The constant presence of a disease or infectious agent within a given geographical area or population group
ex. TB in the US
The occurrence in a community or region of cases of an illness with a FREQUENCY clearly in excess of normal expectancy
(Usually an annual comparison of this year to last year)
An epidemic occurring over a very wide area, crossing international boundries and affecting a large number of people
ex. HIV, Plague Spanish Flu or 1918
The immunity of a group or community. The resistance of a group to invasion and spread o an infectious agent based on the reistance to infection of a high proportion of individuals.
What % of the population needs to be vaccinated for Measles in order to get herd immunity?
Does an association between 2 variables imply a cause and effect relationship?
ex. Every child that has leukemia in the US ate a hotdog before they go leukemia. It is an association, but doesn't show there is a cause and effect relationship
Which is the strongest of all the criteria that help to establish a cause and effect releationship?
Temporality--Being able to have a clear timeline that shows exposure followed by disease
Who was one of the first people to look at epidemiology? He investigated cholera outbreaks in London and tracked the causative agent to a water pump.
Who is John Snow?
He is one of the first epidemiologists
He is famous for investigating a cholera outbreak in London down to a water pump
Who is Ignaz Semmelweis?
He is an early epidemiologist who noticed that women being treated by students & physicians, that were also performing autopsies were dying more than women treated by midwives.