ARS | Publication request: Sarcocysts of An Unidentified Species of Sarcocystis in Sea Otter (Enhydra Lutris)

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 23, 2002
Publication Date: January 15, 2003
Citation: Dubey, J.P., Lindsay, D.S., Rosenthal, B.M., Thomas, N.J. 2003. Sarcocysts of an unidentified species of sarcocystis in sea otter (enhydra lutris). Journal of Parasitology. 89:397-399.

Interpretive Summary: Sarcocystis neurona is a single celled parasite of animals. It causes a fatal neurologic disease in horses and several other species of animals including sea mammals. Sea otters were recently identified as a host for S. neurona. Scientists at the Beltsville Agricultural Research Center and the Virginia Tech, Blacksburg describe another species of Sarcocystis parasites in sea otter and differentiate it molecularly and morphologically from S. neurona. These findings will be of interest to biologists, parasitologists and wildlife workers.

Technical Abstract: The number of Sarcocystis species that infect sea otters (Enhydra lutris) is unknown. Sea otter tissues were recently shown to harbor sarcocysts of Sarcocystis neurona and of unidentified species of Sarcocystis. Whereas sarcocysts of S. neurona have walls 1-3 µm thick with Type 9 villar protrusions, ultrastructure of a distinct thin-walled sarcocyst (0.5 - 0.7 µm thick) lacking villar protrusions but instead exhibiting minute Type 1 undulations on the sarcocyst wall is described in this report. Parasites characterized from a sea otter infection were inferred to be related to, but distinct from, other species belonging to the genus Sarcocystis based on sequencing and phylogenetic analysis of a portion of the beta subunit of the plastid-encoded RNA polymerase gene.