PULMONARY-LESIONS IN EXPERIMENTAL OPHIDIAN PARAMYXOVIRUS PNEUMONIA OFARUBA ISLAND RATTLESNAKES, CROTALUS-UNICOLOR

Histologic and ultrastructural changes were observed in the respirator y portions of luna in five 29-40-month-old Aruba Island rattlesnakes, Crotalus unicolor; that were inoculated with an Aruba Island Rattlesna ke virus (AIV) strain of ophidian paramyxovirus (OPMV) isolated from a n Aruba Island rattlesnake. Lungs from one non-infected and three mock -infected Aruba Island rattlesnakes were examined also. From 4 to 22 d ays following intratracheal inoculation, progressive microscopic chang es were seen in the lung. Initially, increased numbers of heterophils were observed in the interstitium followed by proliferation and vacuol ation of epithelial cells lining faveoli. The changes appeared to prog ress from cranial to caudal portions of the respiratory lung following inoculation. Beginning at 4 days postinoculation, viral antigen was d emonstrated in epithelial cells lining faveoli with an immunofluoresce nt technique using a rabbit anti-AN polyclonal antibody. Electron micr oscopy revealed loss of type I cells, hyperplasia of type II cells, an d interstitial infiltrates of heterophils and mononuclear cells. Viral nucleocapsid material was seen within the cytoplasm and mature virus was seen budding from cytoplasmic membranes of infected type I and typ e II cells from 8 to 19 days after infection. A virus consistent with AN was isolated from lung tissues of infected rattlesnakes, thus fulfi lling Koch's postulates.