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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #269194

Title: Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni)

item Dubey, Jitender
item THOMAS, N - Us Geological Survey (USGS)

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2011
Publication Date: 12/1/2011
Citation: Dubey, J.P., Thomas, N.J. 2011. Sarcocystis neurona retinochoroiditis in a sea otter (Enhydra lutris kenyoni). Veterinary Parasitology. 183:156-159.

Interpretive Summary: Sarcocystis neurona is a single-celled parasite, very closely related to Neospora caninum and Toxoplasma gondii. It causes a fatal disease in horses and companion animals. Its diagnosis in living animals is difficult. In the present paper authors report first case of sarcocystosis affecting the eyes of sea otter. The results will be of interest to biologists, parasitologists, and veterinarians.

Technical Abstract: Sarcocystis neurona is an important cause of fatal disease in sea otters in the USA. Encephalitis is the predominant lesion and parasites are confined to the central nervous system and muscles. Here we report retinochoroiditis in a sea otter (Enhydra lutris kenyoni) found dead on Copalis Beach, WA, USA. Salient lesions were confined to the brain and eye. Multifocal nonsuppurative meningoencephalitis was present in the cerebrum and cerebellum associated with S. neurona schizonts. The retina of one eye had a focus of inflammation that contained numerous S. neurona schizonts and merozoites. The focus extended from the retinal pigment epithelium inward through all layers of the retina, but inflammation was most concentrated at the inner surface of the tapetum and the outer retina. The inner and outer nuclear layers of the retina were disorganized and irregular at the site of inflammation. There was severe congestion and mild hemorrhage in the choroid, and mild hemorrhage into the vitreous body. Immunohistochemistry with S. neurona-specific polyclonal rabbit antibodies stained schizonts and merozoites. To our knowledge this is the first report of S. neurona-associated retinochoroiditis in any naturally infected animal.