Gross

Minimal pathological findings. The carcass may be emaciated; there may evidence of self-trauma; and in dogs particularly there may be foreign bodies in the alimentary tract because of pica.





Histopathology

• Diffuse encephalitis with mononuclear cell perivascular cuffing and focal gliosis, i.e. an inflammatory response typical of any non-suppurative infection of the brain. Spongiform lesions in the brains of rabid animals have also been reported.
• Neuronal degeneration in rabies is relatively severe compared with some other viral infections of the CNS, particularly in carnivores.
• Negri bodies. Neurones may contain the pathognomonic intracytoplasmic inclusions: 'Negri bodies'. These may occur in several areas of the brain but are most prominent in the hippocampus. In cats some confusion may arise as similar inclusions may be seen in some nerve cells in normal cats. Negri were used extensively in diagnosis of rabies, but this has now been superseded in most countries by more reliable and rapid techniques.
• Other changes are minimal but may include ganglioneuritis in the vertebral ganglia and possible degenerative changes in the salivary gland.

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