Molecular and Microscopic Identification of Sarcocystis spp. in the Intestines of the Tawny Owl (Strix aluco) in Lithuania

The role of birds of the Strigiformes order in the transmission of globally distributed Sarcocystis parasites remains insufficiently studied. In the present work we aimed to evaluate the diversity of Sarcocystis species in the intestines of 22 naturally infected Tawny Owls (Strix aluco) sampled in Lithuania. The Sarcocystis infection was established using combined light microscopy and DNA sequence analysis. Samples were analyzed using Sarcocystis-genus and species-specific primers in nested PCR followed by Sanger sequencing. Sporocysts of Sarcocystis spp. were detected in 45.5% of samples, while 77.3% of samples were positive by molecular methods. Comparison of 28S rRNA and ITS1 sequences obtained and phylogenetic analyses indicated the presence of eight Sarcocystis taxa: S. halieti, S. kutkienae, S. turdusi, and Sarcocystis sp. ex Corvus corax, associated with birds, and S. funereus, S. glareoli, Sarcocystis sp. LT24Sa1, and Sarcocystis sp. LT24Sa11, associated with small mammals. Our results supplement previous findings that some Sarcocystis species can be transmitted by birds of three orders: Accipitriformes, Falconiformes, and Strigiformes. Overall, the low burden of sporocysts and predominance of single-species infections (63.6%) suggest that Tawny Owls transmit a limited number of Sarcocystis species associated with small mammals and birds.