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9 Cards in this Set
- Front
- Back
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What is R0? How is it determined?
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Tells you how many cases will be caused by each existing case
R0= # of individuals in contact with x probability of transmission x duration of infectivity |
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With an R0 of 10, how many new cases will you have in three incubation periods? What kind of outbreak occur with an R0 of 2?
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1,000
A slowly progressive outbreak that will eventually affect almost every animal |
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What does the R0 need to be for the disease to be considered controlled? Why?
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R0 < 1,
With less than one new case made per infective one, it will eventually die out |
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How do you decrease the R0? Examples?
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Decrease any of the factors in the formula
Quarantine, ring vax, culling |
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How do you figure out what percentage of the herd needs to stop dz transmission? What do you want your number to be?
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Multiply the R0 by the percent of non-immune animals
Less than 1 |
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Canine parvo has an R0 of 8. What is the minimum level of herd immunity you need?
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90% (8 x 0.01 = 0.8)
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What is the Reed-Frost epidemic prediction?
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The probability of transmission from a population of infected cases to a population of susceptible animals
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What are the three variables that the Reed-Frost prediction depends upon?
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1) Probability of effective contact between groups
2) Number of infected 3) Number of susceptible |
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Does the R-F model take into account effects of immunity? What is the most limiting factor of the model? Where wouldn't this work?
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Yes
Must be a closed population like a feed lot Animal shelter |
