Molecular characterization of fiveSarcocystisspecies in red deer (Cervus elaphus), includingSarcocystis hjortin. sp., reveals that these species are not intermediate host specific

Abstract

SUMMARYMuscle 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. FiveSarcocystisspecies,Sarcocystis hjortin. sp.,Sarcocystis hardangeri, Sarcocystis ovalis, Sarcocystis rangiferi, andSarcocystis 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. hjortiwas the most prevalent species. Multiple variants of the ssu rRNA gene and the first internal transcribed spacer were found inS. rangiferiandS. tarandifrom both red deer and reindeer. Phylogenetic analyses indicated thatS. tarandioccurs in both red deer and reindeer, but it could not be clearly demonstrated whether the sequence variation withinS. rangiferibetween 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 ofS. hjortiwere not always recognizable by light microscopy and since different cervids harbourSarcocystisspecies with highly similar cyst morphology of which at least some are not intermediate host specific.