Epizootic
An epidemic outbreak of disease in an animal population, often with the implication that it may extend to humans.
For example, Rift Valley fever (RVF) primarily affects livestock and can cause disease in a large number of domestic animals -- an 'epizootic' -- and the presence of an RVF epizootic can lead to an epidemic among humans who are exposed to diseased animals.
The word 'epizootic' is pronounced ep´i-zo-ot´ik.
It has Greek roots: epi- meaning 'on' among other things, + zoon, 'animal.'