final exam past qs

Question 1

label if either adaptive or innate

a) requires activation to produce efficient response

b) receptors recognize specific molecules (antigens)

c) responds w the same intensity & speed each time it encounters a particular pathogen

d) is not present in lower level animals such as invertebrates

Answer 1

a) adaptive
b) adaptive
c) innate
d) adaptive

Question 2

cytotoxic T cells are major defence against which of the following class of organisms

viruses
fungi
extracellular bacteria
protozoans

Answer 2

viruses

Question 3

A dog is responding to a respiratory microbial infection and develops enlarged lymph nodes. Which of the following events is NOT occurring in the lymphoid follicles in these lymph nodes?

Affinity maturation of Ig variable genes

Immunoglobulin gene (VDJ) rearrangement

Follicular helper T cell

interactions with B cells
B cell proliferation

Answer 3

Immunoglobulin gene (VDJ) rearrangement

Question 4

Which of the following statements about high affinity antibodies is FALSE?

They bind tightly to epitopes on pathogens.

There is a high level of complementarity between their amino acid sequence and that of the pathogen epitope.

They result in more rapid elimination of pathogens.

They are produced by isotype switching of B cells.

Answer 4

They are produced by isotype switching of B cells.

Question 5

Phagocytosis is an important component of the innate immune response.
(a) What are the TWO (2) main cell types that undertake phagocytosis?

Answer 5

Macrophages and neutrophils

Question 6

Which of the following is a feature of Natural Killer cells?

They express clonally distributed antigen receptors that directly bind antigen in the surface of microbes.

They require helper T cells for activation.

They kill virus-infected cells by initiating apoptosis via the Fas-Fas ligand pathway.

They are activated by recognising microbial peptides bound to host class I MHC molecules.

Answer 6

They kill virus-infected cells by initiating apoptosis via the Fas-Fas ligand pathway.

Question 7

Which of the following statements about the Career Choice step in B cell maturation is TRUE?

Most cells become memory B cells.

Cells that become plasma cells continue to circulate in the plasma (blood).

B cells that become memory B cells respond readily to low levels of antigen.

The B cell receptor (BCR) on memory B cells is generally of low affinity.

Answer 7

B cells that become memory B cells respond readily to low levels of antigen.

Question 8

Which of the following statements about the pattern recognition receptors of the innate immune system, such as Toll-like receptors, is TRUE?

They are encoded by genes produced by recombination of gene segments that are separated in inherited germline DNA.

They undergo somatic mutation and affinity maturation in response to microbial antigens.

They recognise pathogen associated molecular patterns such as viral nucleic acids and bacterial cell wall constituents.

Each clone of macrophages express a unique set of these receptors that differs in specificity from the receptors on all other clones of macrophages.

Answer 8

They recognise pathogen associated molecular patterns such as viral nucleic acids and bacterial cell wall constituents.

Question 9

A pup received a full course of vaccinations against canine distemper virus. At 4 years of age, it was boarded in a kennel where an outbreak of distemper occurred. Despite the exposure, it did not become infected with distemper virus. Which of the following properties of the adaptive immune system is best illustrated by this scenario?

Memory
Diversity
Self-tolerance
Specificity

Answer 9

Memory

Question 11

The image above shows a resting mast cell with antibody molecules bound to the surface via the Fc receptor. The isotype (class) of antibody is [IgM IgE IgG IgA]. The main role of this antibody isotype in the immune response is in [parasite infections.blood-borne infections.bacterial infections.mucosal infections].. Binding of cognate antigen to the antibody molecules results in [clustering of B cell receptors on the mast cell.induction of apoptosis in the mast cell.expression of MHC I molecules on the surface of the mast cell.release of granules from the mast cell]. and the recruitment of [macrophages eosinophils cytotoxic T cells dendritic cells] to the site.

Answer 11

IgE
parasite
release of granules from the mast cell
eosinophils

Question 12

A healthy 2-year-old horse is infected with an upper respiratory tract virus for the first time. During the first few hours after infection, which one of the following events occurs?

The innate immune system responds rapidly to the viral infection and keeps the virus infection under control.

B and T lymphocytes recognise the virus and stimulate the innate immune response.

Passive immunity mediated by maternal antibodies limits the spread of infection.

The adaptive immune system responds rapidly to the virus and keeps the viral infection under control.

Answer 12

The innate immune system responds rapidly to the viral infection and keeps the virus infection under control.

Question 13

Which of the following properties of antibodies is NOT related to the isotype (class) of the antibody?

Amino acid sequence of the constant region of the heavy chain

Ability to be transported into the lumen of mucosal surfaces

Antigen specificity

Ability to activate basophils

Answer 13

Antigen specificity

Question 14

The diagram above shows the activation of a helper T cell. The structure labelled A is [MCH II /CD8 /T cell receptor /CD4]. The structure labelled B is [MHC II/CD8/MHC I/CD4]. The cell labelled C is most likely to be a [macrophage/cytotoxic T cell/ mast cell/ neutrophil. The label D indicates an antigenic peptide. This peptide is[ anchored at the ends of the peptide binding groove/was linked to ubiquitin and broken down in a proteasome/is 12-24 amino acids in length/was derived from an endogenous antigen]

Answer 14

T cell receptor
MHC 2
macrophage
is 12-24 aa in length

Question 15

Complement proteins are involved in which of the following processes?

Apoptosis
Opsonisation
Signal transduction
Antibody-dependent cell-mediated cytotoxicity (ADCC)

Answer 15

Opsonisation

Question 16

Which of the following is NOT a characteristic of the innate immune system?

Requires activation of cells for an effective response.

Responds with the same speed and intensity each time it meets a pathogen

Antigen recognition receptors are encoded in the germline.

Components of the system are present in invertebrates.

Answer 16

Requires activation of cells for an effective response.

Question 17

Which of the following statements does NOT apply to this immunoglubulin isotype?

Neutralises viruses
Opsonises bacteria
Can activate complement
Moves readily into tissues

Answer 17

Moves readily into tissues

Question 18

Which of the following statements about high affinity antibodies is INCORRECT?

They are produced by isotype switching of B cells.

There is a high level of complementarity between their amino acid sequence and that of the pathogen epitope.

They result in more rapid elimination of pathogens.

They bind tightly to epitopes on pathogens.

Answer 18

They are produced by isotype switching of B cells.

Question 19

The receptor that is responsible for the transport of IgA across the epithelial barrier is:

Poly Ig receptor
Poly Fc receptor
Poly C3b receptor
Poly Fab receptor

Answer 19

Poly Ig receptor

Question 20

Natural killer (NK) cells recognise and kill:

Intracellular pathogens.

Normal host cells.

Cells with decreased expression of MHC-I molecules.

Cells with increased expression of MHC-I molecules.

Answer 20

Cells with decreased expression of MHC-I molecules.

Question 21

List the FOUR (4) main stages in phagocytosis.

Answer 21

Chemotaxis:
Opsonization & adherence
Ingestion
DESTRUCTION:

Question 22

After production in the bone marrow, T cells undergo a series of “exams” in the thymus before they return to circulation.
Which of the following statements is TRUE regarding these “exams”?

Negative selection occurs in the cortex of the thymus.

Positive selection occurs in the medulla of the thymus.

Negative selection removes cells that fail to recognise self MHC molecules.

Negative selection removes cells that have high affinities for self-antigens.

Answer 22

Negative selection removes cells that have high affinities for self-antigens.

Question 23

Select the most correct statement about memory T-cells:

Produce antibodies against pathogens.
Have a short half-life.
Are an important part of the innate immune response.
Bind efficiently to antigen-presenting cells.

Answer 23

Bind efficiently to antigen-presenting cells.

Question 24

Which MHC I allele(s) appear to be associated with increased risk of developing disease in BLV-infected animals?

Alleles 2 and 4
Alleles 1 and 3
Allele 2
Allele 1

Answer 24

Alleles 1 and 3

Question 25

Which of the following methods of disinfection would be most effective and practical for use to sterilise surgical drapes? Dry heat oven A phenolic chemical disinfectant A bisguanide cationic chemical disinfectant Autoclaving

Answer 25

Autoclaving

Question 26

Which of the following statements BEST defines a 5D treatment for environmental decontamination? Select one alternative: The process inhibits the growth of bacteria to less than five decimal logarithms. The process reduces contamination with dirt, dust, dermatophytes, dried faeces, and detritus. The process inhibits the growth of bacteria to less than five doubling count increases. The process reduces the bacterial count by five decimal logarithms.

Answer 26

The process reduces the bacterial count by five decimal logarithms.

Question 27

Which of the following is NOT a disadvantage of the use of chlorine based disinfectants? Potential user health issues Narrow spectrum of action against microbes Needs to be made up as fresh working solutions each day Readily inactivated by organic matter

Answer 27

Narrow spectrum of action against microbes

Question 28

The term facultative anaerobe refers to an organism that: is killed by oxygen does not use oxygen but tolerates it uses oxygen when present or grows without oxygen when oxygen is absent prefers to grow without oxygen

Answer 28

uses oxygen when present or grows without oxygen when oxygen is absent

Question 29

The firmicutes group of bacteria is mainly made up of: Enteric bacteria such as E. coli Bacteria that lack a cell wall, such as Mycoplasma Gram positive bacteria, including the spore-forming anaerobes Spiral-shaped bacteria, such as Leptospira

Answer 29

Gram positive bacteria, including the spore-forming anaerobes

Question 30

Which of the following is the best definition of bacterial generation time? The time it takes for a reproducing bacteria to double in size The time lag before bacteria commence growing at an exponential rate The time it takes for a bacterial population to double in size numerically The time required for significant genetic change to occur in a bacterial populatio

Answer 30

The time it takes for a bacterial population to double in size numerically

Question 31

Some bacteria have complex nutritional requirements because they: have many different enzymes and therefore can make many molecules are composed of a large number of different types of molecules lack many enzymes and must therefore be provided with many of the molecules they need for growth can make a great many of the molecules found in the cell from simple precursors

Answer 31

lack many enzymes and must therefore be provided with many of the molecules they need for growth

Question 32

During which phase of bacterial growth would penicillin, an antibiotic that inhibits cell-wall synthesis, be most effective? log phase death phase stationary phase lag phase

Answer 32

log phase

Question 33

Which of the following statements about agent determinants is TRUE? Pathogenicity is based on the proportion of infected animals that develop severe disease (or death). Virulence is based on the proportion of exposed animals that develop signs of clinical disease. Virulence is based on the proportion of exposed animals that develop infection. Pathogenicity is based on the proportion of exposed animals that develop signs of clinical disease.

Answer 33

Pathogenicity is based on the proportion of exposed animals that develop signs of clinical disease.

Question 34

Which of the following statements about infectious versus contagious diseases is FALSE? All infectious diseases are also contagious. All contagious diseases are also infectious diseases. Infectious diseases and contagious diseases are caused by infectious agents. Not every infectious disease is contagious.

Answer 34

All infectious diseases are also contagious.

Question 35

Hendra virus (HeV) is maintained in bat populations and occasionally spills over to infect horses. HeV infection can cause severe and often fatal disease in horses and in people. HeV infected horses shed a lot of virus and can infect people. Horses infected with HeV have a latent period shorter than the incubation period. Vaccination of horses against HeV can greatly reduce the risk of horses being infected with HeV and shedding virus if infected. Select one or more alternatives: Horses in the incubation stage of HeV infection may be shedding infectious virus even though they are showing no apparent clinical signs of illness. Horses will only be shedding HeV if they are showing clinical signs of Hendra virus infection. Veterinary personnel should consider putting biosecurity measures in place even when working on healthy horses to minimise risk of exposure to HeV. Horse owners should vaccinate horses against HeV as part of reducing Hendra disease risk in horses and in people.

Answer 35

Horses in the incubation stage of HeV infection may be shedding infectious virus even though they are showing no apparent clinical signs of illness. Veterinary personnel should consider putting biosecurity measures in place even when working on healthy horses to minimise risk of exposure to HeV. Horse owners should vaccinate horses against HeV as part of reducing Hendra disease risk in horses and in people.

Question 36

Which of the following statements about droplet transmission is FALSE? Droplet transmission is a form of direct contact transmission. Droplets are relatively large and heavy and fall to the ground quickly and generally travel <2 metres. Droplets are very small floating particles that can remain suspended in air for a long time and transmit infection over long distances. Droplets may contaminate nearby surfaces or material (feed) and transmission may then occur if a susceptible host ingests or licks the contaminated surface.

Answer 36

Droplets are very small floating particles that can remain suspended in air for a long time and transmit infection over long distances.

Question 37

Which of the following statements about latent and incubation periods is FALSE? The latent period can have a different duration to the incubation period in different infectious diseases. The latent period is always the same duration as the incubation period for a specific disease. The incubation period is the time from exposure to onset of clinical signs. The latent period is the time from exposure to onset of shedding of infectious agent.

Answer 37

The latent period is always the same duration as the incubation period for a specific disease.

Question 38

Which of the following statements about standard infection control precautions are TRUE? Note: You will receive part marks for each correct response. Select one or more alternatives. Standard precautions should be applied ALL THE TIME. Standard precautions should only be applied when there is a high level of suspicion of a specific disease or infection spread risk. Apply common sense practices and simple personal protective equipment (PPE) to protect veterinary workers and prevent spread of infection from animal to animal. Standard precautions are based on the assumption that all people and animals are capable of being a source of infectious agents at all times.

Answer 38

Standard precautions should be applied ALL THE TIME. Apply common sense practices and simple personal protective equipment (PPE) to protect veterinary workers and prevent spread of infection from animal to animal. Standard precautions are based on the assumption that all people and animals are capable of being a source of infectious agents at all times.

Question 39

Which of the following statements about control of Streptococcus uberis is TRUE? It is possible to eliminate this bacteria from dairy herds through a combination of effective treatment of infected cows and testing milk of purchased cows and only bringing cows into the herd if their milk tests negative. Culling cows with persistent infection is a very important measure to help eliminate the disease from a herd. Best practice milking hygiene and milking machine maintenance are not important to prevent spread from cow to cow in the milking shed. It is not possible to eliminate the bacteria from the environment and management should focus on a combination of farm hygiene to reduce environmental exposure, milking shed hygiene and treatment of cows with mastitis.

Answer 39

It is not possible to eliminate the bacteria from the environment and management should focus on a combination of farm hygiene to reduce environmental exposure, milking shed hygiene and treatment of cows with mastitis.

Question 40

In 2024, Biosecurity Queensland conducted a serosurvey for Lumpy Skin Disease across properties in Northern Australia. The epidemiologists adjusted the results for the total population at risk in each property. The measure of disease frequency that can be estimated using the data collected is: Incidence risk Incidence rate Prevalence Incidence

Answer 40

Prevalence

Question 41

During an epidemiological investigation you estimated an Odds Ratio of 1.2. This measurement means: Odds of exposure in the non-diseased group is higher than odds of exposure in the diseased group. Odds of disease in the exposed group is higher than odds of disease in the non-exposed group. Odds of exposure in the diseased group is higher than odds of exposure in the non-diseased group. Odds of disease in the non-exposed group is higher than odds of disease in the exposed group.

Answer 41

Odds of exposure in the diseased group is higher than odds of exposure in the non-diseased group.

Question 42

Following the introduction of a new animal from a goat dairy herd with history of Coxiellosis, two animals showed symptoms concordant with Coxiella burnetii infection 3 months post-introduction, including abortions. This information would allow defining: A symptomatic case definition A probable case definition A confirmed case definition A suspect case definition

Answer 42

A probable case definition

Question 43

Surveillance for tick fever is characterised by evaluating the presence of Babesia bovis in capillary blood smears from cattle in properties located along the tick line. This surveillance system is best described as: An active, targeted surveillance system A risk-based, active surveillance system A risk-based, syndromic surveillance system A passive, case-based surveillance system

Answer 43

A risk-based, active surveillance system

Question 44

The relationship between the basic reproductive number of infection (R0) and the average duration of infectiousness can best be described by: R0 is higher for a disease with a longer average duration of infectiousness. R0 is only influenced by the average duration of infectiousness in vaccinated individuals. R0 is not influenced by the average duration of infection. R0 is lower for a disease with a longer average duration of infectiousness.

Answer 44

R0 is higher for a disease with a longer average duration of infectiousness.

Question 45

In molecular disease surveillance, a strategy that can drastically increase resolution for pathogen detection is: Targeting shorter DNA fragments and using gel electrophoresis of samples. Targeting longer DNA fragments and sequencing positive samples. Increasing the number of PCR cycles to generate larger quantities of pathogen DNA. Using molecular identification fragments that evolve very slowly over time.

Answer 45

Increasing the number of PCR cycles to generate larger quantities of pathogen DNA.

Question 46

Biosecurity Queensland conducted a serosurvey for Lumpy Skin Disease across properties in Northern Australia. The measure of disease frequency that can be estimated using the data collected is: Odds ratio Reproductive number of infection Prevalence Incidence

Answer 46

Prevalence

Question 47

The measure of disease frequency that allows comparison between open populations is: Incidence rate Prevalence Incidence Incidence risk

Answer 47

Incidence rate

Question 48

An estimate of the 2X2 epidemiological table is the attack rate in the diseased group. This measurement is useful to: Calculate the reproductive number of infection Calculate prevalence of infection Calculate the relative risk of disease Calculate the odds ratio of exposure

Answer 48

Calculate the relative risk of disease

Question 49

Following the introduction of a new animal into a cattle herd, symptoms concordant with Foot and Mouth Disease appeared in two animals in the herd after 15 days post-introduction. This information would allow defining: A probable case definition A symptomatic case definition A suspect case definition A confirmed case definition

Answer 49

A probable case definition

Question 50

A propagated epidemic is characterised by: Multiple peaks and troughs in the number of cases within a long-time scale (e.g. weeks or months) A single peak and trough in the number of cases within a short time-scale (e.g. hours to days) A single peak and trough in the number of cases within a long-time scale (e.g. weeks or months) None of the above

Answer 50

Multiple peaks and troughs in the number of cases within a long-time scale (e.g. weeks or months)

Question 51

Abattoir surveillance for Salmonella in beef cattle is characterised by random testing of carcasses along the slaughter line. This surveillance system is best described as: A passive, case-based surveillance system An active, targeted surveillance system A risk-based, syndromic surveillance system A risk-based, passive surveillance system

Answer 51

An active, targeted surveillance system