1. Department of Veterinary Diagnostic and Production Animal Medicine; Iowa State University College of Veterinary Medicine; Ames IA USA
2. Centre for Public Health and Zoonoses; University of Guelph; Guelph ON Canada
3. Department of Population Medicine; Ontario Veterinary College; University of Guelph; Guelph ON Canada
4. Department of Statistics; Iowa State University College of Liberal Arts and Sciences; Ames IA USA