Comparative morphological studies on three Sarcocystis species in Sohag, Egypt.

Samples from the tongue, heart, oesophageal and skeletal muscles were collected from 100 cow and 100 buffalo from Sohag slaughterhouses. Macroscopic examination for sarcocysts was followed by microscopic ones on impression smears and compressed muscles. Histological sections and transmission electron microscope (TEM) studies were done on positive cases. Sarcocystis infection rate of cows were 84%. Two species of Sarcocystis were detected: 1- S. cruzi with a membrane provided with hair-like villar protrusions folded over the surface of the cyst. These protrusions were rod-like, round, oval or irregular in shape and were approximately parallel to the cyst surface. 2-S. hominis characterized by a cyst wall consisting of cylindrical finger-like villar protrusions and having microfilaments. The protrusions were perpendicular on the cyst surface with broad tips and contain microfilaments. Buffaloes' muscle samples revealed an infection rate of 28%. The macroscopic fusiform-shaped species only was detected (Sarcocystis fusiformis). The role of cyst wall ultrastructure and thickness were discussed regarding identification and pathogenicity.