1. Department of Animal Environment and Health, Swedish University of Agricultural Sciences, PO Box 234, SE-532 23 Skara, Sweden
2. Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, PO Box 7054, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
3. Swedish Toxicology Sciences Research Center (Swetox), Forskargatan 20, SE-151 36 Södertälje, Sweden
4. Institute of Environmental Medicine, Karolinska Institute, PO Box 210, SE-171 77 Stockholm, Sweden