1. Bureau of Epidemiology, Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand.
2. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
3. Department of Virology, Armed Forces Institute of Medical Sciences, Bangkok, Thailand.
4. Viral Disease Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland.
5. Nan Provincial Livestock Office, Department of Livestock Development, Ministry of Agriculture and Cooperatives, Nan Province, Thailand.
6. Department of International Health & Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
7. Department of Food-Animal Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand.