1 Department of Epidemiology, Johns Hopkins Bloomberg, School of Public Health, Baltimore, MD, USA.
2 Partners In Health/Zanmi, Lasante, Port-au-Prince, Haiti.
3 Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115, USA; Center for Global Health, Massachusetts General Hospital, Boston, MA, USA. Electronic address: LIVERS@mgh.harvard.edu.