Incubation

Incubation, method of keeping microorganisms such as bacteria or viruses warm and in an appropriate medium to promote their growth (e.g., in identification of the organisms causing disease); also, period during which an organism is present in the body before causing disease. Infectious disease is contracted from a source of infective microorganisms. Once these have entered the body they divide and spread to different parts, and it may be some time before they cause symptoms due to local or systemic effects. This incubation period may be helpful in diagnosis and in determining length of quarantine periods.