Simian adenoviral pneumonia.

In the past 6 years we have encountered 26 cases of fatal adenoviral pneumonia in six species of simian primates. O these, 22 animals were between 11 and 38 days old at the time of death, and pneumonia was the primary clinical disease. The spectrum of clinical disease varied from peracute fatal disease to inapparent disease with seroconversion. In one outbreak involving 4 infants housed together in an isolation unit, simian virus 11 was isolated from 3 of the infants and seroconversion occurred in all 4. At necropsy the lungs were voluminous, with firm gray areas of consolidation. On histopathologic examination, severe patchy necrotizing alveolitis and bronchiolitis were present. Variable edema and hyaline membrane formation, alveolar epithelial hyperplasia, and secondary bacterial pneumonia were also seen. Large basophilic intranuclear inclusions were present in bronchiolar and alveolar epithelial cells in all 26 cases. In 4 of 8 cases examined ultrastructurally typical intranuclear paracrystalline arrays of adenoviral virions were demonstrated. Intranuclear inclusion bodies were also observed occasionally in bile duct and pancreatic duct epithelium. Simian adenoviral pneumonia can be a spontaneous disease problem in laboratory-reared primates and offers excellent potential as an animal model of human adenoviral pneumonia.