Estimating enteric fever seroincidence in rural western Cambodia: Findings from a population-based cross-sectional serosurvey

@article{zhang2026estimating,
  title = {{Estimating enteric fever seroincidence in rural western Cambodia: Findings from a population-based cross-sectional serosurvey}},
  author = {Meiwen Zhang and Natnaree Saiprom and Rupam Tripura and Lek Dysoley and Phal Chanpheakdey and Vanna Moul and Arjun Chandna and Elizabeth M. Batty and Sue J. Lee and Richard J. Maude and Nicholas P. J. Day and Thomas J. Peto and Narisara Chantratita and Richelle Charles and Yoel Lubell and Kristen Aiemjoy},
  journal = {PLOS Neglected Tropical Diseases},
  year = {2026},
  month = sep,
  doi = {10.1371/journal.pntd.0014691},
  url = {https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014691},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - Estimating enteric fever seroincidence in rural western Cambodia: Findings from a population-based cross-sectional serosurvey
AU  - Meiwen Zhang
AU  - Natnaree Saiprom
AU  - Rupam Tripura
AU  - Lek Dysoley
AU  - Phal Chanpheakdey
AU  - Vanna Moul
AU  - Arjun Chandna
AU  - Elizabeth M. Batty
AU  - Sue J. Lee
AU  - Richard J. Maude
AU  - Nicholas P. J. Day
AU  - Thomas J. Peto
AU  - Narisara Chantratita
AU  - Richelle Charles
AU  - Yoel Lubell
AU  - Kristen Aiemjoy
PY  - 2026
DA  - 2026/09/02
JO  - PLOS Neglected Tropical Diseases
DO  - 10.1371/journal.pntd.0014691
UR  - https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014691
AB  - Introduction: Enteric fever, caused by Salmonella enterica serovars Typhi and Paratyphi, remains an important cause of febrile illness in low- and middle-income countries (LMIC). However, the exact burden is difficult to estimate due to limitations in diagnosis and surveillance. Methods: Samples from a representative cross-sectional household serosurvey in rural western Cambodia were used to estimate enteric fever seroincidence among children and young adults. Participants were enrolled between April 7 and December 10, 2023, and 529 samples from individuals aged 5–25 years were analysed. Using IgA and IgG responses to hemolysin E antigen and established models of antibody decay after infection, we estimated seroincidence, conveying the rate of new infection in the population over time. Results: The overall enteric fever seroincidence rate was 161.8/1,000 person-years (95%CI: 147.5, 177.5). Among children 5–15 years, it ranged between 149.5 (95%CI: 120.8, 185.1) and 239.0 (95%CI:188.7, 302.7) across districts. Seroincidence was higher among children 5–15 years from households with unimproved drinking water sources or sanitation facilities, and in districts with a higher proportion of households with unimproved WASH. Conclusion: These findings potentially support the introduction of the typhoid conjugate vaccine in rural western Cambodia. However, additional data on the relative contribution of S. Typhi versus S. Paratyphi is needed. We also demonstrate seroincidence as an adjunctive valuable surveillance tool in LMICs where facility-based surveillance may be inadequate. Author summary: Enteric fever caused by the bacteria Salmonella enterica serovars Typhi and Paratyphi, remains common in many low- and middle-income countries, including Cambodia. Its true burden is often unclear because routine diagnosis and surveillance miss many cases. In this study, we measured antibodies to enteric fever pathogens in blood samples from children and young adults aged 5–25 years collected during a cross-sectional household survey in rural western Cambodia. Because after infection, antibody levels rise and decline in predictable ways, these patterns can be used to estimate how frequently new infections occur in the community even from samples collected at a single timepoint. We found infection rates substantially higher than suggested by clinical reports, including among children aged 5–15 years- the main target group of the typhoid vaccine, particularly those living in districts with poorer water and sanitation. These findings support consideration of the typhoid vaccine introduction. However, additional blood culture data is needed to determine the relative contribution of S. Typhi and S. Paratyphi, because only S. Typhi is vaccine-preventable, while improving water and sanitation to reduce transmission of both. Broadly, our study shows how antibody-based approaches can support infectious diseases surveillance.
SN  - 1935-2735
ER  -