1. Center for Infectious Disease Epidemiology and Prevention Research, Tokyo University of Agriculture and Technology, Tokyo, Japan
2. Kurayoshi Livestock Hygiene Service Center, Tottori, Japan
3. Japanese Animal Hospital Association, Tokyo, Japan
4. Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, USA
5. Laboratory of Infectious Diseases, Department of Veterinary Medicine, Faculty of Veterinary Medicine, Azabu University, Kanagawa, Japan