1. Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Rua Prof. Cid dos Santos 1300‐477, Lisboa, Portugal
2. Department of Veterinary Pathology, Armed Forces Institute of Pathology, Washington D.C. 20306‐6000, USA
3. Department of Biomedical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA