Systematic Veterinary Virology

EEE & WEE

• The extent of the lesions depends on the severity of the infection and the duration of the neurological involvement.
• Gross pathological lesions are rarely observed in horses and, if present, consist only of the congestion of the brain and meninges.
• Ecchymotic haemorrhages of traumatic origin may also be observed. Microscopic lesions are usually found throughout the central nervous system, which include inflammatory response involving the grey matter, neuronal degeneration with infiltration by polymorphonuclear leukocytes, diffuse and focal gliosis, perivascular cuffing with lymphocytes and neutrophils, neuronophagia and liquefaction of the neutrophils.