1. Cornell University College of Veterinary Medicine, Upper Tower Road, Ithaca, NY 14853, USA
2. *University of Minnesota College of Veterinary Medicine, 1365 Gortner Avenue, St Paul, MN 55108, USA
3. †University of Wyoming Diagnostic Laboratory, Jackson Hole, WY, USA
4. ‡Raven Veterinary Clinic, 1684 Palomino Drive, North Pole, AK 99705, USA
5. §CUniversity of Fairbanks, Institute of Arctic Biology, PO Box 757000, Fairbanks, AK 99775, USA
6. ¶University of Pennsylvania College of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA