The epidemiology of typhoid fever in the Dhulikhel area, Nepal: A prospective cohort study

INTRODUCTION: Typhoid fever (TF) continues to cause considerable morbidity and mortality in Nepal, but only limited epidemiologic data is available about TF outside Kathmandu. METHODS: As part of an interventional trial, we performed a prospective cohort study of bacteremic TF patients in Dhulikhel Hospital between October 2012 and October 2014. Demographic, epidemiological, clinical, and microbiologic data were recorded. RESULTS: 116 bacteremic typhoid patients were included in the study. Most were young, healthy, adults (mean age 27.9±12 years), 41.4% of whom were female. More than 70% of patients were employed in non-manual services or were university students. Salmonella Typhi accounted for 64/115 (55.7%) of all isolates, while Salmonella Paratyphi accounted for 51/115 (44.3%), of which 42 were Paratyphi A and 9 Paratyphi B. A significant proportion of TF cases occurred also during the dry season (48/116, 41.6%). The clinical presentation of Salmonella Typhi and Paratyphi infections was similar, except for a greater proportion of arthralgia in patients with Salmonella Typhi. Most Salmonella Typhi and Paratyphi isolates were resistant to nalidixic acid and susceptible to older antibiotics. One Salmonella Paratyphi isolate was resistant to ceftriaxone. CONCLUSIONS: TF remains common in the Dhulikhel area, even among those with a high level of education. Public health measures aimed at reducing the incidence of TF in the Dhulikhel area are warranted. The relative burden of TF caused by Salmonella Paratyphi is rising; a vaccine with activity against Salmonella Paratyphi is needed. Since Salmonella Paratyphi B was more prevalent in this cohort than in large cohorts of patients from Kathmandu, it is likely that there are significant regional variations in the epidemiology of TF outside Kathmandu.