Parasitology and Animal Diseases Department, Veterinary Research Division, National Research Centre, 33 El Buhouth St. (former El-Tahrir St.), Dokki, P.O. 12622, Giza, Egypt.
Department of Pathology and Clinical Pathology, Faculty of Veterinary Medicine, KafrElsheikh University, Kafr El-Sheikh, 33516, Egypt.
Parasitol Res. 2021 Feb;120(2):637-654. doi: 10.1007/s00436-020-07002-w. Epub 2021 Jan 18.
In a survey study on the macroscopic species of Sarcocystis infecting domestic sheep (Ovis aries) and cattle (Bos taurus) in Egypt, the macrosarcocysts of Sarcocystis gigantea and Sarcocystis medusiformis were detected in the carcasses of 33 domestic sheep out of a total of 250 (13.20%), whereas Sarcocystis hirsuta macrosarcocysts were found in 17 out of 150 cattle (11.33%) slaughtered at the municipal abattoirs of two different provinces in Egypt. The sarcocysts of each species were thoroughly described morphologically through gross inspection, histopathologic and transmission electron microscopic (TEM) examination. By TEM, S. gigantea primary cyst wall was 6-7.5 μm thick and had irregular highly branched cauliflower-like villar protrusions (VP).The VP contained microtubules (mt) and multiple electron dense granules (edg) that were dispersed inside the cores of the branched VP. Besides, the parasitophorous vacuolar membrane (PVM) had minute blister-like invaginations all over the entire surface of the sarcocyst. S. medusiformis cyst had a thin sarcocyst wall (~2 μm thick) as compared to that of S. gigantea. The cyst wall had trapezoidal or nearly pyramidal VP that were surrounded by thick PVM in addition to a ground substance GS that contained electron-dense fine particles. S. hirsuta sarcocyst wall was 7-9 μm thick and possessed rhomboid-shaped VP that contained microtubules (mt) and electron-dense granules (edg) of variable sizes. The edg were arranged in rows and running parallel to the longitudinal axis of the protrusions. The VP had characteristic narrow neck-like constrictions at their bases, dilated middle portions, and tapered distal ends. The detected macrosarcocysts were eventually confirmed by molecular characterization on the levels of 18S rRNA, 28S rRNA, and Cox1 sequences. Phylogenetic analyses based on the sequences of the 18S rRNA and Cox1 genetic markers gave rise to robust associations of the currently identified isolates of S. gigantea, S. medusiformis, and S. hirsuta within a major clade of Sarcocystis species with felines as presumed or known definitive hosts.
在一项针对埃及家养绵羊（Ovis aries）和牛（Bos taurus）中感染的肉孢子虫宏观种的调查研究中，从 250 只绵羊中检测到了巨肉孢子虫（Sarcocystis gigantea）和肉孢子虫（Sarcocystis medusiformis）的巨肉孢子虫，而从埃及两个不同省份的市屠宰场屠宰的 150 头牛中发现了 17 头牛有毛肉孢子虫（Sarcocystis hirsuta）巨肉孢子虫。通过肉眼检查、组织病理学和透射电子显微镜（TEM）检查，对每种肉孢子虫的肉孢子虫进行了彻底的形态描述。通过 TEM，巨肉孢子虫的初级囊壁厚 6-7.5μm，具有不规则的高度分支的菜花状绒毛状突起（VP）。VP 包含微管（mt）和多个电子致密颗粒（edg），这些颗粒分散在分支 VP 的核心内。此外，寄生泡膜（PVM）在肉孢子虫的整个表面都有微小的泡状内陷。与巨肉孢子虫相比，肉孢子虫的囊壁较薄（约 2μm 厚）。囊壁周围有厚的 PVM，VP 呈梯形或近乎金字塔形，此外还有包含电子致密细颗粒的基质 GS。肉孢子虫的囊壁厚 7-9μm，具有菱形 VP，其中包含微管（mt）和大小不等的电子致密颗粒（edg）。edg 排列成行，与突起的纵轴平行。VP 在其基部具有特征性的狭窄颈状收缩，中部扩张，远端变细。通过 18S rRNA、28S rRNA 和 Cox1 序列的分子特征最终证实了检测到的巨肉孢子虫。基于 18S rRNA 和 Cox1 遗传标记序列的系统发育分析，目前鉴定的巨肉孢子虫、肉孢子虫和毛肉孢子虫分离株与猫科动物作为假定或已知的终末宿主的肉孢子虫种形成了一个主要分支。
