|HILALI, MOUSSAD - Cairo University|
|VAN WILPE, EMA - University Of Pretoria|
|CALERO-BERNAL, RAFAEL - Non ARS Employee|
|VERMA, SHIV - Non ARS Employee|
|ABBAS, IBRAHIM - Mansoura University|
Submitted to: Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2015
Publication Date: 7/1/2015
Citation: Dubey, J.P., Hilali, M., Van Wilpe, E., Calero-Bernal, R., Verma, S., Abbas, I. 2015. A review of sarcocystosis in camels and redescription of Sarcocystis cameli and Sarcocystis ippeni sarcocysts from the one-humped camel (Camelus dromedarius). Parasitology. doi: 10.1017/S0031182015000852.
Interpretive Summary: Coccidian parasites in the phylum Apicomplexa include myriad parasites that are transmitted when a definitive host consumes the infected tissue of an intermediate host, or when an intermediate host consumes water or food contaminated with the feces of a definitive host. Toxoplasma gondii is an important zoonotic parasite that compromises food safety by infecting tissues of food animals and by contaminating produce. This parasite is difficult to distinguish from many similar parasites that cause no known risk to human health. Among these are parasites in the genus Sarcocystis known to cause encephalitis in a variety of mammalian and avian hosts. When species names are applied to organisms lacking meticulously described attributes and lacking voucher reference materials, imprecise scientific communication and incorrect diagnoses result. Here we redescribe 2 species of Sarcocystis in camels, to remove the existing confusion in literature. This paper should be of interest to biologists, parasitologists, and veterinarians.
Technical Abstract: There is considerable confusion concerning Sarcocystis species in camels. Five species: Sarcocystis cameli, S. ippeni, S. camelicanis, S. camelocanis, and S. miescheri were named with inadequate descriptions and no type specimens. Here, we review literature on sarcocystosis in camels worldwide and redescribe structure of S. cameli and S. ippeni sarcocysts by light and transmission electron microscopy (LM, TEM). Five sarcocysts from the esophagi of 2 camels (Camelus dromedarius) from Egypt were studied. By LM all sarcocysts were thin walled with barely visible projections on the cyst walls. By TEM, 2 structurally distinct sarcocysts were recognized by characteristic unique villar protrusions (vp) not found in sarcocysts from any other host. Sarcocysts of S. cameli had vp of type 9j. The sarcocyst wall had upright slender vp, up to 3.0 µm long and 0.5 µm wide; the total thickness of the sarcocyst wall with ground substance layer (gs) was 3.5 µm. On each vp there were rows of knob-like protrusions that appeared to be interconnected in a mesh-like structure. The vp had microtubules that originated at mid point of the gs and continued up to the tip; microtubules were smooth, without any granules or dense areas. Bradyzoites were approximately 14-15 x 3-4 µm in size with typical organelles. Sarcocystis ippeni sarcocysts had type 32 sarcocyst wall characterized by conical villar protrusions with an electron dense knob. The total thickness of the sarcocyst wall (from the base of gs to vp tip) was 2.3-3.0 µm. The vp were up to 1.2 µm wide at the base and 0.25 µm at the tip. Microtubules in vp originated at midpoint of gs and continued up to tip; microtubules were criss-crossed, smooth and without granules or dense areas. Bradyzoites were 12.0-13.5 x 2.0-3.0 µm in size. Sarcocystis camelicanis, S. camelocanis, and S. miescheri are considered invalid.