Figure 14-79.

Hemorrhagic Encephalitis and Myelitis, Eastern Equine Polioencephalomyelitis, Brainstem and Spinal Cord, Horse.

A, Brain, transverse section at the level of the hippocampus, horse. The gray matter of the brainstem has dark red to black discoloration as a result of congestion and hemorrhage. The lesion is the result of viral infection, which has an affinity for neurons; this virus also causes vascular necrosis followed by thrombosis, but this is not common. B, Spinal cord, horse. Note the red to brown discoloration of the gray matter in the dorsal and ventral horns (caused by congestion and hemorrhage). The lesion is the result of viral infection that has an affinity for neurons; however, this virus can also cause vascular necrosis followed by thrombosis.

(Courtesy College of Veterinary Medicine, University of Florida; and Noah's Arkive, College of Veterinary Medicine, The University of Georgia.)