Prevalence and molecular assessment of Sarcocystis infection in livestock in northeast Iran.

Sarcocystis is an intracellular parasite of the apicomplexa phylum. More than one hundred species of Sarcocystis can infect wildlife and livestock animals. Samples of the liver, heart, muscle and diaphragm were collected from sheep, goats and cattle in Gonabad, northeast Iran and subjected to macroscopic, microscopic, tissue digestion, sequencing and phylogenetic analyses of 18S-rRNA region. Tissue sections stained with hematoxylin and eosin were also provided for surveying sarcocysts in the samples. Tissue digestion showed that all animal samples (100%) were infected with Sarcocystis bradyzoites. Phylogenetic analysis indicated that out of 50% of sheep genotypes belonged to S. tenella, and 20% to S. moulei and S. arieticanis. Moreover, three samples of macroscopic specimens of sheep were identified as S. gigantea, 100% of cattle isolates infected with S. cruzi, 80% of goat isolates belonged to S. capracanis and one macroscopic specimen of goat (20%) identified as S. moulei. Sarcocystis infection is highly prevalent in livestock in northeast Iran, where a variety of Sarcocystis species are unequivocally circulating in the region.