies: Adherence Invasion Colonisation and spread Immunosuppression

Answer 366

Microsporum canis; gallinae; gypseum; nanum Large, rough, thick-walled multiseptate macroconidia Fusiform to obovate Attack hair and skin Most commondermatophyte

Answer 367

mentagrophytes; equinum; verrucosum Rarely produce macroconidia Single-cell microconidia are numerous Solitary or in clusters Attack hair, skin, nails, horns, claws

Answer 368

Primarily a respiratory infection Spores are very small Can pass through upper respiratory tract Carried to terminal part of bronchial tree Spore germination and invasion of tissue is controlled by many factors No true virulence factors Combination of factors leads to disease state

Answer 369

assosiated with the hyphae induces cell apoptosis, eithelial cell damage inhibition of phagocitosis and t-cell response

Answer 370

assosiated with hyphae inhibitd neutrophil mediated hyphal damage ribosome inactivating toxin found in aspergillus

Answer 371

assosiated with hyphae and condia | affects transepithelial resistance

Answer 372

assosiated with the hyphae assosiated with the hyphae damages epithelial cells and slows ciliary beating. angiogenesis inhibitor

Answer 373

assosiated with the hyphae | damages epithelial cells and slows ciliary beating.

Answer 374

Hyphal invasion of blood vessels Vasculitis and thrombus formation Formation of mycotic granulomas in the lungs Vascular dissemination Colonisation and invasion of other internal organs Additional mycotic granulomas

Answer 375

Commensal yeast that lives on mucosal membranes Pleomorphic switch from yeast to filamentous growth Phagocytic clearance eliminates most yeast cells Those that survive convert to hyphal forms ``` Enables tissue penetration and resistance to phagocytosis Adherence Avoidance Flexibility Integrin-like molecules on cell surface ``` Allows adhesion to matrix proteins on mucosal cells Secretion of toxins; proteinases; lipases and phospholipases to aid tissue invasion Msb2p counteracts complement system (antimicrobials) Pre-disposing factors e.g. defective cell-mediated immunity, concurrent disease, prolonged use of antimicrobials, damage from catheters Vascular invasion by hyphae Haematogenous spread Production of systemic lesions

Answer 376

the consequence of ingestion of grains or forage containing toxic metabolites produced by certain fungi. Fungi that produce toxins often do so only under specific conditions of warmth, moisture and humidity.

Answer 377

Outbreaks are often seasonal and sporadic * May be associated with particular batches of stored feed or certain types of pasture * No evidence of transmission to in-contact animals * Susceptibility can vary with the species, age and sex of the animals exposed * Clinical presentation may be ill-defined * Antimicrobial treatment is ineffective * Recovery depends on type and amount of mycotoxin ingested and the duration of exposure to contaminated food * Characteristic lesions in target organs of affected animals provide supporting diagnostic evidence * Confirmation requires demonstration of significant levels of a specific mycotoxin in suspect feed or in tissues of affected animals

Answer 378

Aflatoxins are a group of approximately 20 related toxic compounds produced by some strains of Aspergillus flavus, Aspergillus parasiticus and a number of other Aspergillus species during growth on natural substrates including growing crops and stored food. These fungi are ubiquitous, saprophytic moulds which grow on a variety of cereal grains and foodstuffs such as maize, cottonseed and groundnuts. About half of the strains of A. flavus and A. parasiticus are toxigenic under optimal environmental conditions. High humidity and high temperatures during preharvesting, harvesting, transportation and storage, as well as damage to field crops by insects, drought and mechanical injury during harvesting favour the growth of A. flavus and toxin production. effects all animals

Answer 379

a group of related difuranocoumarin compounds with toxic, carcinogenic, teratogenic and mutagenic activity. The four major aflatoxins are B1, B2, G1 and G2. Aflatoxin B1 (AFB1) is the most commonly occurring and also the most toxic and carcinogenic member of the group Most of the other aflatoxins are metabolites formed endogenously in animals after ingestion or administration of aflatoxins. Aflatoxins are stable compounds in food and feed products and are relatively resistant to heat. may be degraded by sunlight. They have a low molecular weight and are nonantigenic in their native state. The toxic effects of aflatoxins are dose-, time- and species-dependent. Mature ruminants are less susceptible than young animals and monogastric animals. The toxins are absorbed from the stomach and metabolized in the liver to a range of toxic and nontoxic metabolites which are then excreted in urine and milk. The major biological effects of aflatoxins include: inhibition of RNA and protein synthesis, impairment of hepatic function, carcinogenesis immunosuppression. AFB1 is bioactivated in the liver to a highly reactive intermediate compound which reacts with various nucleophiles in the cell and binds covalently with DNA, RNA and protein. After deliberate administration of AFB1 there is marked interference with protein synthesis at the translational level which seems to correlate with disaggregation of polyribosomes in the endoplasmic reticulum. Many of the toxic responses observed in animals resulting from AFB1 activity can be attributed to alterations in carbohydrate and lipid metabolism and interference with mitochondrial respiration. Short-term effects include acute toxicity with clinical evidence of hepatic injury and nervous signs such as ataxia and convulsions. In acutely affected animals death may occur suddenly. Long-term consumption of low levels of aflatoxins probably constitutes a much more serious veterinary problem than acute, fulminating outbreaks of aflatoxicosis. With chronic aflatoxicosis there is reduction in efficiency of food conversion, depressed daily weight gain, decreased milk production in dairy cattle and enhanced susceptibility to intercurrent infections in most species due to immunosuppression. AFB1 is also an extremely potent hepatocarcinogen in many species of animals.

Answer 380

produced by several species of the genus Fusarium responsible for the leukoencephalomacia in equine species and rabbits pulmonary edema and hydrothorax in pigs

Answer 381

produced by fungi of the genera Fusarium, Myrothecium, Phomopsis, Stachybotrys, Trichoderma, Trichotecium, Verticimonosporium and possibly others strong capacity to inhibit eukaryotic protein synthesis, interfering in the initiation, the elongation and termination steps of protein synthesis DON is the mycotoxin most commonly found in grains. When ingested in high doses by animals it causes nausea, vomiting and diarrhea. When ingested by pigs and other animals in small doses it can cause weight loss and the refusal to eat. Due to these symptoms induced by deoxynivalenol it is known as vomitoxin or food refusal factor. Although less toxic than other trichothecenes, DON is more common in the seeds of safflower, barley, rye, and wheat and in feed mixtures

Answer 382

secondary metabolite produced mainly by Fusarium graminearum The association between the consumption of moldy grains and hyperestrogenism in pigs High concentrations of zearalenone in pig feed may cause disturbances related to conception, abortion and other problems

Answer 383

first isolated from secondary metabolites of Penicillium citrinum other species of Penicillium (Penicillium expansum and Penicillium viridicatum) and even of Aspergillus (Aspergillus niveus and Aspergillus terreus) also showed the capacity to produce these substances. onsidered responsible for nephropathy in pigs and other animals, although its acute toxicity varies depending on the animal species Oat (moldy), rye, barley, corn and wheat grains

Answer 384

cereal grains infected by Claviceps purpurea Also known as ergotism Ergotism has two classic forms: gangrenous and convulsive. The animals which are susceptible to intoxication include cattle, ovine species, pigs and birds. The clinical symptoms of ergotism in these animals manifest in the form of gangrene, abortion, convulsions, suppression of lactation, hypersensitivity and ataxia (loss of coordination of voluntary muscular movements)

Answer 385

Ochratoxin A has been found in oats, barley, wheat, coffee grains and other products for human and animal consumption metabolite of Aspergillus ochraceus associated with nephropathy in all animals studied to date also shows hepatoxic, immunosuppressive, teratogenic and carcinogenic behavior

Answer 386

``` Aflatoxins ergot alkaloids fumosins trichothecenes zearakenone citrinin ochratoxin A ```

Answer 387

C. neoformans and C. gatti are dimorphic basidiomycetous fungi Oval haploid budding yeast (vegetative growth) Transition to filamentous sexual stage (Filobasidiella neoformans) known as a teleomorph Important fungal infection of humans and animals Primarily infects immune-compromised patients Most common in cats Also seen in dogs, cattle, horses, sheep, goats, birds and wild animals Virulence factors: Polysaccharide capsule Melanin Mannitol Enzymes “Sugar coated killer” Phenotypic switching Development of pulmonary lesions Dissemination via hematogenous spread in macrophages Localisation in central nervous system Cross blood brain barrier (BBMB) via transcytosis or inside infected macrophages Formation of lesions in the brain Results in neurological signs Infection can spread to the eye along optic nerves or hematogenous dissemination Results in cryptococcal optic neuritis and retinitis Most common systemic mycosis Chronic infection causing listlessness and weight loss Cutaneous legions, some large and ulcerative Upper respiratory signs such as sneezing, chronic nasal discharge, polyp-like masses, subcutaneous swelling over the bridge of the nose Neurological symptoms include depression, changes in temperament, seizures, circling, paresis and blindness Optic signs include dilated, unresponsive pupils, blindness, inflammation of ocular structures Dogs present meningoencephalitis, optic neuritis and granulomatous chorioretinitis Disseminated disease with CNS or ocular involvement more common than respiratory Cytologic evaluation of: Nasal exudate Skin exudate Cerebrospinal fluid Paracentesis of aqueous or vitreous chambers of the eye Impression smears of nasal or cutaneous masses

Answer 388

Alterations in cell membrane and capsule structure Allows cells to persist in the host by minimising the inflammatory response

Answer 389

Seen in cats, dogs, horses, donkeys, pigs, fowl, goats and cattle Most common in cats and dogs Entry of spores (conidia) or mycelia through broken skin Subcutaneous/lymphocutaneous: most common form Pulmonary: rare but possible via breathing in fungal spores Disseminated: spread of infection to other parts of the body (immunocompromised patient Conversion from mycelial to yeast form upon entry Production of extracellular enzymes and adhesins allow adhesion to and invasion of cutaneous and subcutaneous tissue Adhesion to extracellular protein fibronectin Proteinases I and II hydrolyse stratum corneum cells Definitive diagnosis relies on culture of both forms Prognosis is good Long treatment duration requires owner compliance Itraconazole is feline drug of choice

Answer 390

target the cell membrane- AMPHOTERICIN ECHINOCANDINS AZOLES MACROLIDES target mitosis/ replication- GRISEOFULVIN target by DNA synthesis- FLUCYTOSINE

Answer 391

targets celll membrane creates artificial ion channel Amphotericin binds fungal membrane ergosterol (fungal cholesterol) causing: Increased membrane permeability and Creation of transmembrane channels (pores) Resulting in: Leakage of monovalent ions (K+, Na+, H+, and Cl-), Leakage of macromolecules from fungal cell ``` Other mechanisms: Stimulates fungus to produce oxygen radicles Modulation of macrophage activity Stimulates pro-inflammatory cytokines Reactive oxygen intermediates Nitric oxide Eventually cell death ``` can enhance other antifungals good for disseminated aspergillus “Conventional” Amphotericin B deoxycholate (AmB-d) Newer (lipid-based) formulations Liposomal amphotericin B (L-AmB) Amphotericin B lipid complex (ABLC) Amphotericin B colloidal dispersion (ABCD) Many others- Fewer side effects: lipid vehicle acts as reservoirs, reducing binding to cells Improved tolerability Altered tissue penetration – more in liver, spleen and brain, less in lung and kidneys Reduced toxicity (esp. nephrotoxicity and anaemia) However, compared to AmB-D these formulations are less potent by mg dose Resistance: Dermatophytes- no ergosterol Pythium Candida- resistence ``` Antifungal Spectra: Candida spp Rhodotorula spp Cryptococcus neoformans Histoplasma capsulatum Blastomyces dermatitidis Coccidioides immitis Trichophyton Microsporum Epidermophyton spp ```

Answer 392

``` enilconazole fluconazole itraconazole ketoconazole thiabendazole ``` change permiability of membrane by inhibiting synthesis of ergosterol Resistance: No major ``` Antifungal Spectra Blastomyces dermatitidis Paracoccidioides brasiliensis Histoplasma capsulatum Candida spp Coccidioides immitis Cryptococcus neoformans Aspergillus fumigatus used in mild to moderate disease or in combination in severe disease ``` ``` Inhibition of CYP450 results in reduction of: Progesterone Pregnenolone Corticosterone Aldosterone Cortisol Estrone Estradiol Estriol ```

Answer 393

``` enhances other anti fungals Mechanism Converted to fluorouracil Inhibits RNA synthesis Inhibits protein synthesis Resistance Can develop over course of treatment ``` ``` Antifungal Spectra Cryptococcus neoformans Candida albicans, Candida spp Torulopsis glabrata Sporothrix schenckii Aspergillus spp ``` Adverse Effects and Toxicity: Vomiting Diarrhoea Reversible hepatic and hematologic effects (increased liver enzymes, anaemia, neutropenia, thrombocytopenia). Interactions: Synergistic antifungal activity between amphotericin B and ketoconazole. Renal effects of amphotericin B prolong elimination of flucytosine.

Answer 394

Mitotic Inhibitor Inhibits formation of the mitotic spindle. ``` Fungistatic Prevents fungi growth rather than killing the fungi. Use Dermatophyte infections Resistance Can develop over course of treatment Antifungal Spectra Microsporum Epidermophyton Trichophyton spp. Actinomyces Nocardia spp Adverse Effects and Toxicity: Rare Vomiting Diarrhoea Teratogenic (contraindicated in pregnant animals especially mares and queens) ``` Interactions Lipids increase GI absorption of griseofulvin.

Answer 395

is the infectious particle composed of nucleic acid, protein capsid, +/- envelope may be extracellular or intracellular Has viral surface proteins that attach to host cell surface proteins which allow entry into a cell.

Answer 396

Four aspects of virus replication Entry – binding to host cells and entering the cell Replication – Producing new copies of the genome Assesmbly – producing new virus particles Release – Exiting the cell to infect a new host or a new cell within the current host

Answer 397

Virus has to bind to cells Binding can occur via cellular proteins that act as receptors IMPORTANT to realize that receptors are normal cell proteins that viruses hijack they are not there just for the viruses – they have normal cellular functions Receptors tend to be virus-specific Multiple viruses can bind the same receptors Some receptors bind viruses but don’t facilitate infection – pseudo receptors Can also be cell type specific – if virus has specific host cell tropism Not all cell-surface molecules are able to bind virus, if the virus binds to a different molecule no entry is possible RSFV binds to lrp1 Found on all cell types a ubiquitous receptor allows the virus to enter lots of different cell types Rabies virus binds to Acetylcholine receptor Found on muscle cells and the synapses between the nerve and muscle cells – allows the virus to infect muscle and neurons Poxviruses thought to bind to glycosaminoglycans These are universal throughout the cells, but it is likely that the virus has specific tropisms to different cells, which is a result of downstream signalling within the cell, not binding

Answer 398

Viruses hijack the cells systems to replicate – they cannot do it without the cellular machinery Can occur in the cytoplasm or the nucleus – on membranes on in complexes Viral proteins also interact with the cellular systems to inhibit cellular transcription or activate other cellular pathways to facilitate infection Replication occurs in the nucleus for all but one group of DNA viruses One exception to the rule is Pox viruses (monkeypox) that replicate in Cytoplasm mRNA’s are then moved out to the cytoplasm for translation and assembly Viruses uncoat once they enter the cell – Genomic material released for replication Genomic material is either immediately transcribed (DNA/RNA viruses) or requires an extra step ( negative sense viruses, and retroviruses) Viruses hijack the host cell systems and produce proteins using the host cell resources, though RNA viruses use their own replication complex proteins

Answer 399

complexes in the cytoplasm No use of the DNA so must carry their own polymerase Activation of various genes in early, intermediate and late phase to facilitate replication and assembly

Answer 400

Virus enters the cell Uncoats and the genomic RNA starts producing protein RNA then generates a replicative intermediate to generate a new genomic RNA Packaged and then exits the cell

Answer 401

Virus enters cell and uncoats mRNA is produced to produce protein Replication occurs by way of a dsRNA intermediate Virus assembly from proteins and the genomic RNA Cell exit

Answer 402

Virus enters the cell The RNA is reverse transcribed and then imported into the nucleus Integrated and then transcribed to produce mRNA Translated into proteins and then assembly of the virus and release from the cell

Answer 403

Surface proteins, either envelope proteins and/or capsids packaged to produce new viruses

Answer 404

2 main ways: Budding from cell using host lipids and generating new enveloped viruses Lysis of the cell releasing virus into the environment

Answer 405

parainfluenza virus, canine adenovirus and Bordetella bronchiseptica, as well as mycoplasmas, Streptococcus equi subsp. zooepidemicus, canine herpesvirus and reovirus-1,-2 and -3.

Answer 406

Type of virus: 50- to 200-nm virion consisting of a nucleocapsid surrounded by a lipid envelope that is obtained as the nucelocapsid buds from the plasma membrane of an infected cell. All PIVs, including CPIV, have a single-stranded, nonsegmented, negative-sense RNA genome Pathogenesis and relevant virulence factors: Incubation period: 3 to 10 days after infection, and viral shedding typically occurs 6 to 8 days after infection Clinical signs and potential outcome: Persistent cough Fever Nasal discharge Sneezing Eye inflammation Lethargy Loss of appetite CPIV suppresses the innate branch of the immune system and causes the loss of cilia and ciliated epithelium, it makes conditions more favorable for coinfections. In puppies or immunosuppressed adult dogs, the presence of CPIV in coinfections can lead to a more severe pneumonia and can be fatal. Diagnosis: based on the dog's medical history, clinical signs, vaccination history and physical exam. If a specific diagnosis of canine parainfluenza is needed, ocular and oral swabs can be submitted to the lab for PCR testing to confirm the presence of CPIV. non-core Administer at 6–8 weeks of age, then every 2–4 weeks until 16 weeks of age or older [EB4

Answer 407

Infection is easily transmitted between infected rabbits by the oral, nasal or conjunctival routes, with the digestive system and respiratory tract as the main portals. Only a few virions are required to produce infection. Food bowls and bedding can transmit infection. Carcases from wild rabbits that died from RHD can be a source of infection, by spreading the virus via the faeces of scavengers. RHD has a short incubation period of one to four days. The virus replicates in many tissues, including the lung, liver and spleen, with subsequent viraemia and haemorrhage. Viral tropism is for hepatocytes. The disease it causes is essentially a necrotising hepatitis, often associated with necrosis of the spleen. Disseminated intravascular coagulation produces fibrinous thrombi in small blood vessels in most organs, notably the lungs, heart and kidneys, resulting in haemorrhages. Death is due to disseminated intravascular coagulopathy or liver failure. Peracute, with animals found dead within hours of eating and behaving normally. This is a common presentation Acute, with affected rabbits showing lethargy, pyrexia (above 40°C) and increased respiratory rate. These animals usually die within 12 hours. Subacute, with rabbits showing mild or subclinical signs from which they recover and become immune to infection.

Answer 408

Two forms of the disease Mild enteric disease in kittens – GI tract Feline Infectious Peritonitis – can be fatal Mutations in the virus lead to the difference in the virus resulting in FIPV – lethal version of the disease Mortality is high once symptoms occur FECVs show a pronounced tropism toward epithelial cells in the gut, but they are also able to infect monocytes, albeit inefficiently. It was suggested that in monocytes—rather than in intestinal epithelial cells

Answer 409

FIP develops in approximately 5% of cats that are persistently infected with FECV FECVs acquire mutations that can convert them into FIPVs (Pedersen et al., 2012). The resulting FIPVs display an altered cell tropism; they infect and replicate efficiently in monocytes and macrophages. This property is considered a key step in the development of FIP. One gene the 3c shows a full-length gene in FECV Essential for replication in the gut – pathogenesis of FECV In FIPV this 3c gene shows mutations and a truncated gene Hypothesise that this might result in increased tropisms for macrophages – FIPV Spike protein can also show 2 mutations in the protein consistent in FIPV sequences – results in increased disease outcome

Answer 410

Bluetongue is characterised by changes to the mucous membranes of the mouth and nose, and the coronary band of the foot. Clinical signs are generally more severe in sheep but cattle can show signs of disease. A veterinary surgeon must be contacted by the farmer where large numbers of sheep or cattle present with lameness, high rectal temperatures, salivation, lacrimation and ocular and nasal discharges. Bluetongue is a notifiable disease in the UK Midges – culicoides spp. are the vector Ruminants can be infected, primarily sheep Once the sheep is infected – enters the lymph nodes and then needs to get into the blood to continue transmission Symptoms are a result of the prolonged viremia Midge bite in the skin results in recruitment of APC’s at the bite site and virus migration to the lymphoid cells BTV replicates within mononuclear phagocytic and endothelial cells, lymphocytes and possibly other cell types in lymphoid tissues, the lungs, skin and other tissues. Followed by migration to the blood – circulates around the body Infected ruminants may exhibit a prolonged but not persistent viraemia and BTV is associated with erythrocytes during the late stages of this prolonged viraemia. The prolonged viremia results in injury to small blood vessels in target tissues – show the characteristic blue tongue Shows haemorrhage and ulcers in the oral cavity and upper gastrointestinal tract; necrosis of skeletal and cardiac muscle; coronitis; subintimal haemorrhage in the pulmonary artery; oedema of the lungs, ventral subcutis, and fascia of the muscles of the neck and abdominal wall; and pericardial, pleural and abdominal effusions.

Answer 411

Clinical signs of canine herpesvirus if presented are: Lethargy Decreased suckling Diarrhea Nasal discharge Conjunctivitis Corneal edema Red rash, rarely oral or genital vesicles Soft, yellow-green feces Notable absence of fever CHV is primarily lethal in neonates (1-4 weeks old) If infected after 1-2 weeks they will generally survive Timing is therefore key to survival Infection is by oronasal secretions of other dogs/mother or otherwise Incubation period is 6-10 days Duration of illness is 1-3 days Herpesviruses only infect neonates due to the immature immune system Not just in dogs, but also in humans very similar disseminated herpes infection— the most dangerous type of herpes infection. The herpes virus is spread throughout the neonates body and can affect multiple organs, including the liver, brain, lungs, and kidney. Why do adults not get it? Functional immune system Can result in latency Latency is a hallmark of herpesvirus infections The viral genome exists as an episome (naked, circular DNA) in the host cell nucleus No virus is produced until reactivation Not the same as persistent infection (continuous viral production) E.g. VZV, which causes chickenpox in children, causes shingles when reactivated in the adult

Answer 412

The flu virus is an RNA virus The genome codes for five viral proteins and is made of eight fragments. The virus has a lipid envelope with two glycoproteins present Haemagglutinin - this glycoprotein plays a part in infection and provides the “H” in the strain type. Haemagglutinin attaches the virus to cells and allows the viral envelope to fuse with the cell membrane and enter cells. Neuraminidase –its role is to allow the release of viruses to infect other cells Different combinations of H and N glycoproteins give rise to different strains Mutations which produce small changes in antigens are referred to as antigenic drift and these occur in the same strain Mutations which result in a major change and produce new strains are referred to as antigenic shifts The virus is spread by inhalation or by direct contact. Reservoirs of infection are primarily humans, but birds and pigs can act as reservoirs. The multiple host status makes for mixing of flu types Avian Influenza only transmits to humans in close contact Evidence of HPAI Avian Influenza – reportable disease

Answer 413

Double stranded DNA virus Only DNA virus known to be transmitted by arthropods. Causes haemorrhagic fever- high mortality rate in domestic pigs Has an enzootic cycle in addition Warthogs and bushpigs with soft ticks as the vectors Eradicated outside of Africa in 1990’s with exception of epidemic in Portugal in 1999 Endemic in Africa Re-emerging in Europe Zoonotic disease Ticks bite wild animals – get infected with ASFV Once infected, they are infected for life – can transmit even as they moult from larvae – nymph – adult tick Bite domesticated animals – pigs get infected and can then transmit pig-pig. No horizontal transmission in wild animals If pigs are free-range – increased likelihood of contact with ticks Like other DNA viruses had early, intermediate and late gene expression Replicates in both nucleus and cytoplasm Changes in the host result in increased pathogenesis

Answer 414

``` higher cost adjuvent needed good stability no reversion provided no mucosal immunity, antibody memory response the immunity is short lived ```

Answer 415

``` lower cost adjuvent not needed poor stability reversion is possible provides mucosal immunity, antibody an dCTL immunity long term immunity ```

Answer 416

Viruses use our own cells to replicate so anything that targets them also targets our cells Can have some issues with toxicity – even long-term HIV drug use can affect the body – have some long-term events Nucleoside analogues are commonly used in veterinary medicine

Answer 417

Most chromosomes in Dogs are acrocentric | Centromere are very off center ( reminisant of Y)

Answer 418

Centromere is in the center of chromososme (reminisant of x)

Answer 419

Centromere is just a bit off center in Chromosome

Answer 420

the condition of having an abnormal number of chromosomes in a haploid set

Answer 421

nucleotide

Answer 422

Sugar Phosphate Nitrogenous base

Answer 423

All organisms must replicate their DNA accurately before each cell division Replication is connected to the cell cycle g0- cell cycle arrest g1- cellular contents, excluding chromosomes, are duplicated s- each of the 46 chromosomes is duplicated by the cell g2- cell cycle double checks the duplicated chromosomes for error and nned of repairs mitosis cytokenesis repeat Each parental strand acts as a template New strand synthesised against template Each resultant daughter molecule has one old and one new strand

Answer 424

DNA is packaged into chromosomes Compacted to fit inside cells Protects DNA from damage Creates organisation and structure of DNA Efficient transmission to both daughter cells during division chromosome is made up of centromere and telomere Visible during mitosis when chromatin is condensed Seventy-eight (39 pairs) in somatic cells of dogs Thirty-eight (19 pairs) in somatic cells of cats Sixty (30 pairs) in somatic cells of cows Each pair has the same banding pattern and centromere position

Answer 425

an exact multiple of the haploid (n) chromosome number e.g. Triploidy (3N) and tetraploidy(4N)

Answer 426

Any other abnomal number of chromosomes thats not an exact multiple eg downs syndrome in humans

Answer 427

Monosomy for an entire chromosome is almost always lethal; an important exception is monosomy for the X chromosome, as seen in Turner syndrome- only one X chromosome Known as a mosaque karyotype Effects fertility as gametes with no genetic info are produced

Answer 428

A break in a chromosome results in deleted genetic material

Answer 429

A duplication on genetic material

Answer 430

A break in the chromosome causes reinserted and reordered genetic material

Answer 431

Genetic material from one chromosome attaches to another

Answer 432

Most common form of translocation Breakage and rejoining in acrocentric chromosomes results in a long chromosome and a fragmet which is lost, reducing the number of chromosomes. Does not always result in health conditions

Answer 433

G1 Checkpoint: Rest or divide? S Checkpoint: DNA OK? G2 Checkpoint: Fully equipped? M Checkpoint: Is everyone lined up?

Answer 434

``` Build up of substrate will interfere with cellular function Clinical signs include: • failure to thrive • incoordination and balance issues • exercise intolerance • abnormal vision • fainting • seizures ```

Answer 435

Interphase- The cell spends most of its life in this phase. The DNA in chromosomes copies itself ready for mitosis. Prophase- The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears. Metaphase- Chromosomes and their copies line up in the middle of the cell. Anaphase- Chromosomes and their copies are pulled to different ends of the cell. Telophase- New membranes form around the chromosomes at each end of the cell. Cytokinesis- The cell membrane pinches in and eventually divides into two daughter cells.

Answer 436

Four haploid cells are formed at the end of the process of meiosis. Broadly, the meiosis cell division occurs in two steps - Meiosis I and Meiosis II, which again have their substeps. interphase The stages of Meiosis | are : ``` Prophase I Metaphase I Anaphase I Telophase I Cytokinesis I ``` The stages of Meiosis || are : ``` Prophase II Metaphase II Anaphase II Telophase II Cytokinesis II ```

Answer 437

Lysosomal storage disease Missing enzyme that breaks down lipofuscin • Accumulates in nerve cells, liver, kidneys and spleen • Progressive permanent loss of motor function • Decreased vision, dementia, seizures, balance problems • Affects border collies, Border Collies, Chihuahuas, Cocker Spaniels, Dachshunds, English Setters, & Salukis

Answer 438

Individual must receive two copies of the abnormal (recessive) gene • Asymptomatic carrier parents • 25% probability of offspring being affected • Breeding to remove from gene pool e.g myoclonic epilepsy There are five hallmarks of autosomal recessive inheritance: • Males and females are equally likely to be affected. • On average, the recurrence risk to the unborn sibling of an affected individual is 1/4. • It misses generations • Parents of affected offspring may be related. The rarer the trait in the general population, the more likely a consanguineous mating is involved. • The trait may appear as an isolated (sporadic) event in small sibships.

Answer 439

autosomal recessive disorder defective DIRAS1 gene frameshift mutation . The variant changes the last 10 amino acids of the normally 198 amino acids-long protein and produces a stop loss leading to a protein 104 amino acids longer than the wild-type

Answer 440

Polycystic kidney disease (PKD) in Persian cats One trait, 2 alleles A = dominant abnormal allele a = recessive normal allele Hallmarks of autosomal dominant inheritance 1. Every affected individual has an affected biological parent. There is no skipping of generations. 2. Males and females equally likely to inherit the mutant allele and be affected. The recurrence risk of each offspring of an affected parent is 0.5 3. Normal siblings of affected individuals do not transmit the trait to their offspring 4. The defective product of the gene is usually a structural protein, not an enzyme. • structural proteins are usually defective when one of the allelic products is non-functional; • enzymes usually require both allelic products to be non-functional to produce a mutant phenotype.

Answer 441

Males are always hemizygous for X linked traits, that is, they can never be heterozygotes or homozygotes. They are never carriers. A single dose of a mutant allele will produce a mutant phenotype in the male, whether the mutation is dominant or recessive

Answer 442

When the locus for a gene for a particular trait or disease lies on the X chromosome, the disease is said to be X-linked • The inheritance pattern for X-linked inheritance differs from autosomal inheritance only because the X chromosome has no homologous chromosome in the male, the male has an X and a Y chromosome • Very few genes have been discovered on the Y chromosome. • The inheritance pattern follows the pattern of segregation of the X and Y chromosomes in meiosis and fertilization • A male child always gets his X from one of his mother's two X's and his Y chromosome from his father. X-linked genes are never passed from father to son • A female child always gets the father's X chromosome and one of the two X's of the mother. An affected female must have an affected father Males are always hemizygous for X linked traits, that is, they can never be heterozygotes or homozygotes. They are never carriers. A single dose of a mutant allele will produce a mutant phenotype in the male, whether the mutation is dominant or recessive • On the other hand, females must be either homozygous for the normal allele, heterozygous, or homozygous for the mutant allele, just as they are for autosomal loci.

Answer 443

Mothers pass their X’s to both sons and daughters • Fathers pass their X to daughters only. • Normal outsider rule for dominant pedigrees for females, but for sex-linked traits remember that males are hemizygous and express whichever gene is on their X. • X D = dominant mutant allele • X d = recessive normal allele Families with an X-linked dominant disorder often have both affected males and affected females in each generation. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons; fathers only pass X chromosomes to their daughters and Y chromosomes to their sons

Answer 444

One individual has two or more populations of cells with different genotypes The sooner the mutation happens in developmet the bigger potentail fpr more cells to posses the trait in question

Answer 445

Post-replication mismatch repair further improves accuracy of dna replication it occurs when a mismathc is deteted in newly synthesised DNA the new DNA is cut and the mispaired nucleatide and its neighbours are removed and then replaced with the correct nuclueotide by DNA polymerase DNA ligase seals the gap

Answer 446

substitution, insertion or deletion | Alters sequence of bases within gene

Answer 447

section of DNA or RNA that runs from START codon to STOP codon ORF is read in triplets of bases (codons) from START codon onwards

Answer 448

One base in the DNA sequence changed to another base - Transcript affected too Missense mutation = mutated codon calls for incorrect amino acid. Nonsense mutation = mutated codon is now a stop codon. Silent mutation = amino acid sequence not affected Due to redundancy of code

Answer 449

mutated codon calls for incorrect amino acid.

Answer 450

mutated codon is now a stop codon.

Answer 451

amino acid sequence not affected | Due to redundancy of code

Answer 452

Inappropriate number of bases in a DNA sequence following mutation Affects entire reading frame of 3-letter codons after the point of change Frameshift mutation Potential catastrophic change in functionality of protein

Answer 453

Substitution of A for G at nucleotide 1477 Results in glycine instead of glutamic acid at position 379 Found in over 25 breeds of dog Milder than haemophilia A Sex-linked recessive trait Dogs should not be used for breeding

Answer 454

Autosomal dominant Renal cysts present in early life Slow progression to end-stage renal disease Point mutation in PKD1 gene on chromosome 3 No healthy carriers (affected cat has affected parent)

Answer 455

Presence or absence of trait is determined solely by genetics

Answer 456

Proportion of individuals with genetic variant (mutation) who exhibit signs and symptoms of genetic disorder

Answer 457

single gene

Answer 458

A substance or agent that causes DNA impairment that results in the alteration of the DNA sequence Mutagens can be physical, chemical or biological

Answer 459

``` UV light, x-rays etc. Directly damage DNA or nucleotides Induce cross-linking Break chromosomes Break DNA strands Delete bases Nucleotide dimers ```

Answer 460

Base analogs – structurally similar to nucleotides so get incorporated into DNA Base altering agents – induce methylation, alkylation, deamination of DNA bases Intercalating agents – similar structure to base pair heterocyclic ring

Answer 461

Transposons and insertion sequences Viruses Bacteria

Answer 462

Occur in gametes or in the reproductive cells that produce gametes Mutations are inheritable Transferred to the next progeny in all their cells

Answer 463

``` Bovine leukocyte adhesion deficiency (BLAD)- marked neutrophilia leucocytes cannot migrate into blood also seen in irish setters single point missesnse mutation anmals tend to die young ``` Hyperkalaemic periodic paralysis (HYPP) results in paralysis due to disruption of sodium ion channel adenine to gaunine substitution increses potassium in blood porcine stress syndrome- death, inability to walk, blanched apearence of carcus Missense mutation in ryanodine receptor gene X-linked tremours- shaking puppy syndrome Missense mutation in ryanodine receptor gene progressive fatal condition

Answer 464

Hereditary goitre in Afrikander cattle- Nonsense mutation in thyroglobulin gene effects some goats Bovine citrullinemia in Holstein-Friesian cattle- Nonsense mutation in argininosuccinate synthetase gene effects urea cycle- build up of amonia in blood lethal early in post natal period Deficiency of uridine monophosphate synthase (DUMPS Hypotrophic axonopathy in quail Maple syrup urine disease- in cattle Nanomelia- chickens connective tissue disorder

Answer 465

Occur in the non-reproductive cells (somatic cells) May not be manifested to affect an individual due to the reparative and compensative processes of the body. Somatic mutation that alters the cell division patterns of the cell can eventually result in the formation of cancerous cells or tissue

Answer 466

agents that can induce an effect on a fetus in eutero withot effect to the mother

Answer 467

Cellular metabolism comprises hundreds of enzymatic pathways with many steps Each step requires an enzyme or other protein with a particular function Each step is part of a cascade, inhibition etc. Non-functional protein stops the pathway Often results in accumulation of a product Product can have toxic effects

Answer 468

a type of genetic disorder primarily resulting due to alterations in one gene or as a result of abnormalities in the genome.

Answer 469

Clinical signs begin at 1 to 4 days ``` Apparent blindness Depression Head pressing Convulsions Terminal coma Death by 1 week ``` Urea cycle converts toxic ammonia to urea Each step carried out by specific enzyme Occurs primarily in the liver Urea excreted via kidneys Argininosuccinate synthetase (ASS) converts citrulline to argininosuccinate Comparison of ASS gene in affected and normal animals shows single base substitution Substitution of T for C in the first position of the 86th triplet codon CGA (arginine) becomes TGA (STOP) Polypeptide terminated at the 85th amino acid Biochemical detection of carrier status All heterozygotes have 50% ASS activity compared to normal animals Affected individuals have 0 ASS activity

Answer 470

Born with easily extendible or very fragile skin Ehlers-Danlos / dermatosparaxis / cutaneous asthenia Slight scratch can cause severe lacerations Collagen fibres formed from triple-helix pro-collagen Pro-collagen requires enzymatic modification to form mature functioning collagen More than one type of collagen Collagen one contains α-1 chains (x2) and α-2 chains (x1) Both are coded for by separate genes Type-1 procollagen becomes type-1 collagen through removal of terminal amino acids Mutations can occur in any of these genes: α-1 procollagen chain α-2 procollagen chain Procollagen I mutations in these genes are dominant disorders carboxy-proteinase (PCP-C-I) endopeptidase Procollagen I aminoproteinase (PCP-N-I) endopeptidase- THIS IS THE ONE THAT MUTATES IN CATLE AND SHEEP- recesive inherited disorder heterozygous effected animals still have enough enzyme Mutation in any of these will lead to the clinical symptoms of stretchy and fragile skin Genetically heterogeneiic ``` Dominant form in: Horses Cats Dogs Rabbit Recessive form in: Sheep Cattle ```

Answer 471

e.g ehlers danlos If a specific set of clinical signs arises from more than one mutation, there is genetic heterogeneity for that disorder If genetic heterogeneity is undetected it can be difficult to establish the form of inheritance if clinical signs have a genetic basis

Answer 472

``` Late-onset, autosomal recessive photoreceptor degeneration Starts with night blindness Progresses to total blindness Age of onset varies between breeds Puppies are born normal ``` PRCD (progressive rod cone atrophy) is one of several inherited diseases grouped under the progressive retinal atrophy (PRA) rubric Autosomal recessive disorder due to mutation in the Progressive Rod-Cone Degeneration (PRCD) gene Mapped to canine chromosome 9 Substitution of guanine with adenine Changes cysteine to tyrosine (C2Y) Genetic tests are available PRA causes retinal cells to degenerate and die Initially loss of rods then cone Ophthalmic evaluation may only take place after first clinical signs Electroretinography (ERG) is a very sensitive indicator of PRA Early diagnosis aids lifestyle adjustments

Answer 473

the combined effect of all factors (environmental and genetic), that render an animal more or less likely to develop that disorder Liability is continuous Classification is ‘normal’ or ‘affected’ Threshold allows classification

Answer 474

proportion of total variation in a trait that can be attributed to variation in genetic factors Relative importance of genetic and environmental factors Contribution of each to disease aetiology

Answer 475

The action of one gene depends on the action of another gene Coat colour: Different combinations of alleles from different loci Agouti (ASIP) gene causes hair pigment cells to switch from black/brown to yellow/white Expression of ASIP is driven by gene promoters Different promoter alleles drive different colour patterns- promoter region is part where polymerase enzyme binds to start expression controls when its expressed, where and for how long

Answer 476

Caused by multiple genes and influenced by environmental factors Inheritance is not always straightforward Lots of gene contribute to risk ``` Bell-shaped curve: Few individuals with all pre-disposing factors (genetic & environmental) Many with some factors (either, or both) Few with no pre-disposing factors Example of a multifactorial trait ```

Answer 477

Proportion of liability that can be attributed to genetics or Proportion of differences in liability that are a result of genetic differences among animals Most familial disorders have intermediate heritability Heritability for liability is usually greater than zero Selection for decreased liability can reduce incidence Non-genetic means can also alleviate inherited disorders

Answer 478

Common endocrine disorder Influenced by genetic factors Similar genes and/or genetic pathways in humans Destruction of pancreatic beta-cells No insulin produced Sugar cannot be absorbed into cells Blood sugar levels remain high Genetic basis Altered immune response- body attacks pancreas in autoimune response posibly on respone to pancrratitis or viral infection Environmental factors - things that cause pancrreatitis, high fat diet ect no type 2 diabetes found in dogs but is found in cats genetic factors assosiated with brain, thymus, pancreaus, lymphocyte activation ect diabetes mellitus

Answer 479

Type II is most common form Between 0.2 and 1% of cats will develop diabetes Risk factors include: - Obesity - Increasing age - Physical inactivity - Male gender - Use of steroids- from feline asthma ect- prolonged use

Answer 480

A polygenic trait is one whose phenotype is influenced by more than one gene ``` coat colour eye colour body shape dentition immunity height ect ``` behaviour- 131 single nucleotide polymorphisms associated with breed differences in behaviour Genes expressed in brain with neurobiological functions and developmental processes

Answer 481

liability imoortant here development of the joint is dictated by genes evelopmetn of the disease is influenced by feed level, dietery electrolites, level of exersise multifactoral trait Alleviating inherited disorders: Restricted feeding during growing phase (age of onset and incidence) Dietary electrolyte balance

Answer 482

the abnomal growth of cells It is an abnormal growth of cells that leads to a neoplasm (tumour) Neoplasia can occur in any tissue type in the body and in any body system Neoplasms can either be described as benign or malignant. The term ‘cancer’ is sometimes used to describe malignant neoplasms Neoplasia is the result of uncontrolled cell proliferation. DNA damage is very common and repair sometimes fails. Genetic mutations lead to increased cell growth (via mitosis) and decreased cell death (via apoptosis) Neoplastic cells are able to stimulate angiogenesis. New vascular tissue grows into the mass to nourish the ever growing mass of cells. Further mutations allow invasion and metastasis in malignant neoplasms

Answer 483

each checkpoint is controlled by protiens that control the progression of a cell through the cycle: Stimulating proteins (encoded by proto-oncogenes)- enhance cell division and inhibit cell death- CDK-cyclins ``` Inhibitory proteins (encoded by tumour suppressor genes)- control cell division and simulate cell death- P53 tumour suppressor ```

Answer 484

Stops progression through G1 to s phase if DNA is damaged stalls cell cycle Allows cell time to repair DNA If irreparable, triggers apoptosis mutation can lead to cancer

Answer 485

cytokine dependent kinases Enzymes that activate or inhibit other proteins via phosphorylation Can activate proteins that stimulate cell cycle progression once cyclin concentration reaches threshold mitosis is triggered mutation can lead to cancer

Answer 486

DNA repair protiens

Answer 487

mutated proto-oncogene that stimulates cell division and proliferation

Answer 488

creation of new blood vessels to support growth and spread of cancer normal process outside the process of cancer Angiogenesis is regulated by competing pro and anti‐angiogenic signalling The transition to a pro‐angiogenic status occurs when anti‐angiogenic signalling is overwhelmed Tumour cells secrete growth factors to stimulate blood vessels

Answer 489

presence of abnormal cells within tissue or organ- eg abnormal structure of nucleus, structure of DNA

Answer 490

Malignant tumours of epithelial origin

Answer 491

Malignant tumours of mesodermal origin

Answer 492

normal mucosa> hyperplasia> dysplasia > carsinoma in situ> invasive carcinoma

Answer 493

increase in tissue or organ size due to cell proliferation- possible mutation in cell cycle

Answer 494

``` Tend to grow slowly Expansive, but well circumscribed Often encapsulated Cells are well differentiated i.e. closely resemble the tissue of origin Few mitotic figures (slower growth rate) Do not metastasise ```

Answer 495

Benign tumour of adipose cells | Common in subcutaneous tissues of older, obese animals

Answer 496

Benign tumour of glandular epithelial tissue | Perianal adenoma commonly seen in older entire male dogs

Answer 497

Rapidly growing benign tumour of round cells Commonly seen in young dogs on the face and limbs Can spontaneously regress with T cell invasion

Answer 498

Benign wart-like tumour of epithelial cells Often seen in oral cavity and on lip margins, eyelids, ears Papilloma virus: develop warts 1-2 months post infection

Answer 499

Benign tumour of fibrous connective tissue Biopsy required to distinguish from malignant form Often caused by poxvirus or papillomavirus infections

Answer 500

``` More rapid growth Invasive and infiltrative Non encapsulated Cells are anaplastic – do not resemble tissue of origin Many mitotic figures (rapid division) Metastasise ```

Answer 501

malignant tumours: Squamous cell carcinoma Transitional cell carcinoma Adenocarcinoma

Answer 502

Commonly found on ear tips or in oral cavity | On skin: associated with exposure to UV light

Answer 503

Found in the urinary tract, commonly bladder

Answer 504

``` Malignant tumour of glandular tissue e.g. mammary glands Mammary tumours in dogs The most common neoplasia of the bitch Caudal glands most commonly affected Highly malignant, metastasise readily ```

Answer 505

``` malignant tumours: Fibrosarcoma Osteosarcoma Feline injection site sarcoma Lymphosarcoma Hemangiosarcoma ```

Answer 506

Malignant tumour of fibrous tissue | Often invasive

Answer 507

Malignant tumour of osteoblasts Common in large breed dogs Away from the elbow/towards the knee

Answer 508

Mainly associated with inactivated rabies and FeLV vaccines | Exact aetiology unknown by likely stimulation of inflammation from repeat injections

Answer 509

Malignant tumour of lymphoid tissues | Some cases in cats associated with FeLV infection

Answer 510

``` Malignant tumour of endothelial cells Can affect Skin Spleen Liver Heart Bone Kidneys, bladder, lungs… ```

Answer 511

Malignant tumour in dogs arising from mast cells, usually affects the skin Contain histamine, highly reactive when irritated by handling/FNA/biopsy Some can be cured by surgical excision (low grade)

Answer 512

Neoplastic hematopoietic cells in peripheral blood or bone marrow Leukemia represents less than 10% of hematopoietic neoplasias in dogs and around 15-35% in cats. Besides FeLV infection in cats, there is not any other proven etiology for leukemia in small animals Cell lineage identification is an important step in the classification of leukemia

Answer 513

Type of plasma cell neoplasm originating from terminally differentiated B lymphocytes that have undergone malignant transformation Most important plasma cell neoplasm which results in diffuse disease Accounting for less than 8% of all hematopoietic tumours in dogs No breed or sex predilections exist, and older dogs are most commonly affected, with a mean age of 8 to 9 years

Answer 514

When malignant cells of the original tumour transfer to another part of the body an invasive phenotype is aquired cells invade the surounding stroma and then enter the hematogenous circulation they travel to a distant organ and invade they then adapt and proliferate to form metastases

Answer 515

Evolution of tumour to form different clonal stem cell lines Additional mutations Selection pressures treatment of a cancer can be a heterogenis selection pressure

Answer 516

Most commonly spreads to organs with large blood supply | Liver and lungs, also skin/bone

Answer 517

Spread through the lymphatic drainage system and seed in lymph nodes remove lymphnodes to treat and prevent

Answer 518

Spread to neighbouring organ by direct contact e.g. liver and spleen

Answer 519

Exfoliation of tumour cells into a cavity or another site e.g. incision site can occur becuase of surgery via instruments

Answer 520

``` sustained proliferative signalling activating invasion and metastasis evading growth supression inducing angiogenisis enabling replicative imortality resisting cell death ``` underlying hallmarks (driving factors)- genome instability and mutation tumor promoting inflamation deregulating cellular genetics- reprograming energy metabolism avoiding imune distruction all targets for cancer treatment

Answer 521

Imaging techniques can be a useful aids to locate abnormal growths however they give no information about the type of growth The most helpful aid to diagnosis is to take a biopsy. Histopathological examination will enable definitive diagnosis and allow grading of the tumour to determine its degree of malignancy. ``` Collection of the sample Fine needle aspiration Impression smear Biopsy: Needle core biopsy Bone marrow biopsy Punch biopsy Wedge biopsy Excisional biopsy Processing of the sample: Cytology Histopathology (formalin) ```

Answer 522

Paraneoplastic syndromes Hypercalcaemia – adenocarcinoma, lymphoma, multiple myeloma Hypoglycaemia – insulinoma, hepatic tumours Coagulopathy – hemangiosarcoma, MCTs, thyroid tumours Changes in blood pressure Hyperviscosity – multiple myeloma, lymphoma ``` Other complications Anaemia - through myelosuppression or haemorrhage Ulceration and infection Weight loss and cachexia Obstruction Histamine release - MCTs ```

Answer 523

``` Surgery Radiotherapy Chemotherapy Cryotherapy Hyperthermia Photodynamic therapy Adjunctive therapies ``` more often palliative

Answer 524

yeast- can rapidly provide information about aspects of cellular ageing roundworms- live only 2-3 weeks, allows mutations relating to lifespan to be identified Fruit flies-commonly used. extremely effective tool for studying evolutionarily conserved aspects of ageing. additional interactions at play within and between tissues of a multicellular, differentiated, organism (such as insulin signalling pathway) can be modelled in worms and flies. When combined for their individual experimental strengths, flies can function as an effective pipeline of discovery of evolutionarily conserved interventions to enhance lifespan, which can be targeted for experiments in the longer-lived vertebrate systems, such as mice (approx. 3y) and rats (approx. 3y). Drosophila- convinient,easy husbandry, distinct tissues with human equivilents that can be genetically manipulated rodents- more closly related to humans. cost effective, convinient, Mice are better models than flies or worms for studying complex biological systems found in humans, such as the immune, endocrine, nervous, cardiovascular and skeletal systems - like humans, mice naturally develop diseases that affect these systems, including cancer and diabetes. non-human primates- allows the integrated system of genes to be studied. rhesus monkey, common marmoset. similar aging process to humans birds- high metabolic rates body temperatures and blood sugar levels, and yet some species are among the most long-lived of all animal species. birds have mechanisms to protect them from oxidative damage and that they can regenerate certain neurones in the brain

Answer 525

Ageing in both human and yeast cells is not only the result of passive wear and tear, it is also caused by an active process orchestrated by a distinct set of genes, some of which slow down ageing while others speed it up. For example, by exposing yeast to lithocholic acid (an ageing-delaying natural molecule) scientists created long-lived yeast mutants that they dubbed “yeast centenarians.” These yeast mutants lived five times longer than their normal counterparts because their mitochondria consumed more oxygen and produced more energy than in normal yeast. The centenarians were also much more resistant to oxidative damage – a key process that causes ageing.

Answer 526

enes that regulate metabolism in the roundworm and affect lifespan. The roundworm genes that seem to confer increased longevity do so by supporting resistance to external stresses, such as – Bacterial infections, High temperatures, Radiation, Oxidative damage (oxidative damage results when the toxic by-products of oxygen metabolism damage the components of cells).

Answer 527

significant research in roundworms has focused on the gene that regulates the activity of a particular type of protein, co-enzyme Q7, hydroxylase (COQ7) that plays a crucial role in electron transport within mitochondria that produce energy. Investigators have discovered that mutations that diminish COQ7 lead to a modest increase in life span. These mutations have a bigger effect when combined with other mutations, such as those in the insulin pathway and affect resistance to oxidative damage.

Answer 528

research has studied a variant of roundworms that possess a mutant gene labelled DAF-16. These mutant worms carry large amounts of DAF-16 in their nuclei, which cause the worms to live longer than worms without an excess of DAF-16.

Answer 529

Past research on the Insulin Signalling (ISS) and TOR pathways shows that altering certain genes, usually yields a 100% and 30% lifespan increase, respectively. The assumption was then, that altering them together would boost lifespan by 130%, however when scientists tested this they found that the effect was much greater than the sum of its parts.

Answer 530

``` Disorientation Social Interactions Sleep-wake cycles House-training Activity ``` Codes for presence over severity. ccds Quick and easy.

Answer 531

``` Four symptom clusters: Spatial orientation Social interaction Sleep–waking cycle House soiling ``` each section cored from 0 to 5 points based on frequency and then added to form an acumulative score allows dog to be graded on cognative disfunction

Answer 532

Atrophy (shrinkage) of tissue in some regions Increased ventricular volume Loss of neurons and synapses and reduced formation of new neurons Accumulation of abnormal proteins decline in glucose metabolic rates in the brain chemical loss- degeneration of neurons that provide neurottansmitters, eg dopamine,acetylecholine

Answer 533

Dopamine cells located in the Ventral tegmental area (VTA) and Substantia nigra (SN). Three main projections: Mesocortical Mesolimbic- reward Mesostriatal regulates behahviour, emotion learning Dopamine cells are limited in supply. Less than 50,000 Degenerate easily during ageing. Degeneration linked to mechanisms to compensate for failed function. Balance of degeneration vs chemical compensation.

Answer 534

Acetylcholine cells located in the Medial septal nucleus (MSN), Nucleus basalis (NB), and Tegmental nucleus (TN). Three main projections: Frontal Septal Basal plays role in memory loss degenerate easily but more prone to enviromental factors than other neurones

Answer 535

Active ingredient is Selegiline Hydrochloride. Inhibits monoamine oxidase B. ensures higher levels of dopamine ``` Low dose (sub 20mg per Kg) Increased dopamine levels ``` ``` High dose (20mg per Kg) Increased dopamine, serotonin and noradrenaline. ``` Selegiline is a selective MAO-B inhibitor at low doses. Prevents breakdown of dopamine therefore increasing levels in the brain. At high doses inhibits MAO-A. Prevents breakdown of noradrenaline and serotonin increasing levels in the brain. Counter indicated with selective serotonin reuptake inhibitors (SSRI’s)

Answer 536

Active ingredient is Propentofylline. Inhibits phosphodiesterase (PDE) and adenosine reuptake transporters. Low dose (6mg per Kg) High dose (10mg per Kg) Propentofylline inhibits phosphodiesterase (PDE) and adenosine reuptake transporters. Increases adenosine signalling and nitric oxide production. Significant vasodilation affect, resulting in increased cerebral blood flow.

Answer 537

vitamine B, D and E Flavonoids-improve blood vessel function and communication between nerve cells Fish Oils

Answer 538

Muscular dystrophy (MD) is a progressive fatal disease characterized by degeneration of skeletal and cardiac muscle Most common form is Golden Retriever MD (GRMD) Also seen in rottweiler; pointer; beagle and others phenotypic variability due to differencec in muscle metabolism Characterised by degeneration of skeletal and cardiac muscle Affected individuals exhibit atrophied muscles Seen early in life (1 month) – often ineffectual sucklers effects dystrophin gene ``` clinicla signs: Stiff gait Decreased agility Decreased exercise tolerance Muscle atrophy Prominent bones along spine, ribs and skull Megaoesophagus Large tongue Excessive drooling ``` diagnosis: Elevated creatine kinase in bloodwork Muscle biopsy Histopathological examination of muscle tissue Degenerating muscle fibres Changes in diaphragm and heart observed during necropsies genetic test

Answer 539

Defect in a gene on the X chromosome X-linked recessive disorder Higher prevalence in males as they only have one X chromosome Males are always hemizygous for X linked traits Females must receive two copies to display GRMD phenotype Gene is responsible for production of dystrophin Very long gene product Very large protein mutation is on splicing site substitution results in exon not being recognised as exon and is removed results in frame shift and new stop codon created protien loses regions that interact with sarcolema

Answer 540

Dystrophin acts as a shock absorber Connects the actin cytoskeleton to the extracellular matrix Each end of the molecule is tailored to interact with cytoskeleton or glycoproteins Mitigates any damage in muscle when muscle cells contract transferes force of muscle contracts from insidd to outside sarcolema becomes weaker with every muscle contration without it reaulting in leaky muslce cells and subsiquently degeneration Reduced membrane integrity allows enzymes such as creatine kinase (CK) to leak out Calcium influx leads to protease activity Results in muscle abnormalities and necrosis Stimulates inflammation and further muscle damage Muscles deteriorate with loss of myofiber membrane integrity muscle is repalced with connective tissue and fat eventualy effecting cardiac and respiritory muscle

Answer 541

Most common cutaneous tumour in horses. Prevalence 04-15.8% Non life threatening but big effect on welfare and material value of the horse Pre-purchase examination! Exclusion from insurance coverage Infection of the site Diffulties defecating, urinating, mastication, locomotion Tack issues Prevalence is higher in younger horses (as early as 6 months and the average is 3.5-4 y.o) Genetic predisposition: equine major histocompatibility complex (MHC) is encoded in the equine leucocyte antigens (ELA) in chromosome 20 ELA haplotypes A3 and B1 higher susceptibility But… not all B1 horses suffer sarcoids! Markers in chromosomes 20, 22, 23 and 25 identified

Answer 542

Occult, verrucose, nodular (types A1, A2, B1 and B2), fibroblastic (types 1a, 1b and 2), mixed and malignant

Answer 543

most benign form of ES and are thought to represent an early stage of the disease. Occult sarcoids are often circular alopecic lesions with a grey colour, that lack hair and their appearance is of a hyperkeratotic dry lesion. On palpation, skin feels thickened, dry and has small nodules underneath. This form is easily misdiagnosed as ‘ring-worm’ (dermatophytosis) or skin rubs from tack or other equipment

Answer 544

prominent from the skin and they are similar to warts in appearance. The skin on these lesions is dry, alopecic and scaly. The margins are not well defined. Due to the ‘wart-like’ appearance these can be mistaken for equine papillomas.

Answer 545

are circumscribed firm subcutaneous masses that can appear as single or multiple lesions. Type A are characterised by no skin involvement (the skin can be freely moved over the nodules). If the underlying tissues are not involved it is classified as nodular type A1 and if there is deep tissue involvement it is named A2 Nodular type B sarcoids are nodular sarcoids with visible and palpable skin involvement. When they have defined margins they are classified as B1 and if they have ill-defined margins they are named B2

Answer 546

Fibroblastic tumours have a ‘fleshy’ appearance aggressive form of sarcoids and have a tendency to ulcerate and become infected. Fibroblastic pedunculated sarcoids have a clear margin and a ‘neck’ that separates the lesion from healthy skin. Depending on deep tissue involvement, fibroblastic pedunculated sarcoids are classified as type 1a with no deep tissue involvement, and type 1b with deep tissue involvement Fibroblastic sessile sarcoids on the other hand have ill-define margins, a broader base and there is always involvement of underlying tissue. It can become difficult to macroscopically differentiate any of the fibroblastic sarcoids from fibrosarcoma and squamous cell carcinoma in which case biopsy will be recommended

Answer 547

Malevolent equine sarcoids sometimes called malignant, are rarely described in the literature. The tumour infiltrates the lymphatic system and the progression is fast. It affects extensive areas and it may comprise different clinical types of ES.

Answer 548

relatively common tumour in dogs that develops from pigment-producing cells (melanocytes) This tumour is generally malignant, in that it will grow to invade surrounding tissue, and, more importantly, may spread elsewhere within the body, particularly to the nearby lymph glands (lymph nodes) and the lungs. Most tumours in the mouth and many tumours of the nail bed are malignant, whereas many tumours arising from haired skin and within the eye are benign. A diagnosis of melanoma is made by a pathologist examining a piece of tissue under the microscope.

Answer 549

acute states dramatically respond to systemic administration of the deficient nutrient or metabolite accurate and rapid diagnosis is important Ideally, diagnostic tests can be used to predict the occurrence of disease. Pathogenesis of each disease is primarily related to alterations in metabolism. In most cases, the basis of disease is from an increased demand for a specific nutrient that has become deficient under certain conditions. Diseases are augmented by management practices directed toward improving and increasing production. considered production diseases. also metabolic diseases because management of the animal is directed at production, hypocalcemia hypomagnesimia hypoglycemia milk fever of cows occurs when the mass of calcium in the mammary secretion is greater than the cow’s diet or its skeletal reserves can supply.

Answer 550

``` concentrations in the body higher than 50 mg kg-1 BW calcium, phosphorus, potassium, sodium, chloride, Magnesium sulphur, ``` The structural function involves elements that build organ and tissue structures calcium, magnesium, phosphorus, silicon in bones and teeth, phosphorus and sulphur in muscle proteins. The physiological function is responsible for the supply of electrolytes to body fluids and tissues in order to regulate osmotic pressure, maintain the acid-base balance, regulate membrane permeability and nerve impulse transmissions sodium, potassium, chloride, calcium, magnesium. The catalytic role of minerals is probably the most important function. Macronutrients and micronutrients act as catalysts in enzyme and endocrine systems; coenzymes to initiate enzyme and endocrine functions, constitute integral and specific structural elements of metalloenzymes and hormones. mineral elements are also responsible for cell replication and differentiation. Zinc influences transcription, iodine is a component of thyroxine (a hormone responsible for thyroid function and energy processes)

Answer 551

concentrations in the body below 50 mg kg-1 BW. ``` iron, iodine, zinc, copper, manganese, cobalt, molybdenum, selenium, chromium, tin, vanadium, fluoride, silicon, nickel arsenic ``` The structural function involves elements that build organ and tissue structures calcium, magnesium, phosphorus, silicon in bones and teeth, phosphorus and sulphur in muscle proteins. The physiological function is responsible for the supply of electrolytes to body fluids and tissues in order to regulate osmotic pressure, maintain the acid-base balance, regulate membrane permeability and nerve impulse transmissions sodium, potassium, chloride, calcium, magnesium. The catalytic role of minerals is probably the most important function. Macronutrients and micronutrients act as catalysts in enzyme and endocrine systems; coenzymes to initiate enzyme and endocrine functions, constitute integral and specific structural elements of metalloenzymes and hormones. mineral elements are also responsible for cell replication and differentiation. Zinc influences transcription, iodine is a component of thyroxine (a hormone responsible for thyroid function and energy processes)

Answer 552

Mineral deficiency can impair or inhibit metabolic pathways required for normal body function Severe macroelement or microelement deficiencies symptoms corresponding to the function of the deficient element in the body accurate diagnosis Minor deficiency, the symptoms are non-specific, often transient difficult to diagnose. Frequently occur ``` Mineral deficiency generally leads to impaired immunity, inhibited growth, reproductive disorders lower productivity ``` Mineral deficiencies can result from low quality feed, impaired absorption or assimilation increased demand for minerals

Answer 553

disruption of Calcium homeostasis What is calcium involved with normally? ossification, blood coagulation, milk, cardiac rhythm control, cell membrane permeability and linkage between cells, nerve and muscle excitation, activation and secretion of hormones through exocytosis and activation of enzymes. Structural integrity of teeth and bones…………… Where does it come from-food! (Stored and released from bones). The major absorption site of Ca in the gastrointestinal (GI) tract of ruminants is the small intestine Major increase in requirement-start of lactation, have to meet that demand. The severity and duration of a hypocalcaemic event depends on the integrity of the cows Ca homeostasis mechanisms. Plasma calcium is distributed in 3 major fractions: About 50% of total plasma Ca is bound to negatively charged sites on proteins, such as albumin. parasites can decrese albumin levels and have knock on effect Free calcium. Between 42-48% of total plasma Ca is present as free ions in plasma. This is the portion of total Ca that is hormonally regulated and which contributes to certain Ca-associated pathological states. About 5-8% of total plasma Ca is bound to non protein anions What happens physiologically 99% is in the bone in the form of hydroxyapatite crystals. The next largest pool of calcium is intracellular calcium. In the inactive cell state, calcium concentrations are relatively low in the cytosol; calcium is bound to proteins or contained within the mitochondria or granules of the endoplasmic reticulum. Calcium concentrations are indicative of cell activity. How much? Blood Ca in the adult cow is maintained around 2.1-2.5mmol/L 3g Ca in the plasma pool 8-9g in all compartments outside of the bone in a 600kg cow. The smallest pool of calcium, which resides in the Extra Cellular Fluid (ECF), is the most important pool for physiological control of calcium concentrations in the blood. This component comprises interstitial calcium, blood calcium and a small (0.5%) but important part of the bone calcium pool, which exists as amorphous crystals or in solution. The soluble bone calcium pool allows access to the large reserve of calcium that resides in bone. The regulation of calcium levels involves control of the movement of calcium between the ECF and three body organs: bone, GI tract and kidneys (less so in ruminants due to the contributon of the salivary glands). The exchange of calcium ions Fluid within the canaliculi of the bone may contain another 6-15g Ca; dependant on the acid base status of the animal Around 50% of the total plasma calcium is bound to proteins (primarily albumin), with another 5% bound to organic compounds in the blood, such as citrate. From 42-48% of the total plasma Ca exists in the ionised, soluble form (Ca2+), the amount being closer to 48% at low blood pH and closer to 42% at elevated pH. As the pH of blood becomes acidic, the calcium ions (Ca2+)will increase due to the competition of hydrogen ions (H+) for binding to the negatively charged site on serum proteins. During the dry period, Ca requirements are minimal 10-12g/day. At parturition -sudden increase in cows Ca requirements. A dairy cow producing colostrum or milk needs to withdraw 20-40g Ca from her pools each day. not available in the plasma pool withdrawer calcium from bone or increase the rate of absorption of dietary Ca. these processes may take 2-3days to become fully active and if they fail, hypocalcaemia results. In common with their other homeostatic controls, all ruminants are able to regulate with strict precision the concentration of Ca in plasma, under the influence of three hormones: parathyroid hormone (PTH), calcitonin (CT) 1,25-dihydroxyvitamin D 3 (l,25(OH) 2D3 ). (1,25-DHD) In principle PTH and 1,25-DHD increase blood calcium, where as calcitonin decreases it. Calcium metabolism from bone is less rapid: in older cows in cows fed pre-partum diets high in Ca. So a sudden and large increase in loss of Ca from the extracellular pool can result in hypocalcaemia before the Ca homeostatic mechanisms can act. Calcitonin is secreted by cells in the thyroid gland, principally in response to Ca concentrations in blood and extracellular fluids. Calcitonin and PTH act in together to provide a negative feedback mechanism to maintain the concentration of Ca in extracellular fluids within narrow limits. The major inhibitors to PTH synthesis and secretion (stimulated by elevated Ca in blood) are calcitonin and 1,25-DHD.

Answer 554

dietary potassium, high rumen nitrogen low dietary phosphorus.

Answer 555

Where is there low calcium-blood What do we see clinically: blood coagulation (enzymes) cardiac rhythm control-tachycardia cell membrane permeability and linkage between cells, nerve and muscle excitation-lack of smooth and skeletal muscle contraction Recumbent/paresis of limbs&neck, no uterine involution, RFM cannot swallow, cannot urinate, cannot ruminate/eructate (become bloated), teat sphincter cannot close Reduced activation and secretion of hormones

Answer 556

Mg absorption from the rumen-variable, mostly due to intakes, Surplus is rapidly compensated for -excretion by the kidneys. Small reductions in blood Mg may impair the capacity to mobilise Ca in response to hypocalcaemia. Low magnesium status (hypomagnesaemia) affects Ca metabolism by Reducing PTH secretion in response to hypocalcaemia Reducing the ability of PTH to act on its target tissues Interfering with the hydroxylation process of vitamin D3 in the liver. Magnesium absorption from the rumen is dependent on the concentration of Mg in solution in the rumen fluid the integrity of the Mg transport mechanism (Na+ linked active transport process). High dietary K+ reduces Mg absorption from the rume

Answer 557

ones and muscles are the main magnesium pools in the body. Magnesium has major roles in physiological processes and cellular metabolic pathways The ability of magnesium to stabilize cell membranes is one of its most important functions . Magnesium and calcium remain in a dynamic equilibrium Mg plays a significant role in the secretion of the hormone for calcium homeostasis and the responsiveness of tissues to hormones. It is estimated that more than 75% of hypocalcaemia cases seen in mid-lactation are due to inadequate dietary Mg supply Magnesium (Mg) is the second most abundant intracellular cation in mammals after potassium. Bones and muscles are the main magnesium pools in the body. Magnesium plays vital roles in nearly all physiological processes and participates in many cellular metabolic pathways. -It activates nearly 30 enzymes and participates in the metabolism of carbohydrates, nucleic acids and proteins. -Magnesium stabilizes DNA structure and influences RNA transcription as well as the formation of ribosomal subunits. -The presence of Mg2+ ions is required in all processes involving ATP. -The ability of magnesium to stabilize cell membranes is one of its most important functions (Soetan et al. 2010). Magnesium and calcium remain in a dynamic equilibrium, Mg plays a significant role in the secretion of the hormone that controls blood calcium and the responsiveness of tissues to that hormone. It is estimated that more than 75% of hypocalcaemia cases seen in mid-lactation are due to inadequate dietary Mg supply and a higher intake of magnesium than calcium can stilt the bone growth (Zimmermann et al. 2000). Magnesium improves potassium absorption and protects cardiac muscle cells and neurons against free radicals and toxic substances. It activates classical and alternative complement pathways (McCoy, Kenney 1992).

Answer 558

In adult ruminants, particularly in animals fed fast growing grass with low Mg content High levels of potassium (application of potash fertilisers) disrupt the absorption of magnesium. High levels of ammonia (from nitrogenous fertilisers) inhibit magnesium absorption. low in fibre and increase the rate of passage of food material through the rumen reducing time for Mg absorption. Reduced food intake e.g. due to bad weather or transportation. Hypomagnesaemia doesn’t correlate well with clinical signs, even a minor magnesium deficiency can lead to reduced dry matter intake, nervousness, a reluctance to be milked or herded, reduced milk fat and yield nerve and muscle excitation (aggressive!!), incoordinated movements, hyperexcitability, muscle spasms and seizures (chomping of jaws and frothy salivation) further drop in Mg concentrations increases the risk of hypomagnesemic tetany and death

Answer 559

``` Progressive degeneration of the joint Inflamitory disorder Pain and stiffness in joints Degeneration of carilage Hypertorphy of bone at margins Changes in synovila membrane Formation of bony outgrowths at joint Age relataed changes in skeletal system combined with injury ``` Stiff gaiute Joint pain Sensitive legs Loss of joint space Osteophytes Subchondral cysts Subchondral sclerosis Risk factors: Genetics * Joint alignment * Injury * Activity level * Obesity Treatment: Lifestyle advice (weight loss, activity level, diet etc.) * Pain relief (NSAIDs; corticosteroids; fluid modifiers) * Surgery (joint fusion; replacement; amputation) Outlook: OA is a non-curable, progressive, degenerative condition * Pain relief is key outcome * Major cause of euthanasia due to quality of life

Answer 560

Carilage lost-Exposure of underlying bone Formation of oseophys and subcondral bone cysts Joint space lost and bones rub toghter Articular cartilage degradation and synthesis destabelises- chondrochtes maintainds EXM Chondrocytes however have limited potential for replication do when damaged it is hard to recover Link to aging- osteoarthritis is linked to aging due to decreased cellular synethesnse, this esspecially effects condrocytes due to the low potentail for replication Senescent manifest dramatic changes in what they secret, proinflamitory secretions contribute to ectracellular matrix decline Stem cell decrease Altered intracellular communication- pro inflammatory tissue damage Summary, Arrest of cell cycle * Necrosis of chondrocytes * Release of degradative enzymes * Breakdown of ECM * Release of proinflammatory cytokines- from break down of ecm, bones rubbing and senesence secrerory changes

Answer 561

water belly, green muscle disease, green leg, spots on liver

Answer 562

c.ovis- tapeworm

Answer 563

c.bovis- muscle | TB lesion- lymphnodes, liver, heart, lungs

Answer 564

absesses (up spinal cord)- from tail bite, fighting, stress

Answer 565

same as lambs | look emaciated

Answer 566

a method to cut the carotid artery and jugular vein the carotid is cut for the pumping action to increase blood loss jugular is cut to starve brain of oxygen

Answer 567

pale, soft and exudative | can result in carcus form stress

Answer 568

Observations The OV must observe each animal (except poultry) moving and at rest. The inspection must be sufficient to identify animals showing neurological symptoms, respiratory symptoms, alimentary tract abnormalities, change in gait, or external abnormalities. Initial check Routine ante-mortem inspection may begin with an initial check done by the MHI. Where a suitably trained MHI assists the OV in carrying out the initial check, the OV should subsequently observe all the animals interacting with each other in their pens during ante-mortem inspection. The initial check, if undertaken by the OV, may suffice as to constitute an adequate ante-mortem inspection. Clinical inspections In addition to routine ante-mortem inspection, the OV is required to carry out a clinical inspection of all animals which do not appear to be ‘normal’ and those that the FBO or an MHI may have put aside To be able to carry out satisfactory ante-mortem inspections, clinical inspections and detailed examinations, the OV must have available the following facilities and equipment: adequate lighting adequate space adequate access adequate separate facilities for detailed examination (a crush or equivalent is desirable but not legally required – the OV should arrange suitable facilities with the FBO) isolation pen(s) for suspect animals with separate drainage and situated as to avoid contamination of other animals (not needed in all establishments) staffing assistance (for handling or restraint) sufficient time proper equipment, for example, thermometer and stethoscope The inspection must take place within 24 hours of arrival at the slaughterhouse and less than 24 hours before slaughter. In some cases, ante-mortem inspection may need to be repeated. The OV may inspect the animal(s) at any other time. Animals are inspected before they are slaughtered to: Identify any clinical signs of disease (e.g. Tetanus, rabies, poisoning): Could be transmitted to humans (ZOONOSES) or other animals (e.g.Anthrax, Foot and mouth disease) Make the meat unfit for human consumption Identify animals which have had medications Identify injured animals

Answer 569

With large animals, stunning is important to immobilize the animal to facilitate severing the blood vessels (sticking) to kill it. Operator safety would be severely compromised by trying to stick a conscious animal unless it was fully restrained. Manual restraint is feasible for small animals like sheep but not for cattle. Restraint in specially designed pens is a feature of Jewish slaughter in high throughput plants in Europe and North America. The stunning process must render the animal insensible immediately, or if it is not immediate, the process must be completely pain and stress free. By relaxing the body, some stunning techniques may also benefit carcass quality. There are different ways in which animals can be stunned. The first is use of a mechanical instrument (captive bolt pistol, percussion stunner or free bullet) which traumatizes the brain so that the animal loses consciousness instantaneously. The second is use of an electrical current passed through the brain. The third is the induction of unconsciousness by immersion in an anaesthetic gas such as carbon dioxide.

Answer 570

``` Tonic phase (lasts 10– 20 s ) Effective percussion stunning leads to the animal immediately collapsing, stopping rhythmic breathing and becoming rigid with head extended- stunning should be done in this phase ``` The position of the eyeball is fixed. Clonic phase Period of involuntary kicking movements of its legs (the). Gradually the animal relaxes- sticking should not procede at this phase

Answer 571

The carcass and viscera are inspected as soon as possible after slaughter. As in ante-mortem inspection, this is to identify abnormalities or disease that would make the meat and edible offal unfit for human consumption. To this end it is important that the carcass retains its identity with the parts and viscera removed from it. by synchronized parallel line systems. Inspection is normally carried out by specially licensed veterinarians or meat inspectors. As well as inspection, they will often have other roles, including overseeing animal welfare and hygiene standards. have characteristic lesions. Tissues and organs are examined by visual inspection palpation incision Considerable attention is paid to routine incision of lymph nodes to detect disease states. In infection, bacteria collect in the lymphatic system and are concentrated and destroyed in the lymph nodes. In disease they become swollen and abnormal in colour. Conditions such as pneumonia and tuberculosis

Answer 572

Causes abortion in sheep Found in variety of mammals, birds, fish Commonly found in: Raw and RTE meats and poultry, dairy products, raw vegetables, raw seafood and cooked seafood salads Growth range -1°C to +45°C “Ubiquitous” in the environment (decaying vegetation, soil, animal feed, sewage, water) Affects susceptible populations = high mortality rate (~30%)

Answer 573

Predominantly associated with cattle faeces Associated internationally with: Raw and undercooked red meats Raw milk Vegetables, sprouted seeds, unpasteurised fruit juices Untreated water Survives acidity to pH 3.6 Very low infective dose Can cause kidney failure (HUS) and death in at-risk groups

Answer 574

``` All salmonellas (>2200) presumed pathogenic “Enteric” origin – animals & birds ``` Historically associated with: Raw eggs, poultry, meat & meat products Has caused outbreaks internationally: Almonds, tahini, tomatoes, melons & pawpaws, juices, sprouted seeds Inadequate cooking also a factorq

Answer 575

``` Common commensal adapted to intestinal conditions Raw poultry (including offal) Raw milk and meat Untreated water Occupational exposure Low infectious dose ~500 cells Many cases, few outbreaks… Shows seasonality trends Is it more robust than we think? ```

Answer 576

Faster Greater scale Cheaper miniturised high-throughput parralled sequencing technology

Answer 577

whole genome sequencing

Answer 578

Compare the genomes of healthy and sick individuals Genetic factors contributing to disease Candidate genes The more individuals we compare and the greater the depth of analysis the better

Answer 579

Observational study (non-candidate-driven) Compares variants across entire genome in different individuals Is a variant associated with a trait? Participants classified by clinical manifestation Variant more common in those with disease? Variant associated with disease? Risk allele Data-driven approach to medicine Drug and diagnostic development Prognostic accuracy Personalised medicine (tbc)

Answer 580

Version of a gene that is associated with higher incidence of disease trait

Answer 581

When the number of copies of a specific segment of DNA varies among different individuals EG. do cancer patients have a higher incidence of this gene than others

Answer 582

Region of DNA identified to be associated with a particular phenotypic trait

Answer 583

: A gene believed to be related to a particular trait or phenotype. Suspected due to genomic location or known function

Answer 584

The sum of an individuals phenotypic traits (phenotypes of cells, tissues, organs and organism)

Answer 585

After a susceptible dog has oronasal exposure to secretions containing a CPV-2 virus the organism infects lymphoid tissue and induces viremia for 1 to 5 days. CPV-2 preferentially infects rapidly dividing cells of multiple tissues- calls that replace constantly- gut cells, bone marrow Villus blunting of the crypt epithelial cells results in decreased absorption, inflammation, and necrosis. This is responsible for the classic signs of vomiting and diarrhoea, the latter of which frequently contains blood. The severe inflammation and necrosis allow translocation of enteric flora that is commonly associated with sepsis. CPV-2 are shed for approximately 3 to 14 days after infection and shedding can begin prior to clinical signs. CPV-2 are environmentally resistant. disease of young dogs called feline panluekopeia virus in cats affects: Gastrointestinal Bone marrow – myelopoiesis Cardiovascular (rarely)

Answer 586

A type of white blood cell that makes antibodies. B cells are part of the immune system and develop from stem cells in the bone marrow. Also called B lymphocyte.

Answer 587

T cell, also called T lymphocyte, type of leukocyte (white blood cell) that is an essential part of the immune system. T cells are one of two primary types of lymphocytes—B cells being the second type—that determine the specificity of immune response to antigens (foreign substances) in the body. helper T cell and the cytotoxic T cell. As the names suggest helper T cells 'help' other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours