[1] Mahidol Univ, Siriraj Hosp, Fac Med, Dept Pediat, Bangkok 10700, Thailand
[2] Mahidol Univ, Siriraj Hosp, Fac Med, Dept Pathol, Bangkok 10700, Thailand
[3] Mahidol Univ, Siriraj Hosp, Fac Med, Dept Microbiol, Bangkok 10700, Thailand
[4] Thai Minis Publ Hlth, Int Emerging Infect Program, Bangkok, Thailand
[5] Ctr Dis Control & Prevent, Atlanta, GA USA