Laboratory investigation of human deaths from vampire bat rabies in Peru

In the spring of 1996, multiple cases of an acute febrile illness resulting in several deaths in remote locations in Peru were reported to the Centers for Disease Control and Prevention (CDC). The clinical syndromes for these cases included dysphagia and encephalitis. Because bat bites were a common occurrence in the affected areas, the initial clinical diagnosis was rabie s. However, rabies was discounted primarily because of reported patient rec overy. Samples of brain tissue from two of the fatal cases were received at CDC for laboratory confirmation of the rabies diagnosis. An extensive arra y of tests on the formalin-fixed tissues confirmed the presence of both rab ies viral antigen and nucleic acid. The virus was shown to be most closely related to a vampire bat rabies isolate. These results indicate the importa nce of maintaining rabies in the differential diagnosis of acute febrile en cephalitis, particularly in areas where exposure to vampire bats may occur.