Disease Control Flashcards

1
Q

Three things are necessary to be able to

potentially eradicate an infectious disease

A

– Effective intervention is available to interrupt
transmission of the agent
– Practical diagnostic tools with sufficient
sensitivity and specificity are available to
detect levels of infection that lead to
transmission
– There are no other vertebrate reservoirs and
the disease does not amplify in the
environment

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2
Q

A disease eradication initiative is largely

dependent on

A

the level of societal and

political commitment

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3
Q

Two components of RISK

A

(1) Probability of Harm
(2) Severity of Impact of a
Hazard

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4
Q

8 Factors affecting Risk

Perception

A
  • Catastrophic potential
  • Familiarity
  • Understanding
  • Scientific certainty
  • Controllability
  • Is exposure voluntary?
  • Impact on children
  • Dread results
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5
Q

In broad terms what is Disease Control

A

Reduction of morbidity and mortality

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6
Q

What is Biosecurity

A

Any practice or system that prevents the spread
of infectious agents from infected animals to susceptible animals.

Any practice that prevents the introduction of
infected animals into a herd, region or country
in which the infection has not occurred.

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7
Q

Factors affecting Control

A
  • Mode of transmission
  • Host specificity
  • Ease of spread
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8
Q

6 Important Factors in Veterinary

Disease Control Programs

A
• Knowledge of the cause, maintenance and
transmission of the disease
• Veterinary infrastructure
• Diagnostic feasibility
• Availability of replacement stock
• Producer’s opinions and cooperation
• Public opinion
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9
Q

4 Important Factors in Disease

Control Programs

A
• Public health considerations
• Requirement for legislation and
compensation
• Ecological consequences
• Financial support
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10
Q

Pathognomonic tests

A
  • Absolute predictor of disease or disease agent

* Can have false negatives

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11
Q

Surrogate Tests

A
  • Detect secondary changes that will hopefully predict the presence or absence of disease or the disease agent
  • Can have false negatives and false positives
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12
Q

True Prevalence =

A

True Prevalence = (A+C)/N

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13
Q

Apparent Prevalence =

A

Apparent Prevalence = (A+B)/N

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14
Q

Sensitivity =

A

Sensitivity = A/(A+C)

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15
Q

SnNout

A

If highly sensitive test has a negative result you can rule out false negative

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16
Q

Specificity =

A

Specificity = D/(B+D)

17
Q

SpPin

A

Positive result with specificity test you can rule in.

18
Q

What does sensitivity test for?

A

Proportion of diseased animals that test
positive

Ability of diagnostic test to detect disease

19
Q

What does specificity test for?

A

Proportion of non-diseased animals that
test negative

Ability of diagnostic test to detect nondiseased
animals

20
Q

What type of test do you want to run if you are trying to rule out a disease?

A

Use a test with high sensitivity and a high
negative predictive value.

SnNout

21
Q

What type of test do you run if you are trying to rule in a disease or
confirm a diagnosis?

A

Use a test with high specificity and a high
PPV.

SpPin

22
Q

What is the cost of a false positive test?

A

– High treatment costs
– Treatments that are potentially dangerous
– Euthanasia of valuable animal might be
possible
– Use highly specific tests
– Multiple tests should be interpreted in series

23
Q

Strategies for Directed Action
against Disease at the
Population Level

A
  1. Selective Slaughter
  2. Depopulation
  3. Quarantine
  4. Reduction of Contact
  5. Mass treatment
  6. Mass Immunization
  7. Education
  8. Environmental Control
  9. Applied Ecology
  10. Genetic Improvement
24
Q

Selective Slaughter

A

Test and slaughter

Slowly Spreading disease

More expensive as disease becomes rarer

Example = Brucilosis

25
Depopulation
Whole pop including non-infected Rapidly Spreading disease Example = Foot and Mouth
26
Quarantine
Physical separation of sick animals from healthy Difficult with large size areas like wood bison national park
27
Reduction of Contact
Separate physically Separate in time - dont milk staph cows b4 clean cows Example = Staph mastitis
28
Mass Treatment
Treat all animals (sick and well) Diseases occurring at very high prevalence Example: Deworming Problems: Disease resistance
29
2 problems with mass immunization?
1. Panacea - ppl thin that if vaccinated that they dont have to worry about other preventative measures 2. Can interfere with screening (cant tell vaccinated from infected)
30
Example of Education
Somatic cell count penalty programs