The Collaborative International Dictionary of English v.0.48:

coccidiosis \coccidiosis\ n. (Med.)
   any of a group of infectious diseases caused by protozoan
   parasites (coccidia) of the order Coccidia, which infect
   the intestines of birds, dogs, and other vertebrates.
   [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

coccidiosis
    n 1: (veterinary medicine) infestation with coccidia