ABSTRACT
Study on the prevalence of macroscopic and microscopic cysts of Sarcocystis in slaughtered cattle by direct inspection, impression smear and digestion method. Cross-sectional study. Two hundreds of cattle slaughtered at Shiraz slaughterhouse. Simple random sampling, determination of sex and age, direct inspection of esophagus, tongue and different muscles to find macroscopic cysts, sampling from tongue, heart, diaphragm and esophagus, preparing tissue smear and staining by Giemsa, digesting samples by PBS containing HC1 and pepsin, staining the precipitate by Giemsa, and examining the stained smear for bradyzoites. No macroscopic cyst was observed. All samples in digestion method and 99% of them in impression smear method were diagnosed to be infected by microscopic cysts. The sensitivity rate of impression smear method to diagnose the microscopic cysts was 72.0% in esophagus, 78.5% in diaphragm, 79.5% in tongue and 98.5% in heart. Sex and age had no effect on infection rate. There was no significant difference among infection rates of different organs.According to high infection rate of cattle with microscopic cyst, the identification of Sarcocystis spp and their prevalence rate is very important. S.cruzi causes Dalmeny disease in cattle and S.bovihominis causes intestinal sarcocystosis in humans. The latter is transmitted by consumption of infected beef. Avoiding consumption of under-cooked beef is highly advisable in infected areas which are world wide in distribution