Protozoan Parasites of Sarcocystis spp. in Rodents from Commercial Orchards

SIMPLE SUMMARY: Small mammals not only play an important role in ecosystems, but they also can transmit a wide range of pathogens to humans and domestic animals. The data on protozoan Sarcocystis parasites in orchard-dwelling small mammals are still scarce. Members of the genus Sarcocystis form sarcocysts in the muscles of intermediate hosts and develop sporocysts in the intestines of definitive hosts. In the present study, 679 muscle samples of small mammals, collected in commercial orchards and berry plantations in Lithuania, were screened for Sarcocystis parasites via DNA analysis. The prevalence of Sarcocystis spp. was low as only nine pooled muscle samples were found to contain the parasites examined. Four species were identified in the examined small mammals, including two potentially new Sarcocystis species that were detected in the muscles of voles. The phylogenetic results suggested that birds and mammals are the definitive hosts of the Sarcocystis spp. identified in the current study. ABSTRACT: Small mammals are an important group of wildlife that can transmit pathogens to humans and animals. There is a lack of comprehensive studies on the protozoan parasites of the genus Sarcocystis in agricultural areas. The aim of the current research was to evaluate the prevalence of Sarcocystis spp., and to identify the parasite species found in the skeletal muscles of rodents and insectivores from commercial orchards. A total of 679 muscle samples from small mammals, mainly rodents (n = 674), belonging to eight species were examined. Muscle samples were pooled into groups, then digested, and the presence of the Sarcocystis species was confirmed by molecular methods. The examined parasites were determined in five rodent species, Apodemus agrarius, A. flavicollis, Clethrionomys glareolus, Microtus arvalis, and M. oeconomus. The prevalence of Sarcocystis spp. was low: 2.23% in voles and 0.79% in mice. Based on a sequence comparison of cox1 and 28S rDNA, four species were identified: S. myodes, Sarcocystis cf. strixi, Sarcocystis sp. Rod1, and Sarcocystis sp. Rod2. This is the first report of S. myodes in A. agrarius, A. flavicollis, and M. arvalis. The identified species were most closely related to Sarcocystis spp., and were transmitted by predatory mammals and birds. Future studies are needed to describe the species morphologically, as well as to define the host spectrum and to evaluate their possible pathogenicity.