|SYKES, JANE - University Of California|
|SHELTON, DIANE - University Of California|
|VERMA, SHIV - Non ARS Employee|
|VIVIANO, JANE - Non ARS Employee|
|SUNDAR, NATRAJAN - National Institutes Of Health (NIH)|
|GRIGG, MIKE - National Institutes Of Health (NIH)|
Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2014
Publication Date: 10/27/2014
Citation: Dubey, J.P., Sykes, J., Shelton, D., Verma, S., Viviano, J., Sundar, N., Grigg, M. 2014. Sarcocystis caninum and Sarcocystis svanai n. spp. (Apicomplexa: Sarcocystidae) associated with severe myositis and hepatitis in the domestic dog (Canis familiaris). Journal of Parasitology. 62(3):307-17.
Interpretive Summary: Species of the genus Sarcocystis are single celled parasites, closely related to Toxoplasma. Some Sarcocystis species cause serious illness in livestock and humans. Recently, severe myositis has been reported in pet dogs but the associated parasite has not been identified. In the present paper scientists identified 2 new species of Sarcocystis in dogs and defined their diagnostic features. The results will be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: Sarcocystis species have a 2-host life cycle with carnivores as definitive hosts and herbivores as intermediate hosts. Occasionally dogs are definitive as well as intermediate hosts for Sarcocystis species. There are several reports of Sarcocystis sarcocysts in muscles of dogs but these species have not been named. Here, we propose 2 new names, Sarcocystis caninum, and Sarcocystis svanai for sarcocysts associated with clinical muscular sarcocystosis in 2 domestic dogs (Canis familiaris) from Montana and Colorado. Only the sarcocyst stage was identified. Most of the sarcocysts were S. caninum. DNA was extracted from infected frozen muscle biopsies. Both dogs possessed identical sequences at the ITS1 locus, and BLASTn analysis established that the sarcocysts identified in these dogs were markedly different from other coccidian species. Sarcocystis caninum sarcocysts were up to 1.2 mm long and up to 75 µm wide. The sarcocyst wall was 1-2 µm thick and contained villar protrusions that lacked microtubules. Bradyzoites in sections were 7-8 µm long. Sarcocysts of S. svanai were few, but structurally distinct from S. caninum. Sarcocystis svanai sarcocysts were thin walled (<0.5 µm), and the wall lacked villar protrusions but has tiny undulations that did not invaginate.