|MORE, G - National University Of La Plata And Museum|
|VAN WILPE, E - University Of Pretoria|
|CALERO-BERNAL, R - Non ARS Employee|
|VERMA, SHIV - Non ARS Employee|
|SCHARES, G - Friedrich-Loeffler-institut|
Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2015
Publication Date: 7/24/2015
Citation: Dubey, J.P., More, G., Van Wilpe, E., Calero-Bernal, R., Verma, S.K., Schares, G. 2015. Sarcocystis rommeli, n. sp. (Apicomplexa: Sarcocystidae) from cattle (Bos taurus) and its differentiation from Sarcocystis hominis. Journal of Eukaryotic Microbiology. 63:62-68.
Interpretive Summary: Zoonosis caused by Toxoplasma, and related parasite Sarcocystis continues to be of public health concern. Sarcocystis is a single celled parasite. Two of the Sarcocystis species, S. hominis and S. suihominis are transmissible to humans by eating raw/undercooked beef or pork, respectively. After ingestion of infected beef or pork humans excrete an environmentally resistant stage (sporocyst) in feces and can suffer from digestive problems (nausea, diarrhea, vomiting). Livestock become infected by ingesting food and water contaminated with sporocysts. ARS scientists now report another new species of Sarcocystis in cattle, Sarcocystis rommeli with an unknown life cycle. A search for the reservoir continues. These findings are of public and professional interest.
Technical Abstract: Cattle (Bos taurus) are intermediate hosts for three named species of Sarcocystis, S. cruzi, S. hirsuta, and S. hominis. Recently, a fourth species was identified and named S. sinensis. However, S. sinensis originally named a species of Sarcocystis in water buffalo (Bubalus bubalis) in China. Based on unverifiable evidence, it was suggested that the same parasite infects cattle. In addition, S. sinensis was recently declared as nomen nudum because its naming violated the rules of International Code of Zoological Nomenclature. Thus, the fourth species using cattle as an intermediate host does not have a valid name. Here, we propose a new name, Sarcocystis rommeli for the S. sinensis-like parasite from cattle in Argentina, and differentiate it ultrastructurally from S. hominis sarcocysts from experimentally infected cattle. Sarcocystis rommeli sarcocysts were microscopic with a 5-µm-thick wall with slender villar protrusions (Vp); the Vp were up to 5 µm long, up to 0.5 µm wide, and of uneven thickness, often bent at an angle. The ground substance layer (Gs) was up to 0.8 µm thick and smooth. Vesicular structures were seen at the base of the Vp. The bradyzoites were 10-12 µm long. Sarcocystis hominis sarcocysts had Vp that were often upright, up to 7.5 µm long, and up to 1.8 µm wide; the Gs was up to 2 µm thick and without vesicles. Its sarcocyst wall was up to 5.6 µm thick, the vp were bent at an angle, up to 5.8 µm long, the Gs was up to 2 µm thick, but without vesicles seen in S. rommeli. Beef containing sarcocysts of S. rommeli was not orally infectious for two human volunteers and a red fox (Vulpes vulpes). The Sarcocystis described here is molecularly different from S. cruzi, S. hirsuta, and S. hominis based on 18S rRNA and cox1 gene sequences.