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

Abstract

BackgroundWe conducted blood culture surveillance to estimate the incidence of typhoid and paratyphoid fever among urban slum residents in Dhaka, Bangladesh. MethodsBetween 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. ResultsForty 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. ConclusionsTyphoid 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.