Concurrent cryptosporidiosis and chicken anaemia virus infection in broiler chickens.

Concurrent infection with Cryptosporidium baileyi and chicken anaemia virus (CAV) was observed in a flock of 8000 4-week-old broiler chickens. The birds, showing overt symptoms of stunted growth and 25% mortality from hatching to 4 weeks of age, harboured the protozoan in the epithelial cells of the bursa of Fabricius and the urodeal portion of the cloaca. This is the first report on an outbreak of avian cryptosporidiosis associated with CAV.