1. Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand and Henry M. Jackson Foundation, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
2. Royal Thai Army Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand and Department of Pediatrics, Pramongkuklao Hospital School of Medicine, Bangkok Thailand
3. Royal Thai Army Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
4. Henry M. Jackson Foundation, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
5. Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
6. Faculty of Medicine, Chiang Mai University, Thailand
7. Northern Drug Dependence Treatment Center, Chiang Mai, Thailand
8. Henry M. Jackson Foundation, Rockville, Maryland 20850
9. U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
10. Henry M. Jackson Foundation, Rockville, Maryland 20850 and Walter Reed Army Institute of Research, Rockville, Maryland 20850
11. Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand
12. Henry M. Jackson Foundation, Rockville, Maryland 20850 and Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205