Pteropid lyssaviral infection, lead poisoning, and the difficulties in diagnosing pteropid lyssaviral infection using histopathological examination of tissues are described in wild black flying foxes (Pteropus alecto) from northern Queensland (Australia). An adult female P. alecto showed aggression before death in January 1995. Lead poisoning was diagnosed due to the presence of intranuclear lead inclusion bodies in renal proximal convoluted tubular epithelium and high concentrations of lead in renal and hepatic tissues, 370.03 +/- 7.35 ppm and 16.76 +/- 0.53 ppm, respectively. Renal inclusion bodies were composed of lead, calcium, phosphorus, and possibly sulphur; some inclusions had their granules arranged in concentric bands. This bat also had a moderate concentration (8.09 +/- 0.18 ppm) of cadmium in renal tissue. An adult male P. alecto presented with ascending paralysis before it died in May 1996. Pteropid lyssaviral infection was diagnosed subsequently in both bats in September 1996 by immunofluorescent and immunoperoxidase antibody tests for rabies on brains and viral culture from brains. Neither bat had gross or microscopic lesions of the brain that suggested a lyssaviral infection, apart from occasional, subtle, eosinophilic cytoplasmic inclusions in the neurones of the brain stem of the female. These cases illustrate the need for a specific test to detect pteropid lyssavirus such as an immunofluorescent antibody test for lyssavirus rather than histopathological examination of tissues.