Morphological and Molecular Description of Sarcocystis meriones n. sp. from the Libyan Jird (Meriones libycus) in Kuwait.

Sarcocystis is a genus of heteroxenous, globally distributed coccidian parasites. Limited research has been conducted on the natural infection of Sarcocystis in rodents in the Middle East. In this study, the Libyan jird (Meriones libycus) was identified as the natural intermediate host of the new species Sarcocystis meriones, based on morphological and molecular data. Microscopic sarcocysts were detected in the thigh muscles of 8.5% (4/47) of Libyan jirds captured from a semi-desert area in Amghara, Eastern Kuwait. Under the light microscope, sarcocysts were filamentous with blunt ends and thin walls, measuring 1550 × 89 µm. Transmission electron microscopy analysis showed the densely packed protrusions measure 1.2 × 0.5 µm and resemble thuja or a cylinder and having lateral microvilli, while the ground substance layer was 0.5-0.6 µm thick and type 22-like. Based on four genetic loci (18S rRNA, 28S rRNA, ITS1, and cox1), S. meriones was genetically most similar to S. myodes and S. ratti, infecting voles and mice of the genus Apodemus and black rats (Rattus rattus), respectively. Phylogenetic results suggest predatory mammals as potential definitive hosts of S. meriones. Further studies are needed to reveal host specificity, geographical distribution, and the impact of the parasite on the host's health of the newly described Sarcocystis species.