Burden of typhoid and paratyphoid fever in a densely populated urban community, Dhaka, Bangladesh

Background: We conducted blood culture surveillance to estimate the incidence of typhoid and paratyphoid fever among urban slum residents in Dhaka, Bangladesh. Methods: Between January 7, 2003 and January 6, 2004, participants were visited weekly to detect febrile illnesses. Blood cultures were obtained at the clinic from patients with fever (≥38 °C). Salmonella isolates were assayed for antimicrobial susceptibility. Results: Forty Salmonella Typhi and eight Salmonella Paratyphi A were isolated from 961 blood cultures. The incidence of typhoid fever was 2.0 episodes/1000 person-years, with a higher incidence in children aged < 5 years (10.5/1000 person-years) than in older persons (0.9/1000 person-years) (relative risk. = 12, 95% confidence interval (CI) 6.3-22.6). The incidence of paratyphoid fever was 0.4/1000 person-years without variation by age group. Sixteen S. Typhi isolates were multidrug-resistant (MDR). All S. Paratyphi isolates were pan-susceptible. The duration of fever among patients with an MDR S. Typhi infection was longer than among patients with non-MDR S. Typhi (16 ± 8 vs. 11 ± 4 days, p= 0.02) and S. Paratyphi (10 ± 2 days, p= 0.04) infections. Conclusions: Typhoid fever is more common than paratyphoid fever in the urban Bangladeshi slum; children < 5 years old have the highest incidence. Multidrug resistance is common in S. Typhi isolates and is associated with prolonged illness. Strategies for typhoid fever prevention in children aged < 5 years in Bangladesh, including immunization, are needed.