[1] Univ Zurich, WHO Collaborating Ctr Travellers Hlth, Epidemiol Biostat & Prevent Inst, Div Infect Dis,Dept Publ Hlth, Zurich, Switzerland
[2] Univ Texas Sch Publ Hlth, Div Epidemiol Human Genet & Environm Sci, Houston, TX USA
[3] Harvard Univ, Dept Global Hlth & Populat, Harvard TH Chan Sch Publ Hlth, Boston, MA 02115 USA
[4] Univ Calif San Francisco, Global Hlth Sci, San Francisco, CA 94143 USA