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Microbiology > Unit 6 > Flashcards

Unit 6 Flashcards

1
Q

What are sprophytes

AKA saprobes

A

Microbes that feed off dead/decaying tissues (not a true pathogen since the tissue is already dead/damaged)

Decomposers

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2
Q

What are pathogenic heterotrophs

A

Pathogens that feed of living cells/tissues -causes damage in the process of feeding which releases more nutrients

Live in or on the host

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3
Q

True or false

All viruses are intracellular pathogens, and only some bacteria are

A

True

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4
Q

Why do pathogens have a negative relationship with their host

A

Because the host is being damaged while the pathogen is benefiting

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5
Q

Why are the most successful pathogens the ones that cause a limited amount of damage to the host

A

Because if the host dies the pathogen no longer benefits

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6
Q

What is the exception for the commonly most successful pathogens

A

Pathogens that can easily spread to and infect other hosts which kill their host and movebon to another one

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7
Q

What are primary pathogens

A

Disease causing microbes with the means to breach the defences of a host, and can survive past the natural defensive barriers and initial attack by the immune system

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8
Q

What are opprotunistic pathogens

A

Pathogens that can only cause disease to a host with a compromised immune system or if they are in very large numbers

Can also be acquired from the environment or from others

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9
Q

What are some examples of a host with a compromised immune system

A 
Very sick
Malnourished 
Internal parasites 
Immunosuppresive drugs (steroids, chemotherapy)
Poor hygiene 
Pregnant 
Neonates
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10
Q

True or false

There is often opprotunistic pathogens in normal flora

A

True

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11
Q

If the host is immune suppressed, the numbers of microbes cannot be suppressed, so opprotunistic pathogens

A

Can easily overwhelm and start disease

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12
Q

What are the 6 steps of microbial disease

A 
Transmission
Infection(entry-attachment-colonization)
Replication
Tissue damage
Spread within the host 
Spread outside the host
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13
Q

What is transmission

A

The spread of the disease (first step in infectious disease process)

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14
Q

Normal flora that can cause disease does not need to be transmitted (already in host, but all other pathogens

A

Must be acquired through transmission

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15
Q

What is direct transmission

A

From animal to animal, requires physical contact between the infected and susceptible animals

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16
Q

Pathogens that need direct contact ____ when away from the host

A

Readily die in the environment when away from the host, often from drying

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17
Q

What are some examples of direct transmission

A 
Touching
Kissing
Sexual contact
Contact with body lesions 
Contact with bodily fluid (blood, saliva)
Aerosal transmission
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18
Q

What is aerosal transmission what is it considered

A

Respiratory or nasal secretions, droplets, that can travel short distances, usually inhaled or land on mucus membranes

Not always considered direct transmission, some consider it air borne transmission

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19
Q

What is indirect transmission

A

Microbe is aquired from a contaminated surface/environment

These microbes are usually more resistant and can survive in the environment

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20
Q

What are some ways of indirect transmission

A

Fomites
Water borne transmission
Air borne transmission
Vector borne transmission

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21
Q

What are fomites

A

Any inanimate object that conveys a pathogen from one individual to another

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22
Q

What is air borne transmission

A

Pathogens carried in evaporated droplets or dust through the air

Usually land on a fomite

Very small and resistant to drying

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23
Q

What are some examples of air borne diseases

A

Anthrax
Influenza
Foot and mouth disease

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24
Q

What is vector borne transmission

A

Small animals capable of transmitting disease

Ex. Mosquitos (most common, carry westnile), ticks, fleas, flies

Vector itself does not undergo pathology, carries pathogen from infected animal to susceptible animal

Called vector borne diseases

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25
Q

What is fecal oral transmission

A

Organisms in feces accidentally ingested by contamination

Can be direct or indirect (grooming, contaminated food, water and soil)

Most common reason for spread of pathogens from animal feces to people

Salmonella, parvovirus, E. coli

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26
Q

How can fecal-oral transmission be reduced

A 
Cooking food
Hand washing
Protection of water supply
Keeping feed away from feces 
Picking up dog feces
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27
Q

What is vertical transmission

A

Spread of disease from mother to child

3 ways:
In utero: from mothers blood via the placenta to the fetus
Trans-vaginally: exposed in birthing canal (pathogens from urogenital tract and feces) enters via swallowing
Nursing: pathogens in mammary glands and secreted in colostrum/milk and ingested by neonates

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28
Q

What decreases chances of trans vaginal transmission

A

C sections

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29
Q

What is horizontal transmission

A

Pathogens that are spread by routes other than mother to child , includes direct and indirect transmission

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30
Q

What are nosocomial infections

A

Diseases acquired while in the hospital/Clinc

Can be direct or indirect (aerosals, fomites, contaminated fluids (squirt bottles and water baths))

Always a concern

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31
Q

Why are nosocomial infections harder to treat

A

Microbe had a greater chance of having antimicrobial drug resistance (previously exposed to antibiotics and survived while in hospital)

Greater chance of being exposed to an immunocompromised patient, more likely to get infected, and more dependent on drugs

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32
Q

What is zoonosis

A

Disease that are passed from animal to people or vise versa

Direct or indirect ( saliva, blood, urine, feces, bites, ingestion)

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33
Q

According to the centers for disease control (CDC) ___% of human infectious diseases are potential zoonoses

A

60%

34
Q

According to the centers for disease control (CDC) ___% of new emerging diseases are zoonotic

A

75%

35
Q

What are some important zoonoses

A

Rabies
Salmonella, E. coli, campylobacter
Toxoplasma gondii, Giardia
Roundworms

36
Q

What is endemic

A

An infectious disease always present in a population at a low level

Common cold, seasonal flu, radies, distemper

37
Q

What is Epidemic

A

When there is a sudden increase in the numbers of cases in a period of time with a population (stays within a community, rapidly spreading)

38
Q

What is pandemic

A

Widespread epidemic, more cases in a short amount of time and moves to adjacent communities

39
Q

Pandemic and epidemics are usually due to

A

New infectious diseases
New species that has entered a diff host
New strain that the immune system doesnt recognize
New strain with increased pathogenicity

Population lacks prior exposure and does not have immunity to fight it

40
Q

What is infection and the 3 steps of it

A

The second step in infectious disease process

Entry
Attachment
Establishment/colonization

All 3 must occur in order for disease to occur

41
Q

What is entry In the first part of infection

A

Infection depends on the number of pathogens that enter the host

42
Q

What are some protective barriers of the body that prevent entry

A 
Skin 
Tears
Gastrointestinal mucosa
Stomach acid
Normal GI flora
43
Q

What are some examples of distuptions to the protective barriers and what does it cause

A 
Scratches
Wounds
Inflammation of the respiratory/urogenital tracts 
Injections
Disruption of GI flora

Increases the chance of entry and adhesion of pathogens

44
Q

What is the minumum infectious dose

A

The minimum number of microbes that must enter the host in order for disease to occur

45
Q

What does the minumum infectious dose depend on

A

Pathogenicity of the microbe

Immune state of the host

46
Q

What is attachement in the infection process

A

After entry, the microbe must attach to cells and body surfaces before replication can occur

Any bacteria that do not adhere can be washed out (urination, peristalsis, tears)

47
Q

How do bacteria attach

A 
Fimbriae 
Pilli
Lipopolysaccharides 
Slime layers 
Receptors on the surface of bacteria bind to specific receptors on the surface of host cells
48
Q

What is establishment/colonization in the infection process

A

Once the microbe is attached, it can start to multiply

49
Q

If the immune system can attack and eliminate the infection faster than the bacteria can replicate, the animals will___

A

Not become sick

50
Q

In most causes the animal recieves the ____ and the immune system will not be able to clear the infection and itnwill become sick

A

Minimum infectious dose

51
Q

What is pathogenicity

A

Meausre if how much damage a microbe causes

52
Q

What is a pathogen

A

A microbe that causes damage

53
Q

Why are primary pathogens the most virulent

A

Minimum infectious dose: 3-100,000
Disease produced: distinct
Source of infection: transmitted
Host state: can be healthy

54
Q

Why are opprotunistic kind of virulent

A

Minumum infectious dose: 100,00+
Disease produced: non specific
Source if infection: normal flora
Host state: mild-moderate immune suppression

55
Q

Why are non pathogens the least virulent

A

Minimum infectious dose: 1,000,000+
Disease produced: non specific
Source of infection: normal flora
Host state: severe immune suppression

56
Q

What is direct damage

A

Damage due to the action of the microbe

57
Q

Bacteria and fungi produce toxins that damage surrounding tissues to

A

Release nutrients

Enable spread to other tissues

58
Q

What are some examples of toxins that cause damage and what do they do

A

Hemolysin: breakdown RBCs
Collagenase: breaks down connective tissue
Enterotoxins: damage GI barrier so nutrients arent absorbed

59
Q

Viruses use host cells as “factories for multiplication” and often kill the cell in order to

A

Release newly formed viruses

60
Q

What is indirect damage

A

From when the immune sustem reacts to the presence of an infectious organisms

Causes Inflammation which damages tissues in the process of destroying bacteria

61
Q

What si the course of a disease/the clinical pattern

A

1: infection (entry, attachment, start to multiply)
2: incubation
3: prodromal period
4: clinical/symptomatic period
5: resolution
6: convalesence

62
Q

What is exposure

A

When aniamls come into contact with potential pathogens

Dose not always mean there will be disease (must enter attach and establish)

It isnpossible for the immune system to clear the microbe before it can attach

63
Q

The ability to cause disease depends on

A

Infectious dose

Pathogenicity of microbe

Immune status of the animal

64
Q

What is the incubation oeriod

A

Time between exposure to the pathogen and when clinical signs first appear

There are not clinical signs or symptoms in this time

Pathogen is establishing itself and multiplying (damage is minimal)

Microbes can be shed during this time

65
Q

True or false

The incubation period is the same for all microbes

A

FALSE
it is specific to the microbe

Parvovirus: 4-7 days
Rabies: up to 6 months

66
Q

What is the prodromal period

A

Following incubation when there are non-specific clinical signs

Ex. Lethargy, fever, decreased appetite

Animal is sick but signs do not indicate a specific disease or where it may be occuring

Pathigen is established but numbers are still low

67
Q

What is the clinical period

AKA symptomatic period

A

Period with the highest number of infectious organism

Clinical signs are specific to colonization of a specific tissue and/or specific pathogenic factor specific to that organism

Easiest stage to diagnose

68
Q

What are some specific signs of radies and bordetella

A

Rabies: neurological symptoms
Bordetella: rhinotracheitis

69
Q

What is the resolution period

A

Decreasing numbers of pathogen with a corresponding decrease in secerity if clinical signs

By activation of the immune system or treatment

70
Q

What is convalescence period

A

When specific symptoms are GONE

Infectious organisms are still Present in very low numbers (not enough to cause disease)

Body is returning to normal

Can still shed the pathogens

71
Q

During the convalescence period there is an increased

A

Risk of re-infection

Risk of getting other diseases

72
Q

What is shedding

A

Transmitting disease or pathogen to others

73
Q

What is reinfection

A

Previous infection was resolved but same infection has started again from the transmission stage

Usually a sign of an underlying issue (hygiene, immune system, stress)

74
Q

What is a reccurent disease

A

Reinfection at weekly to monthly intervals

75
Q

What is a resistant disease

A

The original infection was never completely resolved, so it is still present due to failure to treat it

76
Q

What are chronic symptomatic infections

A

Infection persists with continued symtoms, occurs if the host immune response is unable to clear the infection

77
Q

What is a chronic asymptomatic infection

A

Infection persists at low levels, low levels of replication, no clinical signs,

May or may not be able to shed disease

78
Q

What is a latent infection

A

A form if chrinic asymptomatic infection when the organism remains in the host but is not actively replication or producing pathogenic factors (no clinical signs)

No risk of tansmission

79
Q

What happens in a latent infection if the infectious organism is reactivated

A

Start to replicate again and produce pathogenic factors, and will return to clinical stage and transmit to others

80
Q

What is remission

A

When clinical signs are temporarily absent

Can stay in remission for long or short periods of time

Means the infection was never cured

81
Q

What us relapse

A

Periods when clinical signs are present

When infectious organism starts to replicate again and produce pathogenic factors

82
Q

What happens when an infection causes death

A

When the severity of clinical signs go above the clinical threshold

Microbiology (12 decks)

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