Gastrointestinal cryptosporidiosis in captive psittacine birds in the United States: a case review.

Histopathologic analysis performed on tissue samples from 34 captive psittacine birds over a 14-year period demonstrated gastrointestinal cryptosporidiosis. Although 8 birds had died unexpectedly, at least 10 showed gastrointestinal signs before death. Most birds had other significant pathologic lesions, unrelated to cryptosporidiosis, in which case Cryptosporidium was likely a secondary pathogen. However, in 11 birds the only significant histopathologic finding was gastrointestinal cryptosporidiosis. In 2 lovebird (Agapornis species) cases, direct sequencing of proventricular samples confirmed the presence of Cryptosporidium avian genotype III. A description and analysis of the pathologic findings in these 34 birds, as well as a review of avian gastrointestinal cryptosporidiosis, is provided.