first molecular identification of sarcocystis ovicanis (protozoa, apicomplexa) in the brain of sheep in iran.

background: the objective of the present study was to survey the presence of sarcocystis in sheep's brain in north khorasan province. methods: in general, 80 samples of sheep's brain were collected from slaugh-tered sheep in slaughterhouses of north khorasan province. tissue digestion method was used for observing bradyzoites in tissues. histopathological pro-cessing tracing sarcocystis and ensuing structural change in the brain tissue were conducted. pcr analysis was conducted on all the brain samples. sequencing was done for one pcr product. genotype was identified by blast search and homology analysis. result: sarcocystis spp. was found in one of the brain samples (1.25%) using tis-sue digestion method. the presence of bradyzoite was also confirmed in the pre-pared histopathological sections. pcr analysis was positive in one of samples. genotyping of one sample proved that sarcocystis species was sarcocystis ovicanis and the nucleotide sequence of this parasite was deposited in the genbank data-base under accession number no.kf489431. conclusion: sarcocystis ovicanis can involve brain tissue of sheep and conse-quently causes clinical symptoms.