Affiliation: | Mahidol University, Bangkok, Thailand (P. Puthavathana, K. Sangsiriwut, A. Korkusol, P. Pooruk, P. Auewarakul); Ministry of Public Health, Nonthaburi, Thailand (C. Pittayawanganon, D. Sutdan, R. Kitphati, P. Sawanpanyalert, K. Ungchusak);Ministry of Health, Vientiane, Laos (B. Phommasack, K. Bounlu) |