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In epidemiology and infectious diseases, the time during which an infectious agent is transmissible, directly or indirectly, from an infected person or animal to a susceptible person.
See also: period
n the period when the infectious agent that causes a communicable disease may be transmitted to a susceptible host, such as in diseases that initially involve the mucous membrane (e.g., diphtheria and scarlet fever). The period of communicability is from the time of exposure to the disease until termination of the carrier state, if one develops.