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United States Department of Agriculture

Agricultural Research Service

Title: Pyogranulomatous Encephalitis Associated with An Unidentified Sarcocystis Neurona-Like Organism in a Horse

Authors
item Hamir, A - OREGON STATE UNIVERSITY
item Gerros, T - OREGON STATE UNIVERSITY
item Dubey, Jitender

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 5, 1997
Publication Date: N/A

Interpretive Summary: Infections by protozoa (single celled organisms) of the genus Sarcocystis are widespread in livestock. Most animals infected with Sarcocystis do not have clinical signs. An unusual species of Sarcocystis, Sarcocystis neurona, infection causes a fatal disease in horses (called EPM) in the United States. Scientists at the Beltsville Agricultural Research Center and Oregon State University report an unidentified parasite causing neurological disease in a horse. The results of this paper will be helpful to equine clinicians and veterinary pathologists.

Technical Abstract: A 15-year old Morgan cross Arabian mare became ataxic and progressively deteriorated over a 4 week period. The mare was euthanized because of poor prognosis and necropsied. In the brain there were areas of hemorrhage, necrosis and mononuclear cell infiltrates. Protozoal schizonts were seen in endothelial cells and in unidentified cells. These organisms did not react with anti-Sarcocystis neurona serum in an immunohistochemical test.

Last Modified: 9/22/2014