Morphological and molecular identification of Sarcocystis sp. from the Temminck's stint, Calidris temminckii (Leisler) (Charadriiformes: Scolopacidae), for the first time in Egypt.

Scarce literature on sarcocystosis in wading and migratory birds in Egypt is available. Meanwhile, studies on sarcocystosis in Charadriiformes are lacking. The present study aimed to investigate the occurrence of sacrcocysts in muscles of the Temminck's stints, Calidris temminckii (Leisler) (Charadriiformes: Scolopacidae) in Qena province, Upper Egypt. Muscle specimens from 35 Temminck's stints were parasitologically examined, using light microscopy, transmission electron microscopy and molecular tools including conventional PCR and phylogenetic analysis using both 18S rRNA and 28S rRNA genetic loci, during the period from September 2018 to December 2022. In Calidris temminckii (13/35; 37.14%), sarcocysts were thread-like. Ultrastructurally, the thick cyst wall contained finger-like protrusions of variable sizes with underlining by a clear ground substance with internally located bradyzoites and metrocytes. Generally, this is the first report denoting the occurrence of Sarcocystis sp. from C. temminckii and, in particular, Egypt. Phylogenetic analysis proved that Sarcocystis atraii El-Morsey, El-Seify, Desouky, Abdel-Aziz, El-Dakhly, Kasem, Abdo, Haridy, Sakai and Yanai, 2015 is the most genetically closely related to our specimens, however, with different ultrastructural morphology. Both S. atraii and our specimens exhibited a host ecology-based convergence pattern with Sarcocystis rileyi ( Stiles 1893) Minchin, 1903. Future traditional and molecular studies are required to identify both macroscopic and microscopic sarcocysts in domestic and wild birds in Egypt.