Rabies viral antigen in extracranial organs: a post-mortem study

Rabies is a communicable disease and a significant health hazard. Histopathological confirmation of the diagnosis depends on the demonstration of Negri bodies - characteristic intracytoplasmic inclusions. In cases where these are not seen, immunohistochemistry serves as a useful adjunct. After its establishment in the central nervous system, the rabies virus is known to reach peripheral organs by a centrifugal spread. The present study was undertaken with the aim of demonstrating rabies viral antigen (RVAg) in the extracranial organs. Eleven confirmed cases of rabies were analysed and RVAg was found in the adrenal glands, heart, gastrointestinal tract and pancreas, confirming the centrifugal spread of the virus. The detection of RVAg in the extracranial sites may serve as a useful tool in the ante-mortem diagnosis by subjecting the extracranial tissue to biopsy and subsequent immunohistochemistry.