An epidemic (from the Greek: epi upon; demos, people) is usually defined as a large-scale, temporary increase in the occurrence of a disease in a community or region which is clearly in excess of normal expectancy, whereas a pandemic (pan, all) is the occurrence of a disease which is clearly in excess of normal expectancy and is spread over a whole geographical area, usually crossing national boundaries. The occurrence of cases of disease in excess is usually expected for a given period of time. Epidemics are commonly thought to involve outbreaks of acute infectious disease.
For infectious diseases, epidemics can occur when large numbers of susceptible persons are exposed to infectious agents in settings or under circumstances that permit the spread of the agent. Spread of an infectious disease depends primarily on the chain of transmission of an agent: a source of the agent, a route of exit from the host, a suitable mode of transmission between the susceptible host and the source, and a route of entry into another susceptible host. Modes of spread may involve direct physical contact between the infected host and the new host, or airborne spread,
An epidemic is a public health emergency requiring immediate investigation. The steps in investigating an epidemic are as follows:
Confirm the diagnosis.
Verify that the number of cases is outside normal expectations.
Define features in common among the cases (including in apparent cases).
Distinguish cases from members of the community who are not affected.
Compare the exposure history of the cases with a sample of non cases.
Conduct appropriate laboratory tests for pathogenic organisms.
Review environment and social conditions.
Arrange, classify, and analyze the data.
Plot graphs of time trends and the number of cases; create maps of the distribution of cases.
Report findings to the public health authorities for action to control the epidemic.
The best social service during spread-up of epidemic diseases are as follows:
a) Maintaining hygienic condition by cleaning, washing, disinfection action at the all areas.
b) Drinking pathogen free and poison free water for all people.
c) Affected people must be separate immediately and send to medical center.
d) Providing medical teams and medical centers at affected areas.
e) Vaccination for probable disease must be done in proper time.
f) Social awareness and motivation programme provide regularly.
