Question
Negri bodies
Answer
Negri bodies are characteristic eosinophilic, round-to-oval intracytoplasmic inclusion bodies found within neurons infected with rabies virus, representing sites of active viral replication — historically the classical histopathological finding used to confirm rabies diagnosis.
Location: most characteristically demonstrated in the large pyramidal neurons of the hippocampus (Ammon’s horn) and Purkinje cells of the cerebellum.
Demonstration: classically identified on H&E staining of brain tissue (post-mortem); Seller’s stain was a specific historical method used to enhance visualization.
Diagnostic significance and limitations: their absence does NOT exclude rabies (they may be absent in a proportion of genuinely rabid cases) — modern diagnosis has largely superseded histopathological demonstration with the Direct Fluorescent Antibody (DFA) test on brain tissue (the current gold standard) and RT-PCR.