Lesson 1 Glossary: Epidemiology

Case

An animal or human in a population or study group that has a particular disease, health disorder, or condition under investigation.

Case definition

A set of uniform criteria used to define a case or instance of disease for public health surveillance

Cause

A factor that directly influences the occurrence of disease

Disease

Illness or loss of health

Reportable disease

A disease that is relayed to the relevant health departments when an animal or person is diagnosed with a particular disease

Enzootic/endemic

The constant presence of a disease or infectious agent within a given geographic area or population group

Epizootic/epidemic

The occurrence of more cases of disease than expected in given area or among a specific group over a particular period of time

Epidemiology

The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems

Herd immunity

The indirect protection from an infectious disease that happens when a population (animal or human), is immune either through vaccination or immunity developed through previous infection

Host

An animal or person that can be infected by an infectious agent

Incubation period

The time interval between when an animal or a person is exposed to an infectious agent and when they begin to develop symptoms

Epidemiological studies

Observational studies, in which one observes the course of a disease and clinical trials, which are used to evaluate preventive or therapeutic interventions

Pandemic/panzootic

An epidemic occurs over a very wide area (several countries) and usually affects a large proportion of the population.

Reservoir

The habitat in which an infectious agent normally lives, grows, and multiplies

Sample

A selected subset of a population

Screening test

Tests are conducted for the purpose of identifying a disease in an animal or a person who does not currently have signs or symptoms of the disease

Surveillance

The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community

Transmission of infection

The process by which an infectious agent is spread to a susceptible host

Vector

A living organism that carries an agent from a reservoir to a susceptible host

Sporadic

A disease that occurs without regularity