1. Department of Pathobiology, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand
2. Veterinary Associates, Hastings, New Zealand
3. Department of Pathobiology and Diagnostic Investigation/Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
4. New Zealand Veterinary Pathology Ltd, Palmerston North, New Zealand