Glossary of epidemiology
Last Updated February 23, 2007
The field of epidemiology studies the occurrence, spread and control of infectious disease in populations. Here are some of the terms used:
Antigen: a foreign substance, usually a bacteria or virus, that stimulates the immune system.
Community spread: random cases that can't be traced back to the first infected person.
Endemic: a disease that is constantly present, usually in low numbers in a population.
Epidemic: a disease that occurs in an unusually high number of individuals in a community at the same time. The U.S. Centers for Disease Control says that to epidemiologists "epidemic" and "outbreak" basically mean the same thing, and "outbreak" is often used to avoid sensationalism. SARS was considered an epidemic in Canada.
Incidence: the number of diseased individuals in a population at risk.
Isolation: is used for unusually infectious diseases in hospitals or health care facilities.
Pandemic: a very widespread, often global, disease.
Prevalence: the proportion of diseased individuals in a population at any one time.
Quarantine: limiting the freedom of movement of individuals with active infections to prevent a disease from spreading to other people in the population. The length of a quarantine is the longest period of communicability of a disease. The term is based on the Latin word for 40. During the Great Plague, people were secluded for 40 days.
Strain: a group of organisms within a species that differ in trivial ways from similar groups, as in a new strain of flu virus.
- National Archives of Canada guide to the 1918 flu
- The flu in Elkpoint, Alberta
- Public Health Agency: FluWatch weekly reports
- Health Canada: avian influenza
- World Health Organization: influenza
- U.S. Centers for Disease Control: influenza
- Lung Association: influenza
- Canadian Coalition for Influenza Vaccination
(Note: CBC does not endorse and is not responsible for the content of external sites - links will open in new window)