enzootic

Enzootic is a term used in veterinary and ecological epidemiology to describe a disease that is regularly present within a particular animal population or geographic area. An enzootic disease is maintained at a relatively constant baseline level of incidence over time, rather than causing large, sudden outbreaks. The term is analogous to endemic disease in humans, but specifically refers to non-human populations and often involves animal reservoirs or vector species.

Enzootic transmission may involve reservoirs in wildlife, domestic animals, or arthropod vectors, and spillover into other species can occur, including humans in some cases. When conditions favor widespread transmission, case numbers can rise, producing epizootics or expanding enzootic transmission; conversely, favorable control measures or environmental changes can reduce incidence.

Common examples include bovine tuberculosis in regions where it remains endemic among cattle and wildlife reservoirs, enzootic West Nile virus circulation in birds and mosquitoes in many areas, and various enzootic infections in small mammals that may occasionally spill over to humans. However, the specific pattern of enzooticity can vary by species, geography, and time.

Management of enzootic diseases relies on surveillance to monitor baseline levels, vaccination or treatment where available, vector control, biosecurity practices, and wildlife management to reduce transmission. The term derives from Greek roots meaning "in animals" (zoon) and "pertaining to" (otic).