title: Corvid birds (Corvidae) act as definitive hosts for Sarcocystis ovalis in moose (Alces alces).
abstract: Epidemiological data and a unique phylogenetic position had suggested that Sarcocystis ovalis in moose and red deer might use a definitive host other than canids, felids, or humans. Corvid birds and rats were therefore evaluated as potential definitive hosts for this species in a small pilot study. Four laboratory rats were each inoculated with 10 or 25 sarcocysts of S. ovalis isolated from moose, but no Sarcocystis oocysts were detected in their intestinal mucosa upon euthanasia 2 to 3 weeks later. At a site where large flocks of corvid birds (hooded crows, ravens and European magpies) fed on remnants of moose carcasses during the hunting period in October, fresh bird droppings were collected on the ground and examined microscopically and by molecular methods. By microscopy, a small number of typical Sarcocystis sporocysts, measuring 12.8 × 8.4 μm, were found in the faecal samples. These sporocysts were identified as belonging to S. ovalis by a polymerase chain reaction assay using specific primer pairs targeting the ssu rRNA gene, followed by sequence analysis. The intestinal contents of a crow and two magpies shot near the dumping site were also examined. Sarcocystis oocysts (16.1 × 12.4 μm) and free sporocysts (12.5 × 7.9 μm) were found in the intestinal mucosa/contents of one magpie (Pica pica). These oocysts/sporocysts were also found to belong to S. ovalis by the same molecular assay. This is the first report of corvid birds acting as definitive hosts for a species of Sarcocystis.
authors.affiliation: Department of Food Safety and Infection Biology, Section of Microbiology, Immunology and Parasitology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., 0033, Oslo, Norway. Bjorn.Gjerde@nvh.no
authors.forename: Bjørn
authors.initials: B
authors.lastname: Gjerde
authors.forename: Stina S
authors.initials: SS
authors.lastname: Dahlgren
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000469:parasitology*; D001717:Birds; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005243:Feces / Q000469:parasitology; D020459:Genes, rRNA; D008853:Microscopy; D008969:Molecular Sequence Data; D046109:Passeriformes / Q000469:parasitology*; D016133:Polymerase Chain Reaction; D016053:RNA, Protozoan / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D051381:Rats; D012376:Rodent Diseases / Q000469:parasitology; D012418:Ruminants / Q000469:parasitology*; D012522:Sarcocystis / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D012523:Sarcocystosis / Q000469:parasitology / Q000662:veterinary*; D017422:Sequence Analysis, DNA
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S