L17: Population medicine and epidemiology in VPH Flashcards
(26 cards)
What is a cross-sectional survey?
Events at a particular point in time
What is a longitudinal survey?
Events over a period of time
What are the two types of longitudinal survey?
Prospective or retrospective
What is the difference between monitoring and surveillance?
Monitoring = routine observations, surveillance = more intensive data recording
Why are endemic levels predictable?
Endemic implies a stable state
What is a hyperendemic?
Continuously present to a high level affecting all ages equally
What is an epidemic?
Levels in excess of expected
What must have happened for an epidemic to arise?
Must have been subjected to factors that weren’t there previously
What are Evans’ postulates?
The association between a causal factor and the disease must be statistically significant - but this doesn’t prove causation
What are the two types of association?
Non-statistical (chance) or statistical
What are the two types of risk indicators?
Causal or non-causal
What are “causal risk indicators” called?
Risk factors
What is incidence?
The number of new cases over a period of time in relation to the population at risk
What two factors does prevalence depend on?
Duration and incidence (prevalence = incidence x duration)
What is a determinant of disease?
Any characteristic affecting the health of a population
What are two examples of an “agent determinant”?
Virulence, pathogenicity
What are three examples of environmental determinants?
Location, climate, husbandry
In which kind of infections can determinants interact?
Mixed
What is “generation time”?
Time between infection and max shedding
What is effective contact time like in seasonal disease?
Short
Which two ways can vertical transmission occur?
Inherited (hereditary) and acquired (congenital)
What are four mechanisms of congenital transmission?
Germinative, transplacental, ascending infection, infection and parturition
What is R0?
Number of new infections from a single infected individual in a fully susceptible population
What happens is R>1?
Exponential growth
