1. Section of Arctic Veterinary Medicine (SAV), Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 6204, NO-9292 Tromsø, Norway; Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, SE-751 89 Uppsala, Sweden; Finnish Food Safety Authority Evira, Oulu Research Unit (FINPAR), P.O. Box 517, FIN-90101 Oulu, Finland; and Finnish Game and Fisheries Research Institute, Reindeer Research Station, FIN-99910...