{ "abstract": "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.", "abstract_shown": true, "affiliations": [ "Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand", "Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom", "Aix Marseille University, IRD, INSERM, SESSTIM, ISSPAM, Marseille, France", "Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand", "National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia", "Action for Health Development, Battambang, Cambodia", "Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia", "Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom", "Department of Infectious Diseases, Monash University and Alfred Hospital, Melbourne, Victoria, Australia", "The Open University, Milton Keynes, United Kingdom", "Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, United States of America", "Department of Public Health Sciences, University of California Davis School of Medicine, Davis, California, United States of America" ], "article_type": "Research Article", "arxiv": null, "author_total": 16, "authors": [ { "affs": [ 0 ], "name": "Meiwen Zhang" }, { "affs": [ 1 ], "name": "Natnaree Saiprom" }, { "affs": [ 2 ], "name": "Rupam Tripura" }, { "affs": [ 3 ], "name": "Lek Dysoley" }, { "affs": [ 4 ], "name": "Phal Chanpheakdey" }, { "affs": [ 5 ], "name": "Vanna Moul" }, { "affs": [ 6 ], "name": "Arjun Chandna" }, { "affs": [ 7 ], "name": "Elizabeth M. Batty" }, { "affs": [ 8 ], "name": "Sue J. Lee" }, { "affs": [ 9 ], "name": "Richard J. Maude" }, { "affs": [ 10 ], "name": "Nicholas P. J. Day" }, { "affs": [ 11 ], "name": "Thomas J. Peto" }, { "name": "Narisara Chantratita" }, { "name": "Richelle Charles" }, { "name": "Yoel Lubell" }, { "name": "Kristen Aiemjoy" } ], "bibtex": "https://research.draconitic.com/paper/7vx0xapnj2sfm.bib", "cited_by": 0, "doi": "10.1371/journal.pntd.0014691", "fulltext_url": "https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014691", "id": "7vx0xapnj2sfm", "issns": [ "1935-2735" ], "landing_url": "https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014691", "language": null, "licence": "CC-BY-4.0", "licence_label": "CC BY 4.0", "licence_source": "journal", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "1106|Salmonella and Campylobacter epidemiology" ], [ "plos", "/Biology and life sciences/Biochemistry/Proteins/Immune system proteins/Antibodies" ], [ "plos", "/Biology and life sciences/Immunology/Immune system proteins/Antibodies" ], [ "plos", "/Biology and life sciences/Microbiology/Medical microbiology/Microbial pathogens/Bacterial pathogens/Salmonella/Salmonella typhi" ], [ "plos", "/Biology and life sciences/Organisms/Bacteria/Enterobacteriaceae/Salmonella/Salmonella typhi" ], [ "plos", "/Biology and life sciences/Physiology/Immune physiology/Antibodies" ], [ "plos", "/Medicine and health sciences/Clinical medicine/Signs and symptoms/Fevers" ], [ "plos", "/Medicine and health sciences/Epidemiology" ], [ "plos", "/Medicine and health sciences/Health care/Environmental health/Sanitation" ], [ "plos", "/Medicine and health sciences/Immunology/Immune system proteins/Antibodies" ], [ "plos", "/Medicine and health sciences/Medical conditions/Infectious diseases/Bacterial diseases/Salmonella/Salmonella typhi" ], [ "plos", "/Medicine and health sciences/Pathology and laboratory medicine/Pathogens/Microbial pathogens/Bacterial pathogens/Salmonella/Salmonella typhi" ], [ "plos", "/Medicine and health sciences/Public and occupational health/Environmental health/Sanitation" ], [ "plos", "/People and places/Geographical locations/Asia/Cambodia" ], [ "plos", "/People and places/Population groupings/Age groups" ], [ "plos", "/Research and analysis methods/Immunologic techniques/Immunoassays/Enzyme-linked immunoassays" ] ], "openalex": "W7117303392", "pdf_url": "https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0014691&type=printable", "pmcid": null, "pmid": null, "published": "2026-09-02", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/7vx0xapnj2sfm.ris", "sources": [ { "first_seen": "2026-10-30T12:18:02Z", "native_id": "10.1371/journal.pntd.0014691", "source": "plos", "url": "https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0014691" } ], "subjects": [ { "field": "biology", "origin": "plos:immunology", "subfield": "immunology" }, { "field": "biology", "origin": "plos:microbiology", "subfield": "microbiology" }, { "field": "medicine", "origin": "plos:epidemiology", "subfield": "epidemiology-public-health" } ], "title": "Estimating enteric fever seroincidence in rural western Cambodia: Findings from a population-based cross-sectional serosurvey", "title_text": "Estimating enteric fever seroincidence in rural western Cambodia: Findings from a population-based cross-sectional serosurvey", "type": "peer-reviewed", "updated_at": "2026-10-30T12:18:02Z", "url": "https://research.draconitic.com/paper/7vx0xapnj2sfm", "venue": "PLOS Neglected Tropical Diseases", "versions": [] }