Epizootic

An epizootic is a disease event in a nonhuman animal population that is analogous to an epidemic in humans, a term used in the field of epizoology. Such an event can be a localized outbreak, a more widespread epizootic, or, if it spreads across a very large area, a panzootic, and high population density is a major contributing factor, which is why aquaculture is especially vulnerable. Whether an event counts as an epizootic involves judgment by health authorities weighing new cases against the historical rate of the disease, since a few cases of a rare disease might qualify while many cases of a common disease would not, and this is distinguished from an enzootic disease, which occurs consistently at a high rate in a given population. A documented example is the 1990 outbreak of Newcastle disease among double crested cormorants on the Great Lakes, which killed about ten thousand birds.