The red fox (Vulpes vulpes) and the arctic fox (Vulpes lagopus) are definitive hosts ofSarcocystis alcesandSarcocystis hjortifrom moose (Alces alces)

Abstract

SUMMARYThe aim of this study was to determine whether foxes might act as definitive hosts ofSarcocystis alcesin moose. In 2 experiments, 6 silver foxes (Vulpes vulpes) and 6 blue foxes (Vulpes lagopus) were fed muscle tissue from moose containing numerous sarcocysts ofS. alces, and euthanased 7–28 days post-infection (p.i.). Intestinal mucosal scrapings and faecal samples were screened microscopically forSarcocystisoocysts/sporocysts, which were identified to species by means of species-specific primers and sequence analysis targeting the ssu rRNA gene. All foxes in both experiments became infected withSarcocystis; the oocysts were fully sporulated by 14 days p.i., containing sporocysts measuring 14–15×10 μm. Molecular identification revealed that the oocysts/sporocysts belonged to 2 species,S. alcesandSarcocystis hjorti, although sarcocysts ofS. hjortiwere only identified in moose subsequent to the infection of foxes. In the first experiment, all 8 foxes also became infected with aHammondiasp. derived from moose, shedding unsporulated, subspherical oocysts, measuring 10–12 μm in diameter, from 6–7 days p.i. onwards. The study proved that canids (the red fox and arctic fox) are definitive hosts forS. alcesandS. hjorti, as had been inferred from the phylogenetic position of these species.