Molecular characterization of five Sarcocystis species in red deer ( Cervus elaphus), including Sarcocystis hjorti n. sp., reveals that these species are not intermediate host specific

Abstract

Muscle tissue from 37 red deer from Norway was examined for sarcocysts. Sarcocysts from 2 reindeer were obtained for comparative studies. Cysts were excised and morphologically classified by light microscopy, scanning electron microscopy, and DNA sequence analysis. Five Sarcocystis species, Sarcocystis hjorti n. sp., Sarcocystis hardangeri, Sarcocystis ovalis, Sarcocystis rangiferi, and Sarcocystis tarandi, were found. All 5 species have previously been identified from either reindeer or moose by their sarcocyst morphology and/or ssu rRNA gene sequence. S. hjorti was the most prevalent species. Multiple variants of the ssu rRNA gene and the first internal transcribed spacer were found in S. rangiferi and S. tarandi from both red deer and reindeer. Phylogenetic analyses indicated that S. tarandi occurs in both red deer and reindeer, but it could not be clearly demonstrated whether the sequence variation within S. rangiferi between hosts was due to different paralogues or/and different species. DNA sequencing was necessary for definitive species identification, since the hair-like protrusions on the cysts of S. hjorti were not always recognizable by light microscopy and since different cervids harbour Sarcocystis species with highly similar cyst morphology of which at least some are not intermediate host specific.