الفهرس 
Material and MethodsOnly 14 pages are availabe for public view
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Abstract
Sarcocystis species represent one of the mostly prevalent protozoon parasites of livestock animals. Few reports involved the infection of the Egyptian water buffaloes with these protozoa. Therefore, this study was conducted in order to investigate the prevalence and distribution patterns of different Sarcocystis species infecting water buffaloes slaughtered at Dakahlia Province, Egypt as well as to create a confirmative comparative ultrastructural morphological studies on different Sarcocystis species using the transmission electron microscopy. A total number of 550 slaughtered water buffaloes at Mansoura abattoir, Dakahlia Province, were examined at the period between July 2009 and June 2010. Detection of macroscopic sarcocysts was done by visual inspection of the muscular tissues (esophagus, heart, tongue, diaphragm and throat muscles), whereas muscle squash technique was used for the detection of microscopic cysts. Histopathology and transmission electron microscopy were then done for the positive Sarcocystis infected specimens. Examination of the collected muscle specimens revealed that 375 (68.18%) out of 550 slaughtered water buffaloes were infected with different Sarcocystis species which may be due to the abundance of final hosts (dogs and cats) which live in close relation with buffalo herds. It is found that the macroscopic species (63.45%) were more common than microscopic ones (48.36%) and this evoke the significant role of felines in transmission of Sarcocystis species more than canines. Based upon size, shape and location of the sarcocyst as well as the structure of the cyst wall, four morphologically distinct Sarcocystis species were found in Egyptian water buffaloes. Two of them had macroscopically visible sarcocysts: S. fusiformis (58.72%) and S. buffalonis (8.72%). The other two species were microscopic cysts forming species: S. levinei (47.45%) and S. dubeyi (3.45%). Concerning distribution patterns of Sarcocystis infection in different tissues, it was noted that the esophagus was the most infected tissue with all the four species of Sarcocystis, while S. buffalonis was not found in heart or tongue. S. levinei was the only species found in the heart, furthermore, S. dubeyi was detected in esophagus and throat muscles, but never found in Tongue, heart or diaphragm. The differentiation between the macroscopically visible species was easily done by their gross appearance. S. fusiformis was milky white, spindle-shaped cysts, sometimes embedded deeply in host tissues and measured 4-35 X 1-8 mm, while S. buffalonis cyst (2-10 X 0.5-1.0 mm) appeared as white threads under the connective tissue layer of the muscular tissue and sometimes twisted due to the postmortem contractions of the underlying muscles. The wall of S. fusiformis was thin (1-2 µm) and had highly branched villar cauliflower-like villar protrusions, while that of S. buffalonis was thick (3.5-7 µm), striated and had palisade-like villar protrusions with constricted base , laterally expanded mid region and tapered tips, and bending on the sarcocyst surface by 45◦. The present work described for the first time the ultrastructure of S. buffalonis cysts recovered from the Egyptian water buffaloes (Bubalus bubalis). Dealing with the microscopic cyst forming species: S. levinei and S. dubeyi, S. levinei cyst was narrow spindle, oval or round shaped and reaches up to 0.9 X 0.2 mm in size. Their cyst wall appeared to be very thin (0.6-1 µm) and smooth with long filamentous villar protrusions bending 90◦ on the cyst surface and had dome-shaped base, finger like middle part and tapered distal end. Moreover, S. dubeyi cysts were spindle shaped, sometimes with undulating edges and measured up to 0.7 x 0.2 mm. their striated cyst wall was thick (4.5-8.5 µm), and emanating cylindrical villar protrusions with uniform length and width and flattened tips. It could be concluded that the Egyptian water buffaloes are found harboring four species of Sarcocystis infection. Namely: S. fusiformis, S. buffalonis, S. levinei and S. dubeyi. The important goal of this study is achieved by giving a confirmative comparative ultrastructure using the transmission electron microscopy of the four detected Sarcocystis species including S. buffalonis for the first time in Egypt.