Source : Webster's Revised Unabridged Dictionary (1913)

Enzootic \En`zo*["o]t"ic\, a. [Gr. ? in + ? an animal: cf. F.
   enzo["o]tique.]
   Afflicting animals; -- used of a disease affecting the
   animals of a district. It corresponds to an endemic disease
   among men.

Source : WordNet®

enzootic
     adj : of a disease that is constantly present in an animal
           community but only occurs in a small number of cases