1. Laboratory of Microbiology, School of Veterinary Medicine, Azabu University, Kanagawa, Japan
2. Laboratory of Veterinary Microbiology, Graduate School of Veterinary Science, Osaka Prefecture University, Osaka, Japan
3. Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan
4. Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, Kanagawa, Japan