Figure 14-80.

Equine Herpesvirus 1 Myeloencephalopathy, Brain, Midsagittal Section.

A, Hemorrhage, brainstem, horse. Focal or multifocal areas of hemorrhage and/or necrosis (arrow) are characteristic of equine herpesvirus encephalitis but also occur in equine arteritis virus encephalitis, cerebrospinal nematodiasis, and equine protozoal encephalomyelitis (Sarcocystis neurona). B, Vasculitis and hemorrhage, brainstem, horse. Vasculitis is the primary lesion. The virus localizes in small arteries, venules, and capillaries of the central nervous system, resulting in vasculitis and fibrinoid necrosis, which at times leads to thrombosis and focal infarction of the brain and spinal cord. H&E stain.

(A courtesy College of Veterinary Medicine, University of Illinois. B courtesy Dr. J. Simon, College of Veterinary Medicine, University of Illinois.)