title: Sarcocystis neurona schizonts-associated encephalitis, chorioretinitis, and myositis in a two-month-old dog simulating toxoplasmosis, and presence of mature sarcocysts in muscles.
abstract: Sarcocystis neurona is an unusual species of the genus Sarcocystis. Opossums (Didelphis virginianus, D. albiventris) are the definitive hosts and several other species, including dogs, cats, marine mammals, and horses are intermediate or aberrant hosts. Sarcocysts are not known to form in aberrant hosts. Sarcocystis neurona causes fatal disease in horses (Equine Protozoal Myeloencephalitis, EPM). There are numerous reports of fatal EPM-like infections in other species, usually with central nervous system signs and associated with the schizont stage of S. neurona. Here, we report fatal disseminated S. neurona infection in a nine-week-old golden retriever dog from Mississippi, USA. Protozoal merozoites were identified in smears of the cerebrospinal fluid. Microscopically, lesions and protozoa were identified in eyes, tongue, heart, liver, intestines, nasal turbinates, skeletal muscle and brain, which reacted intensely with S. neurona polyclonal antibodies. Mature sarcocysts were seen in sections of muscles. These sarcocysts were ultrastructurally similar to those of S. neurona from experimentally infected animals. These data suggest that the dog is another intermediate host for S. neurona. Data suggest that the dog was transplacentally infected.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA. Electronic address: Jitender.Dubey@ars.usda.gov.
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.affiliation: College of Veterinary Medicine, Mississippi State University, 240 Wise Center Drive, Mississippi State, MS 39762, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Black
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Verma
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA.
authors.forename: R
authors.initials: R
authors.lastname: Calero-Bernal
authors.affiliation: Joint Pathology Center, Veterinary Pathology Services, 606 Stephen Sitter Avenue, Silver Spring, MD 20910, USA.
authors.forename: E
authors.initials: E
authors.lastname: Morris
authors.affiliation: Joint Pathology Center, Veterinary Pathology Services, 606 Stephen Sitter Avenue, Silver Spring, MD 20910, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Hanson
authors.affiliation: College of Veterinary Medicine, Mississippi State University, 240 Wise Center Drive, Mississippi State, MS 39762, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Cooley
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002825:Chorioretinitis / Q000209:etiology / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis / Q000469:parasitology* / Q000473:pathology; D004285:Dogs; D004660:Encephalitis / Q000209:etiology / Q000662:veterinary*; D046529:Microscopy, Electron, Transmission; D008922:Mississippi; D018482:Muscle, Skeletal / Q000469:parasitology*; D009220:Myositis / Q000209:etiology / Q000662:veterinary*; D012522:Sarcocystis / Q000166:cytology / Q000502:physiology*; D012523:Sarcocystosis / Q000150:complications / Q000469:parasitology / Q000662:veterinary*; D052939:Schizonts / Q000648:ultrastructure
chemical_list: D000913:Antibodies, Protozoan
keywords: Dog; Electron microscopy; Immunoreactivity; Sarcocystis neurona; Sarcocysts; Schizonts