1. Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan
2. Virology Department, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi, Vietnam
3. Food and Agriculture Organization, 3 Nguyen Gia Thieu, Hoan Kiem, Hanoi, Vietnam
4. ACT Co., Ltd., 21-5, Minami-4, Nishi-21, Obihiro, Hokkaido 080-2471, Japan