[1] Minist Publ Hlth, HIV AIDS Collaborat, Nonthaburi 11000, Thailand
[2] Guangxi AIDS Surveillance & Testing Ctr, Nanning 530021, Guangxi, Peoples R China
[3] Ctr Dis Control & Prevent, Atlanta, GA 30333 USA
[4] Minist Publ Hlth, Dept Med Sci, Natl Inst Hlth, Nonthaburi 11000, Thailand