Zoology Department, Faculty of Science, Cairo University, Egypt.
Vet Parasitol. 2011 Sep 27;181(2-4):75-82. doi: 10.1016/j.vetpar.2011.05.010. Epub 2011 May 19.
Cysts of Sarcocystis capracanis obtained from infected goats were examined to clarify the effect of the parasite on the host. Muscle tissues from fresh oesophagus, tongue, diaphragm and skeletal muscles of 680 goats were slaughtered in the main abattoir of Cairo, Egypt and they were examined microscopically for Sarcocystis infection for the first time in Egypt. 540 out of 680 (79.4%) of examined goats were found to be infected with Sarcocystis sp. The infection was recorded firstly by light microscopy as spindle shaped cysts embedded in the muscle tissues. The validity of this species as S. capracanis was confirmed by means of ultrastructural characteristics of the primary cyst wall which revealed the presence of thick-radially striated wall with finger like projections, underlined by a thick layer of ground substance enclosing the developing metrocytes and merozoites that usually contain nearly all the structures of the apical complex and fill the interior cavity of the cyst. The cyst cavity is divided by many septa extending from the ground substance and producing large number of chambers. An experimental infection using the highly infected muscles was carried out to determine the final host, which is dog. Smears of intestinal epithelium were taken to examine the endogenous stages (gamogony and sporogony) by means of light microscopy. These stages were mainly observed as to infect the lamina propria of the posterior third of the small intestine. Gamogony and zygote formation (fertilization) occurred 2-8 days post infection, while sporulation took place within the final host 13-15 days and sporocysts were passed within faeces of the infected puppies at that time. The prepatent period of S. capracanis was 12-15 days, while the patent period was extended to 37 days. In goats, infection with S. capracanis led to the loss of weight, anaemia, abortion and even death in cases of heavy infection. While bleeding, watery faeces filled with mucous on 5th and 8th day p.i. as well as intestinal lesions are the pathogenic effects occurred in puppies after experimental infection.
从感染的山羊中获得的 Sarcocystis capracanis 囊肿被检查，以阐明寄生虫对宿主的影响。在埃及开罗的主要屠宰场，首次对 680 只山羊的新鲜食道、舌、横膈膜和骨骼肌进行了屠宰，并对 Sarcocystis 感染进行了显微镜检查。在 680 只检查的山羊中，有 540 只（79.4%）被发现感染了 Sarcocystis sp. 这种感染首先通过光镜记录为嵌入肌肉组织中的纺锤形囊肿。通过初级囊壁的超微结构特征证实了该物种的有效性，初级囊壁显示出存在厚的放射状条纹壁，带有指状突起，由一层厚厚的基质包围，基质内包含发育中的原细胞和裂殖子，裂殖子通常包含顶复合物的几乎所有结构，并充满囊肿的内部腔室。囊腔被许多从基质延伸的隔膜分隔，产生大量腔室。使用高度感染的肌肉进行了实验感染，以确定最终宿主，即狗。通过光镜从肠上皮刮取涂片，检查内源性阶段（配子发生和孢子发生）。这些阶段主要观察到感染小肠后三分之一的固有层。配子发生和受精卵形成（受精）发生在感染后 2-8 天，而孢子发生发生在最终宿主中 13-15 天，此时感染的幼犬粪便中排出孢子囊。S. capracanis 的潜伏期为 12-15 天，而发病期延长至 37 天。在山羊中，感染 S. capracanis 会导致体重减轻、贫血、流产，甚至在严重感染的情况下死亡。在感染后 5 天和 8 天，幼犬出现出血、水样粪便，粪便中充满黏液以及肠道病变，这是实验感染后发生的致病性影响。
