Timeframe for suspecting typhoid fever post-travel in Canadian children

Typhoid fever, caused by Salmonella enterica serotype Typhi, remains a concern in non-endemic regions, particularly for travelers returning from endemic areas, as it can cause severe systemic infections. Complications, such as gastrointestinal bleeding, could be avoided with timely diagnosis and management, and the optimal timeframe for clinical suspicion post-travel remains debated. This study aimed to determine the post-travel period during which clinicians should suspect typhoid fever in children returning to Canada.

This was a secondary analysis of two cohort studies conducted in a tertiary care pediatric hospital in Montreal, Canada between 2018 and 2024. The full cohorts included all children with positive blood cultures from the emergency department (ED), while this study focusses on Salmonella Typhi bacteremia. The primary outcome was the number of days between return to Canada and positive blood culture. Independent variables included age, sex, fever at triage, country visited, and medical history. For participants who had traveled, the analysis focused on the time, in days, between the date of return from travel and presentation at the ED.

Out 38,541 blood cultures drawn, 368 bacteremia cases were identified. Of these, seven (1.9%) were caused by Salmonella Typhi. The median delay between return and presentation was 23 days (range: 7-49 days). Four patients had traveled to India and two to Pakistan, with four of the six cases presented to the ED more than 3 weeks post-travel. One patient had not traveled but had exposure to a potential carrier returning from Ivory Coast. Of note, most cases were initially misdiagnosed as viral illness.

Our small study demonstrated delays up to 7 weeks between travel and clinical presentation of typhoid fever in a cohort of children in a Canadian ED. This emphasizes the importance of collecting travel history in febrile children.