Epidemiological Survey

a medical survey conducted in an epidemic focus to discover the source of an infection, the means by which the causative agent was transmitted, and the circumstances that gave rise to the disease. The findings are used to devise ways of preventing the disease from spreading. The survey is conducted by an epidemiologist (or an assistant to the epidemiologist-physician) or by a district physician. Hygienists, sanitary engineers, and other specialists may be called in to assist.

Individuals stricken by the disease and those persons who have had contact with them are interviewed. The latter also undergo laboratory testing. The survey may also include tests on objects from the environment, entomological and—in the case of zoonoses—epizootic surveys, and inspection of water sources. In the case of intestinal infections, restaurants and other places where food is prepared are inspected. The characteristics of the disease and the number of sick persons determine the type of survey to be conducted.

The results of the survey are recorded on an epidemiological survey map. The findings determine the actions to be taken with respect to the individuals who have had contact with sick persons (medical observation, isolation, immunization, chemoprophylaxis). They also determine disinfection measures and steps to improve the sanitary condition and maintenance of water-supply facilities and food-service facilities. The findings are also used to study the patterns of distribution of infectious diseases and to devise control measures.