1. Department of Veterinary Pathology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
2. University of Helsinki, Faculty of Medicine, Medicum, Department of Virology, Helsinki, Finland
3. Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
4. University of Helsinki, Faculty of Veterinary Medicine, Department of Veterinary Biosciences, Helsinki, Finland