1. Norwegian Veterinary Institute, P.O. Box 64, NO-1431 Ås, Norway
2. Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO-7485 Trondheim, Norway
3. Finnish Food Authority, Helsinki, Finland
4. National Veterinary Institute (SVA), Uppsala, Sweden
5. Natural Resources Institute Finland (LUKE), Yliopistokatu 6, FI-80100 Joensuu, Finland
6. Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden
7. Present address: Kontali, Fred Olsens gate 1, NO-0152 Oslo, Norway
8. Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway