Identification of Sarcocystis rileyi from the mallard duck (Anas platyrhynchos) in Europe: cyst morphology and results of DNA analysis

Macroscopic cysts of Sarcocystis in ducks were recorded in Europe, but they were not investigated in more detail. Results of light and electron microscopy as well as 18S rDNA, 28S rDNA and ITS-1 region sequences of Sarcocystis macrocysts isolated from naturally infected mallard duck (Anas platyrhynchos) from Lithuania are presented in this paper. According to ultrastructure results, macrocysts examined corresponds to S. rileyi. Phylogenetic investigation showed S. rileyi to be the most closely related to two unnamed Sarcocystis species from anseriforms and to the S. mucosa. This is the first well-documented case of S. rileyi in Europe.