Molecular determination of abundance of infection with Sarcocystis species in slaughtered sheep of Urmia, Iran

Sarcocystis is one of the most prevalent parasites of domestic ruminants worldwide. This study was aimed to determine prevalence of Sarcocystis infection and molecular discrimination of Sarcocystis gigantea and Sarcocystis medusiformis infecting domestic sheep. Tissue samples from 638 sheep slaughtered at Urmia abattoir were randomly collected from February 2011 to January 2012. Genomic DNA extraction and polymerase chain reaction (PCR) was performed to amplify a 964 bp fragment of nuclear 18S rRNA gene. The PCR products were subjected to digestion with endonuclease MboII and/or MvaI for discriminating S. medusiformis and S. gigantea. Results indicated that the overall prevalence of Sarcocystis unspecified species was 36.83% (235/638) in which male (7.63%, 38/498) and female (35.00%, 49/140) sheep over 4 years-old had the highest prevalence. There was no significant difference between prevalence of macrosarcocysts and sex. Two macrosarcocysts forms were found as fat (27.90%, 178/638) and thin (8.93%, 57/638) in striated muscles. There was significant difference between frequency of macrosarcocysts and body distribution. Mixed infection with both fat and thin macrosarcocysts was also found in 11.13% (71/638) of infected sheep. There was no significant difference regarding the prevalence of mixed infection in both age classes. The PCR-RFLP patterns showed that fat sarcocysts were S. gigantea (29.31%, 187/638) and thin sarcocysts were S. medusiformis (7.52%, 48/638). It was concluded that ovine Sarcocystis infection was prevalent in Urmia and a combination of conventional methods and molecular study for sheep sarcocysts could be informative.