Changes in enteric fever trends during the COVID-19 pandemic from the Surveillance for Enteric Fever in Asia Project: a cross-sectional study

Sira Jam Munira; Shiva R Naga; Irum Fatima Dehraj; Kate Doyle; Naito Kanon; Mohammad Tahir Yousafzai; Dipesh Tamrakar; Afshan Piyar Ali; Annaya Barman Jui; Alice S Carter; Dipu Chandra Das; Surrendar Dawani; Khalid Iqbal; Seema Irfan; Mohammad Shahidul Islam; Muhammad Ashraf Memon; Tuba Khan; Shamsun Nahar; Md Hafizur Rahman; Nasir Saleem Saddal; Jessica C Seidman; Rajeev Shrestha; Humaira Susmita; Jason R Andrews; Stephen P Luby; Denise O Garrett; Farah Naz Qamar; Samir K Saha; Senjuti Saha

doi:10.1016/j.lansea.2025.100562

Changes in enteric fever trends during the COVID-19 pandemic from the Surveillance for Enteric Fever in Asia Project: a cross-sectional study

Lancet Reg Health Southeast Asia. 2025 Mar 29:35:100562. doi: 10.1016/j.lansea.2025.100562. eCollection 2025 Apr.

Authors

Sira Jam Munira¹, Shiva R Naga^{2

3}, Irum Fatima Dehraj⁴, Kate Doyle⁵, Naito Kanon¹, Mohammad Tahir Yousafzai⁴, Dipesh Tamrakar^{2

3}, Afshan Piyar Ali⁶, Annaya Barman Jui¹, Alice S Carter⁵, Dipu Chandra Das¹, Surrendar Dawani⁷, Khalid Iqbal⁸, Seema Irfan⁹, Mohammad Shahidul Islam¹, Muhammad Ashraf Memon⁸, Tuba Khan¹⁰, Shamsun Nahar¹, Md Hafizur Rahman¹, Nasir Saleem Saddal¹¹, Jessica C Seidman⁵, Rajeev Shrestha^{12

13}, Humaira Susmita¹, Jason R Andrews¹⁴, Stephen P Luby¹⁴, Denise O Garrett⁵, Farah Naz Qamar⁴, Samir K Saha¹, Senjuti Saha¹

Affiliations

¹ Child Health Research Foundation, Dhaka, Bangladesh.
² Dhulikhel Hospital, Kavrepalanchok, Nepal.
³ Kathmandu University Hospital, Kathmandu, Nepal.
⁴ Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
⁵ Sabin Vaccine Institute, Washington, DC, USA.
⁶ Aga Khan University, Karachi, Pakistan.
⁷ Jinnah Postgraduate Medical Center, Karachi, Pakistan.
⁸ Clinical Laboratory, Kharadar General Hospital, Karachi, Pakistan.
⁹ Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan.
¹⁰ Kharadar General Hospital, Karachi, Pakistan.
¹¹ National Institute of Child Health, Karachi, Pakistan.
¹² Center for Infectious Disease Research & Surveillance, Dhulikhel Hospital, Kavrepalanchok, Nepal.
¹³ Research & Development Division, Dhulikhel Hospital, Kavrepalanchok, Nepal.
¹⁴ Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA, USA.

Abstract

Background: The Surveillance for Enteric Fever in Asia Project (SEAP) conducted blood culture surveillance for Salmonella enterica serotype Typhi (S. Typhi) and Paratyphi (S. Paratyphi) to provide an evidence base for prevention and control measures in Bangladesh, Nepal, and Pakistan.

Methods: From October 2020 to September 2022, we conducted prospective clinical surveillance and retrospective laboratory surveillance at health facilities in Dhaka, Bangladesh; Kathmandu and Kavrepalanchok, Nepal; and Karachi, Pakistan. Patients were eligible if they were outpatients with three or more days of fever in the last week. In Nepal and Pakistan, inpatients were eligible if they had suspected or confirmed enteric fever; in Bangladesh, only inpatients with confirmed enteric fever were enrolled. Patients with blood culture-confirmed enteric fever identified by hospital laboratories and laboratory network sites were also enrolled. Patients completed interviews and medical records were reviewed and abstracted. All enrolled patients had blood cultures performed. Antibiograms were performed to characterize drug sensitivity. We summarized the data descriptively.

Findings: A total of 17,593 patients were enrolled from 19 facilities. Of these, 8410 patients had culture-confirmed enteric fever. Case counts in all countries decreased in the early stages of the COVID-19 pandemic, but increased over time in Bangladesh and Pakistan. Case counts remained low throughout the study period in Nepal. In all countries, typhoid was more common than paratyphoid; the proportion of paratyphoid cases ranged from 8.4% in Pakistan to 16% in Nepal. Extensively drug-resistant typhoid was common in Pakistan (69%), but was not detected in Bangladesh or Nepal.

Interpretation: Cases of enteric fever decreased during the COVID-19 pandemic, though it is not clear how much of this decrease relates to true changes in transmission versus health-seeking behavior.

Funding: This project was funded by the Gates Foundation through INV-008335.

Keywords: Antimicrobial resistance; Bangladesh; Covid19 pandemic; Enteric fever; Nepal; Pakistan; Paratyphi; Paratyphoid; Southeast Asia; Surveillance; Typhi; Typhoid.