Fulminant type A viral hepatitis in a chimpanzee.

A case of a chimpanzee with fulminant hepatitis caused by spontaneous hepatitis A virus (HAV) infection was reported. The liver at autopsy revealed massive liver cell necrosis with mononuclear and polymorphonuclear cell infiltration. Aggregation of HAV-like particles (22-25 nm in diameter) were found within the vesicles of hepatocytes under the electron microscope. Immunofluorescent examination of the liver showed positive staining for HAV antigen, C1q, C3, C4, immunoglobulin M (IgM), and immunoglobulin G (IgG) in the hepatocytes and/or Kupffer cells in a granular fashion. The anti-HAV antibody (IgM type) and circulating immune complexes were detected in the postmortem serum. The present study suggests the possibility that the deposition of immune complexes of HAV and anti-HAV antibody in the liver cell plays an important role in the pathogenesis of massive liver cell necrosis in fulminant type A viral hepatitis.