Submitted to: Veterinary Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/30/2007
Publication Date: 3/1/2008
Citation: Sundar, N., Asmundsson, I.M., Thomas, N.J., Samuel, M.D., Dubey, J.P., Rosenthal, B.M. 2007. Modest genetic differentiation among North American populations of Sarcocystis neurona may reflect expansion in its geographic range. Veterinary Parasitology. 152:8-15. Interpretive Summary: Sarcocystis species are single celled parasites that cause illness in humans and livestock. Humans and other hosts can become infected with this parasite by ingesting infected tissues. Herbivores can become infected by ingesting food and water contaminated with the resistant parasite stages excreted in feces of infected humans.Sarcocystis neurona causes a fatal disease in horses and other mammals. Scientists at the Beltsville Agricultural Research Center and Us Fish and Wildlife report genetic characterization of S. neurona from sea otters, raccoons and skunk. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: Sarcocystis neurona is an important cause of neurological disease in horses (equine protozoal myeloencephalitis, EPM) and sea otters in the United States. In addition, EPM-like disease has been diagnosed in several other land and marine mammals. Little genetic diversity among isolates of S. neurona from different hosts has been reported. Here, we used 11 microsatellites to characterize S. neurona DNA isolated from natural infections in 22 sea otters (Enhydra lutris) from California and Washington and in 11 raccoons (Procyon lotor) and one striped skunk (Mephitis mephitis) from Wisconsin. By jointly analyzing these 34 isolates with 26 isolates previously reported, we determined that geographic barriers may limit S. neurona dispersal and that only a limited subset of possible parasite genotypes may have been introduced to recently established opossum populations. Moreover, our study confirms that diverse, sympatric hosts share a common infection source, the opossum (Didelphis virginiana).