1. Department of PathologyUniversity of Washington, Seattle, WA, USA
2. Department of BiologyUniversity of Alabama at Birmingham, Birmingham, AL, USA
3. College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
4. Veterinary EpidemiologyEconomics and Public Health, The Royal Veterinary College, Hatfield, UK
5. Department of BiologyUniversity of Washington, Seattle, WA, USA