Epizootic

Definition

A sudden, widespread increase in disease incidence within a nonhuman animal population, analogous to an epidemic in humans. In entomological and veterinary contexts, epizootics often involve arthropod-borne pathogens where vector population surges or environmental conditions trigger rapid transmission. The term distinguishes animal disease outbreaks from human epidemics and may scale to panzootic when transnational.

Etymology

Greek epi- (upon) + zōion (animal) + -otic (disease condition)

Example

An epizootic of epizootic hemorrhagic disease (EHD) in white-tailed deer populations often follows periods of drought that concentrate deer and Culicoides biting midge vectors around limited water sources, accelerating virus transmission.

Synonyms

• animal epidemic

Related Terms

• enzootic
• Panzootic
• Vector
• pathogen reservoir
• disease ecology
• Arbovirus

Usage Notes

Contrasts with enzootic (disease maintained at baseline levels in a population). Applied to any nonhuman animals, including insects and other arthropods when discussing pathogens like microsporidia or baculoviruses in managed or wild populations. Not used for human disease; specialists maintain this distinction rigorously.