title: Modest genetic differentiation among North American populations of Sarcocystis neurona may reflect expansion in its geographic range.
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. Opossums are its only definitive hosts. 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 1 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 intermediate hosts share a common infection source, the opossum (Didelphis virginiana).
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Animal Natural Resources Institute, Animal Parasitic Diseases Laboratory, Beltsville, MD 20705-2350, USA.
authors.forename: N
authors.initials: N
authors.lastname: Sundar
authors.forename: I M
authors.initials: IM
authors.lastname: Asmundsson
authors.forename: N J
authors.initials: NJ
authors.lastname: Thomas
authors.forename: M D
authors.initials: MD
authors.lastname: Samuel
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: B M
authors.initials: BM
authors.lastname: Rosenthal
mesh_terms: D000818:Animals; D001921:Brain / Q000469:parasitology; D002140:California; D020808:Central Nervous System Protozoal Infections / Q000469:parasitology / Q000635:transmission / Q000662:veterinary; D016000:Cluster Analysis; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004197:Disease Reservoirs / Q000469:parasitology / Q000662:veterinary; D004679:Encephalomyelitis / Q000469:parasitology / Q000662:veterinary; D014644:Genetic Variation; D006790:Host-Parasite Interactions; D012889:Mephitidae / Q000469:parasitology*; D018895:Microsatellite Repeats; D010041:Otters / Q000469:parasitology*; D010802:Phylogeny; D011821:Raccoons / Q000469:parasitology*; D012522:Sarcocystis / Q000145:classification / Q000235:genetics*; D012523:Sarcocystosis / Q000469:parasitology / Q000662:veterinary*; D014059:Tongue / Q000469:parasitology; D014861:Washington
chemical_list: D016054:DNA, Protozoan