The Collaborative International Dictionary of English v.0.48:

Epizootic \Ep`i*zo*["o]t"ic\, Epizooty \Ep`i*zo"["o]*ty\, n. [F.
   ['e]pizo["o]tie.]
   1. A contagious disease which attacks many animals at the
      same time; an epizootic disease; an epidemic among
      animals.
      [1913 Webster]

   2. A murrain; an epidemic influenza among horses.
      [1913 Webster]