CONTROL OF EPIDEMICS
The first principle of control is recognition of the existence of an epidemic. This recognition is sometimes immediate because of the high incidence of disease, but often the evi- dence is obtained from ongoing surveillance activities, such as routine disease reports to health departments and records of school and work absenteeism. The causative agent must be identified and studies to determine route of transmission (eg, food poisoning) must be initiated.
Measures must then be adopted to control the spread and development of further in- fection. These methods include (1) blocking the route of transmission if possible (eg, improved food hygiene or arthropod control); (2) identifying, treating, and, if necessary, isolating infected individuals and carriers; (3) raising the level of immunity in the unin- fected population by immunization; (4) making selective use of chemoprophylaxis for subjects or populations at particular risk of infection, as in epidemics of meningococcal infection; and (5) correcting conditions such as overcrowding or contaminated water sup- plies that have led to the epidemic or facilitated transfer.