Risk factors for typhoid fever in the Mekong delta, southern Viet Nam: a case-control study

In order to identify risk factors for typhoid fever in a highly endemic are a, we undertook a case-control study in the Mekong delta, Viet Nam. Cases w ere 144 consecutive patients admitted to hospital with blood culture-confir med typhoid fever. Two controls (1 in the hospital and 1 in the community) were chosen for each case. Standardized interviews were conducted with ques tions regarding recent contact with a typhoid fever patient, eating habits, hygiene and socio-economic level. Cases were more likely to have been in c ontact with a patient with typhoid fever than hospital controls (adjusted o dds ratio (OR) = 5.2, 95% confidence interval (95%CI) 1.7-15.9) or communit y controls (adjusted OR = 11.9, 95%CI 2.3-60.7); 11% and 14% of typhoid fev er cases (compared to hospital or community controls, respectively) were at tributable to recent contact with a patient with this disease. These findin gs suggest that strategies directed towards the persons in contact with a p atient might reduce the incidence of secondary cases of typhoid fever.