Epidemiology of Infectious Diseases Flashcards
what is the goal of epidemiology
Identifying the causes of disease and the mechanisms by which they spread
-in order to come up w acceptable public health interventions
what is epidemiology purposes in public health practice
- discover the pathogen, host and environmental factors
- Identify those segments @ greatest risk
- Evaluate effectiveness of health programs
What is the attack rate of a disease
of people at risk who develop disease/ # of people at risk during a time period
Sporadic Infections
Occasional, from time to time ifrequently and irregulary
Endemic infections
Constant presenceof a disease or infectious agent within a given geographic area
-random, unpreditable, isolated cases
what is an epidemic or outbreak
disease occurrence among a population that is in excess of what is expected in a given time and place (sudden higher than normal incidence)
what are the 2 types of epidemics
Common source- explosive outbreak (like food poisoning)
Propagate- progressive person to person spread
what is the primary case vs the index case
primary- person who brings the infection to a population
Index- the first disease case brought to the attention of the epidemiologist
What is the basic reproductive rate (R0)
average # of secondary cases of infection arising from primary case IN FULLY SUSCEPTIBLE POP
What determines R0 (3 things)
p= transmission probability per exposure
c= number of contacts per unit time
d= duration of infectious period
What is the effective reproduction rate (R)
avg # of secondry infection arising from primary case in a pop with variable/ partial susceptibility
What is the one determinate the makes R different from R0
the proportion of the pop that is already immune
What is herd immunity
The indirect protection from infection of susseptible members due to the prescense of immune indvs
