fistula vs animal disease

fistula and animal disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
fistula	Yes	No	No	No
animal disease	Yes	No	No	No

As nouns, animal disease is a hypernym of fistula; that is, animal disease is a word with a broader meaning than fistula:

fistula (noun)	animal disease (noun)
an abnormal passage leading from a suppurating cavity to the body surface	a disease that typically does not affect human beings
a chronic inflammation of the withers of a horse