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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #374359

Research Project: Detection and Control of Foodborne Parasites for Food Safety

Location: Animal Parasitic Diseases Laboratory

Title: Gamogony of Sarcocystis strixi in mammalian cell cultures

item LINDSAY, DAVID - Virginia Tech
item Dubey, Jitender
item SCOTT, DAVID - Carolina Raptor Center
item ROSYPAL VON DOHLEN, ALEXA - (NCE, CECR)networks Of Centres Of Exellence Of Canada, Centres Of Excellence For Commercilization A

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2021
Publication Date: 7/20/2021
Citation: Lindsay, D.S., Dubey, J.P., Scott, D., Rosypal Von Dohlen, A. 2021. Gamogony of Sarcocystis strixi in mammalian cell cultures. Journal of Parasitology. 107(4):562-565.

Interpretive Summary: Coccidians are single celled parasites and this group includes genera, Eimeria, Neospora, Toxoplasma, and Sarcocystis that can cause severe disease in livestock. The genus Sarcocystis has more than 200 named species and some species can cause severe illness in livestock and some species are zoonotic. Sarcocystis species use 2 hosts in their life cycle. An intermediate host (herbivores) is infected after consuming sporulated oocysts/sporocysts excreted by definitive hosts (carnivores, omnivores). The sexual cycle of the parasite is restricted to the intestinal wall of the definitive hosts and this phase of the cycle is difficult to cultivate in invitro. Here, the authors had some success in growing the sexual stages of a bird Sarcocystis species. These results will be of interest to biologists and parasitologists.

Technical Abstract: We are interested in the disease ecology of Sarcocystis species that infect birds of prey as definitive and intermediate hosts, and the conditions necessary to support their life-cycle development. Here, we sought to understand how completely the sexual development of an avian species of Sarcocystis (Sarcocystis strixi) could be reproduced using bradyzoites derived from a gamma-interferon gene knockout (KO) mouse then grown in mammalian cell cultures, hoping to derive fully-sporulated oocysts. Sporocysts of S. strixi from a naturally-infected barred owl (Strix varia) were fed to KO mice to produce sarcocysts in KO mice. The contents of sarcocysts in abdominal and thigh muscles were obtained by acid-pepsin digestion. Bradyzoites, metrocytes and an unusual spherical stage were seen in digest before the inoculation of host cells. The spherical stages stained dark with Giemsa stain but no nucleus was observed and they were seen free in the digest sample or associated with the concave portion of bradyzoites. Examination of infected cell cultures demonstrated that gamonts were present at 16 hr, and that developing macrogamonts and microgamonts were present at 24 hr post-inoculation. Neither unsporulated nor sporulated oocysts were observed, dampening hopes of completing the sexual cycle in this model under these conditions. Avian cell cultures may prove more supportive of completing gametogony.