Rabies encephalitis in a patient with no history of exposure

A 29-year-old man died of a rapidly progressive encephalitis without a clinical diagnosis and without a history of exposure to the rabies virus. A diagnosis of rabies was established postmortem by histologic and ultrastructural demonstration of rabies virus inclusions, by fluorescent antibody reaction, and by viral culture. Viral inclusions were sparse, were generally irregular and poorly demarcated, and were confined almost exclusively to the cerebellar Purkinje cells. A history of exposure was obtained only in retrospect on detailed questioning of friends and relatives. Rabies encephalitis is now seen most frequently in patients without a history of exposure and may be easily overlooked both clinically and pathologically.