Studies to Control Endemic Typhoid Fever in Chile

A multi-faceted program of applied research has been undertaken in collaboration with the Ministry of Health of Chile intended to lead to control of endemic typhoid fever in Santiago, Chile. Information derived from these studies is directly applicable to the prevention of typhoid fever in United States military personnel deployed in endemic areas. During the past contract year, activities that were emphasized include: Maintenance of prospective epidemiologic and bacteriologic surveillance in three large-scale field trials evaluating the efficacy of Ty21a live oral typhoid vaccine given in various formulations and immunization schedules. Epidemiologic studies to ascertain the modes of transmission of typhoid fever in Santiago, Chile to identify intervention points. Evaluation of a highly specific serological assay that measures Vi antibody as a screening test to detect the presence of chronic Salmonella typhi carriers in epidemiologically important populations such as foodhandlers.