cyst wall ultrastructure of sarcocystis spp. isolated from slaughtered sheep in qazvin, iran

sarcocystis is a coccidia protozoan develops obligatory in two hosts consisting of the herbivores as an intermediate host (prey) and the carnivores as a host (predator). depend on species, the size of cysts and structure of cyst wall in intermediate hosts are different. the ultrastructure of sarcocystis cysts (sarcocysts) could be a good indication for diagnosis of the parasite species. in the present study the ultrastructure of macroscopic sarcocystis isolated from slaughtered sheep in qazvin ziaran slaughterhouse were investigated. the macroscopic cysts isolated from sheep muscles were fixed in 3% glutaraldehyde following washing with buffer phosphate. ultrastructural charecters of the cysts were studied using transmission electron microscope (tem400). the macroscopic cysts were located within muscles and were limited by a primary cyst wall (pcw). according to ultrastructural characters of pcw, two species of sarcocystis, s. gigantea and s.medusiformis were identified as macroscopic cyst in sheep. the primary cyst wall of s.gigantea having cauliflower–like protrusions at 12000× magnification and s. medusiformis having villous like protrusions at 7500× magnification.