Ultrastructural and molecular characterization of Sarcocystis isolated from camel (Camelus dromedarius) in Iran

Sarcocystis cameli was first described in one-humped camels (Camelus dromedarius), and it is the only species which have so far reported in camels. Although more than 150 species of Sarcocystis were described in various animals, only a few data on camel Sarcocystis ultrastructure were published, and this report is the first for molecular information (DNA sequence and RLFP digestion pattern). The main objective of the present work is to characterize Sarcocystis isolated from camels by electron microscopy and PCR-RFLP methods. Muscle samples were taken from the fresh esophagus, diaphragm, skeletal muscles, and heart of one-humped camels (C. dromedarius) slaughtered in abattoirs of Tehran and Ghazvin provinces, Iran. The dissection and trypsin digestion techniques were applied for the detection of the cysts. The infected samples were fixed in glutaraldehyde and/or frozen at -20°C until use for ultrastructural and molecular studies, respectively. The ultrastructural and molecular studies were carried out contemporaneously. The 18S rRNA gene of the parasites was amplified by PCR. The PCR products were cloned into a pTZ57R/T and sequenced. In addition, the PCR products were digested separately with each of the four restriction enzymes for RFLP. Our results indicated that only microcysts were observed in muscle samples. The microcysts were white, elongated, spindled, and a few spiral-shaped, with mean size 260 × 75 μm which are identical with S. cameli. The ultrastructure of microcyst wall had many non-branched finger-like protrusions irregularly folded. There was a 600-bp specific band amplified after PCR with specific primers. The molecular data for camel Sarcocystis is reported for the first time in Iran and the world.