What term describes an animal disease outbreak?

The term that best describes an animal disease outbreak is "epizootic." This term is specifically used to indicate a sudden increase in the number of cases of a disease within a particular animal population or geographical area, akin to how "epidemic" applies to human populations. When an epizootic occurs, it generally signifies that the disease is spreading rapidly and affecting a larger number of animals than what is typically expected in that population or region.

In contrast, "endemic" refers to a disease that is consistently present within a certain geographical area or among a specific population, but does not necessarily involve an outbreak or sudden surge in cases. "Epidemic" is a term that is typically reserved for human populations, denoting a significant increase in cases of a disease in humans. "Emergent" refers to diseases that are newly identified or are rapidly increasing in incidence or geographic range but does not specifically pertain to outbreak scenarios in animals. Therefore, "epizootic" is the precise term for describing an acute animal disease outbreak.