Abstract:
Cloacas of male ostrich chicks that had suffered prolapse of the phallus and cloaca were compared
with cloacas of normal ostrich chicks of both sexes from the same area. Heavy infection of the cloacal
and bursal tissue with Cryptosporidium sp. was present in all the cases of prolapse, while no cryptosporidia
were observed in the normal chicks. Histopathological lesions as described in cryptosporidial
infection in other species were present in the infected cloacas. These included loss of the microvillous
border and epithelial hyperplasia, and degeneration, which was indicated ultrastructurally by vacuolation
of the apical cytoplasm, swelling of organelles, and nuclear changes. It is suggested that these lesions,
in combination with the anatomy of the male ostrich cloaca, may be responsible for prolapse of the
phallus and cloaca.
