[1] Johns Hopkins Univ, Dept Med, Div Infect Dis, Baltimore, MD USA
[2] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD USA
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[4] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD USA
[5] Sun Yat Sen Univ, Affiliated Hosp 3, Dept Infect Dis, Guangzhou 510275, Guangdong, Peoples R China