Location: Animal Parasitic Diseases LaboratoryTitle: Ancient, globally distributed lineage of Sarcocystis from sporocysts of the Eastern rat snake (Pantherophis alleghaniensis) and its relation to neurological sequalae in intermediate hosts
Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2016
Publication Date: 7/20/2016
Citation: Verma, S., Lindsay, D., Rosenthal, B.M., Dubey, J.P. 2016. Ancient, globally distributed lineage of Sarcocystis from sporocysts of the Eastern rat snake (Pantherophis alleghaniensis) and its relation to neurological sequalae in intermediate hosts. Parasitology Research. 115:2697-2704.
Interpretive Summary: Toxoplasma and Sarcocystis are related single celled parasites of livestock and humans. While Toxoplasma has long been recognized to cause neurologic disease in many warm blooded hosts, including humans, recently a mysterious illness has been reported in humans that had a history of travel to Malaysian region. These patients had symptoms simulating toxoplasmosis. Results for toxoplasmosis testing were negative and Sarcocystis parasite was found in muscle biopsies of some of these patients. Epidemiological data suggested a link to ingestion of food and water contaminated with Sarcocystis (sporocysts) excreted in feces of snakes. Nothing is known of Sarcocystis infection in snakes in the USA. The authors report Sarcocystis parasites in feces of rat snake (Pantherophis alleghaniensis). Molecularly, the parasite in rat snake has similarities to parasites in snakes in Malaysia. Feeding of these snake parasites induced a neurological illnessin mice. The results will be of interest to biologists, and parasitologists.
Technical Abstract: There is an emerging concern that snakes are definitive hosts of certain species of Sarcocystis that cause muscular sarcocystosis in human and non-human primates. Sarcocystis oocysts/sporocysts were found in the intestinal contents of 2 rat snakes (Pantherophis alleghaniensis) from Maryland, USA. The oocysts/sporocysts were orally infective for interferon gamma gene knockout (KO) mice, but not to outbred Swiss Webster mice. The KO mice developed neurological signs, and were necropsied between 33 to 52 days post inoculation (p.i). Only schizonts/merozoites were found, and they were confined to the brain. The predominant lesion was meningoencephalitis characterized by perivascular cuffs granulomas, and necrosis of the neuropil. The schizonts and merozoites were located in neuropil, and apparently extra vascular. Brain homogenates from infected KO mice were infective to KO mice and CV-1 cell line. DNA extracted from infected mouse brain, and infected cell cultures revealed the highest identity with Sarcocystis species that employ snakes as definitive hosts. This is the first report of Sarcocystis infection in the endangered rat snake (P. alleghaniensis) and first report of neurological sarcocystosis in mice induced by feeding sporocysts from a snake.