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Environmental Surveillance for Salmonella Typhi and its Association With Typhoid Fever Incidence in India and Malawi.

Authors :
Uzzell, Christopher B
Abraham, Dilip
Rigby, Jonathan
Troman, Catherine M
Nair, Satheesh
Elviss, Nicola
Kathiresan, Lalithambigai
Srinivasan, Rajan
Balaji, Veeraraghavan
Zhou, Nicolette A
Meschke, John Scott
John, Jacob
Kang, Gagandeep
Feasey, Nicholas
Mohan, Venkata Raghava
Grassly, Nicholas C
Source :
Journal of Infectious Diseases; 4/15/2024, Vol. 229 Issue 4, p979-987, 9p
Publication Year :
2024

Abstract

Background Environmental surveillance (ES) for Salmonella Typhi potentially offers a low-cost tool to identify communities with a high burden of typhoid fever. Methods We developed standardized protocols for typhoid ES, including sampling site selection, validation, characterization; grab or trap sample collection, concentration; and quantitative PCR targeting Salmonella genes (ttr , staG, and tviB) and a marker of human fecal contamination (HF183). ES was implemented over 12 months in a historically high typhoid fever incidence setting (Vellore, India) and a lower incidence setting (Blantyre, Malawi) during 2021–2022. Results S. Typhi prevalence in ES samples was higher in Vellore compared with Blantyre; 39/520 (7.5%; 95% confidence interval [CI], 4.4%–12.4%) vs 11/533 (2.1%; 95% CI, 1.1%–4.0%) in grab and 79/517 (15.3%; 95% CI, 9.8%–23.0%) vs 23/594 (3.9%; 95% CI, 1.9%–7.9%) in trap samples. Detection was clustered by ES site and correlated with site catchment population in Vellore but not Blantyre. Incidence of culture-confirmed typhoid in local hospitals was low during the study and zero some months in Vellore despite S. Typhi detection in ES. Conclusions ES describes the prevalence and distribution of S. Typhi even in the absence of typhoid cases and could inform vaccine introduction. Expanded implementation and comparison with clinical and serological surveillance will further establish its public health utility. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00221899
Volume :
229
Issue :
4
Database :
Complementary Index
Journal :
Journal of Infectious Diseases
Publication Type :
Academic Journal
Accession number :
176589880
Full Text :
https://doi.org/10.1093/infdis/jiad427