[1] Johns Hopkins Univ, Sch Med, Dept Med, Div Infect Dis, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Sch Med, Dept Med, Div Internal Med, Baltimore, MD 21205 USA
[3] Johns Hopkins Univ, Sch Med, Dept Med, Div Gastroenterol, Baltimore, MD 21205 USA
[4] Univ Fed Ceara, Div Infect Dis, Clin Res Unit, Fortaleza, Ceara, Brazil
[5] Univ Fed Ceara, Div Clin Pharmacol, Clin Res Unit, Fortaleza, Ceara, Brazil
[6] Univ Virginia, Sch Med, Dept Med, Div Geog Med, Charlottesville, VA 22908 USA