An outbreak of typhoid fever was observed in a group of students and a
ccompanying teachers during a journey to Haiti in summer 1991. All (6)
infected persons were symptomatic and rapidly cured by antibiotics. T
he Salmonella typhi strains isolated from blood cultures were all iden
tical by ribotyping. All the participants had a medical checkup and st
ool cultures were obtained; asymptomatic carriers could be excluded. S
econdarily infected persons were not observed. The infectious source h
as not been identified, but various hypotheses are considered. Oral va
ccination does not appear to modify the risk of infection in exposed p
ersons.