1- Applied epidemiology Flashcards
Define Epidemic
The occurrence in a community or region of cases of an illness, specific health-related behaviour, or other health related events clearly in excess of normal expectancy
Define endemic
The constant occurrence of a disease, disorder or noxious infectious agent in a geographic area or population group, it may also refer to the chronic high prevalence of a disease in such area or group
Define contagious disease
A disease transmitted by direct or indirect contact with a host that is the source of the pathogenic agent. The same disease can be contagious in some species and not in others
Define communicable disease
A disease whose casual agent can be transmitted from successive hosts to healthy subjects, from one individual to another
Define morbidity
Any departure, subjective or objective, from aa state of physiological or psychological well-being.
Define mortality
the state of being subject to death
Define positive predictive value
The probability that a person with a positive test result is a true positive
Define negative predictive value
The probability that a person with a negative test result is a true negative
Define prevention
Actions that prevent disease occurrence
Define eradication
termination of all transmission of infection by extermination of the infectious agent through surveillance and containment
What is the R number
Basic reproduction
The average number of cases infected by a primary case when the population is naive
What is the R number of endemic diseases?
Endemic disease = Disease found in/restricted to a particular region
R0 <1 (Average number of cases inf. is less than one)
Questions to ask when approaching a disease investigation?
How many cases?
Are all animals/people at risk?
In what areas?
Over what time?
Are there specific subgroups that are more likely to be infected?
Epidemic curve:
What structure does the curve have if a common exposure is identified? (Food poisoning)
Rapid increase in cases > Then tight clustering of cases
What are case-control studies?
Compare between cases and non-cases (Diseased and non-diseased)
Look retrospectively at the differences in exposure to risk factors
What are cohort studies?
Looks at individuals exposed and not exposed to risk factors and see if they develop the disease
What is an odds ratio?
Odds of the disease in the exposed group vs with odds of the disease in the unexposed group.
common in disease control studies
What is a relative risk ratio?
Comparison between the risk of an outcome in the exposed group vs in the unexposed group
Describe the ‘test and remove’ strategy of disease eradication
Animals testing positive are removed and slaughtered
Describe the ‘pre-emptive’ strategy of disease eradication
○ Animals that have been exposed to infection are slaughtered
Describe the ‘blanket culling’ strategy of disease erdaication
Animals on contiguous premises surrounding an infected farm are culled
Describe the ‘stamping out’ strategy of disease eradication
Combination of:
Test and removal
Pre-emptive
Blanket culling
as well as other preventative measures
What is the R number in epidemic disease
R0 > 1
The average number of cases infected by a primary case is greater than 1
If OR>1 what does this suggest
Risk factor not associated with disease
