Microscopic and Molecular Detection of Sarcocystis cruzi (Apicomplexa: Sarcocystidae) in the Heart Muscle of Cattle

Background: Sarcocystis is a genus of coccidian protozoa that at least seven species of it can parasitize cattle. The global prevalence of Sarcocystis is close to 100% in adult cattle. The main aim of this study was to identify the infection rate of Sarcocystis spp. in heart of cattle in Tehran, Iran by microscopy and PCR-RFLP methods. 
Methods: Totally, 100 bovine heart samples were collected from the main slaughterhouse of Shahriar, Meysam slaughterhouse, west of Tehran in 2016. At first, heart samples were completely examined for the presence of sarcocystic macrocysts. Then, for microscopic examination, 50 g of each heart was digested in sterile condition using pepsin acid digestion method. Then, the species of the parasite were detected by PCR-RFLP technique and sequencing. 
Results: Overall, 97 of 100 of the heart muscle samples were infected with Sarcocystis. All the samples were detected as S. cruzi through similar patterns in PCR-RFLP. 
Conclusion: S. cruzi is the most common species in the heart of cattle slaughtered in Shahriar.