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Title: Ultrastructure of Sarcocystis bertrami sarcocysts from naturally infected donkey (Equus asinus) from Egypt

item Dubey, Jitender
item VAN WILPE, EMA - University Of Pretoria
item HILALI, MOUSSAD - Cairo University

Submitted to: Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2015
Publication Date: 11/2/2015
Citation: Dubey, J.P., Van Wilpe, E., Hilali, M. 2015. Ultrastructure of Sarcocystis bertrami sarcocysts from naturally infected donkey (Equus asinus) from Egypt. Parasitology. 143(01):18-23.

Interpretive Summary: Sarcocystis neurona is a single celled parasite previously misidentified as Toxoplasma gondii. It causes a fatal illness in horses and several other species of animals. The clinical syndrome was called “Equine Protozoal Myeloencephalitis” before ARS researchers in collaboration with scientists from several universities identified, isolated it, and named it Sarcocystis neurona in 1991. The host range for S. neurona keeps expanding and this parasite is now recognized as a major cause of death in sea otters. There is considerable confusion regarding the species of Sarcocystis in equids, including donkeys. The popularity of donkeys as companion animal is increasing. In the present paper the authors described in detail a species of Sarcocystis in donkeys, as distinct from Sarcocystis neurona. This paper should be of interest to biologists, parasitologists, and veterinarians.

Technical Abstract: There is considerable confusion concerning Sarcocystis species in equids. Little is known of Sarcocystis infections in donkeys (Equus asinus). Here we describe the structure of Sarcocystis bertrami-like from the donkey by light and transmission electron microscopy (LM, TEM). Nineteen sarcocysts from the tongue of a donkey from Egypt were studied both by LM and TEM. By LM, all sarcocysts had variably shaped and sized projections on the sarcocyst walls, giving it a thin-walled to thick-walled appearance, depending on individual sarcocyst and plane of section. By TEM, sarcocysts walls had villar protrusions (vp) of type 11. The sarcocyst wall had conical to slender vp, up to 6 µm long and 1µm wide; the vp were folded over the sarcocyst wall. The total thickness of the sarcocyst wall with ground substance layer (gs) was 1-3 µm. The vp had microtubules that originated deeper in the gs and continued up to the tip. The apical part of the vp had electron dense granules. The microtubules (mt) were configured in to 3 types: a tuft of electron dense mt1 extending the entire length of the vp with a tuft of medium electron dense mt2 appearing in parallel, and fine mt3 present only in the villar tips. The gs was mainly smooth with few indistinct granules. All sarcocysts were mature and contained metrocytes and bradyzoites. Bradyzoites were approximately 11-15 x 2-3 µm in size with typical organelles. Key words: Sarcocystis bertrami, donkey (Equus asinus), transmission electron microscopy