Quarantine

Quarantine, period during which a person or animal must be kept under observation in isolation from the community after having been in contact with an infectious disease. The duration of quarantine depends on the disease(s) concerned and their maximum length of incubation. The term derives from the period of 40 days that ships had to wait before their crews could disembark at medieval European ports, due to fear of their carrying plague.

See also: Epidemic.