Inflammation of the spinal cord and brain. See also encephalomyelitis
- equine herpesvirus m. — caused by some strains of equine herpesvirus 1. The lesions differ from other herpesvirus encephalidities in other species in that there are thrombi in small blood vessels, probably caused by viral antigen–antibody complexes and consequent anoxic changes, including loss of neurons. Called also equine herpesvirus encephalomyelitis.
- equine protozoal m. (EPM) — presents with focal or multifocal signs of neurologic disease involving the brain, brain stem and or spinal cord. It is caused most commonly by Sarcocystis neurona but occasionally by Neospora caninum or the closely related N. hughesi. The definitive host for S. neurona in North America is the North American possum Didelphis virginiana and in South America D. marsupialis and D. albiventris. The disease is more common in the summer, may be acute or chronic, and there is great variation in clinical signs due to the ability of the organism to infect both white and gray matter at multiple sites in the central nervous system.
