Meaning

adjective (of animals) epidemic among animals of a single kind within a particular region

originFrom French épizootique, animal equivalent of epidemic, from épizootie, irregularly formed from Ancient Greek ἐπί (epí) + ζῷον (zōîon, “animal”). By surface analysis, epi- + zo- + -otic. Use of the word in the second sense, "an ailment", was likely originally a reference to a particular epizootic ailment. Both senses are attested since at least the 1800s, and the pronunciation with five syllables…

Etymology from Wiktionary, CC BY-SA 3.0