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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Approach to the Detection and Control of Foodborne Parasites and the Impact on Food Safety

Location: Animal Parasitic Diseases

Title: Redescription of Sarcocystis fusiformis sarcocysts from the water buffalo (Bubalus bubalis)

Authors
item Dubey, Jitender
item Hilali, Moussad -
item Van Wilpeerna, -
item Verma, Shiv -
item Calero-Bernal, Rafael -
item Adel-Wahab, Abdel -

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 16, 2014
Publication Date: N/A

Interpretive Summary: Sarcocystis and Toxoplasma are closely related, single celled parasites that share common hosts. Some species of Sarcocystis are zoonotic and of public health concerns. Recently, human volunteers who ate raw buffalo meat became sick. Cattle and buffaloes harbor multiple species of Sarcocystis, but there is considerable confusion concerning the identity of some ot these species. In the present report,scientists from ARS, in collaboration with scientists from Africa, redescribe the morphology of one of the Sarcocystis species in buffaloes. The results will be of interest to biologists and parasitologists.

Technical Abstract: Five species of Sarcocystis have been reported from the water buffalo (Bubalus bubalis): Sarcocystis fusiformis and Sarcocystis buffalonis have macrocysts and cats act as definitive hosts; Sarcocystis levinei has microcysts and dogs act as definitive host; Sarcocystis dubeyi and S. sinensis have microcysts; their definitive host is unknown. The ultrastructure of sarcocyst is a useful criterion to distinguish Sarcocystis species within a given host. Here, we redescribe the structure of S. fusiformis sarcocysts by scanning and transmission electron microscopy (SEM, TEM). Nine macroscopic sarcocysts from esophagus of S. fusiformis from the water buffalo in Egypt were examined by light microscopy, SEM, and TEM. The sarcocyst wall was up to 9 µm thick, depending on the section and the technique. In 5 µm paraffin embedded sections, the cyst wall was indistinct, 2-5 µm thick, and appeared smooth. In 1 µm plastic embedded sections stained with Toluidine blue, the sarcocyst wall was 2.5 to 5.2 µm thick and had branched villar protusions (vp) like branches of a dead tree. By SEM, the sarcocyst wall had a mesh-like structure with irregularly shaped vp that were folded over the sarcocyst wall. On each vp there were uniform papillomatous structures that were 100 nm wide. By TEM, vp were up to 6 µm long and contained filamentous tubular structures, most of which were parallel to the long axis of the projections; granules were absent from these tubules. By TEM, bradyzoites within the same cyst varied from 11.2 to 16.8 µm in length. By TEM, bradyzoites had a very long (10 µm) convoluted mitochondrium, up to 12 dense granules, but only 2 rhoptries. This redescription should help to differentiate the sarcocysts of S. fusiformis from similar sarcocysts in domestic and wild bovids and ruminants.

Last Modified: 10/31/2014
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