Pulmonary cryptosporidiosis in simian immunodeficiency virus-infected rhesus macaques.

Cryptosporidiosis is a common opportunistic infection in the gastrointestinal tract of human and nonhuman primates with AIDS. Pulmonary infection associated with Cryptosporidium spp. has not been previously reported in monkeys. Two macaques experimentally infected with simian immunodeficiency virus (SIV) had lesions containing cryptosporidial organisms involving the trachea, lungs, bile ducts, pancreas, and intestine. The pulmonary sections revealed moderate to severe bronchopneumonia associated with cryptosporidiosis. Numerous 2-4 microm oval Cryptosporidium spp. organisms were present in the cytoplasm of alveolar macrophages, multinucleated giant cells, and intestinal epithelial cells. Giant cells were positive for SIV by in situ hybridization. These are the first reported cases of cryptosporidiosis with involvement of pulmonary parenchyma in SIV-infected macaques.