Wastewater surveillance for Salmonella Typhi and its association with seroincidence of enteric fever in Vellore, India.

IF 3.4 2区医学 Q1 PARASITOLOGY

PLoS Neglected Tropical Diseases Pub Date : 2025-03-03 eCollection Date: 2025-03-01 DOI:10.1371/journal.pntd.0012373

Dilip Abraham, Lalithambigai Kathiresan, Midhun Sasikumar, Kristen Aiemjoy, Richelle C Charles, Dilesh Kumar, Rajan Srinivasan, Catherine Troman, Elizabeth Gray, Christopher B Uzzell, Jacob John, Balaji Veeraraghavan, Nicholas C Grassly, Venkata Raghava Mohan

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引用次数: 0

Abstract

Background: Blood culture-based surveillance for typhoid fever has limited sensitivity, and operational challenges are encountered in resource-limited settings. Environmental surveillance targeting Salmonella Typhi (S. Typhi) shed in wastewater (WW), coupled with cross-sectional serosurveys of S. Typhi-specific antibodies estimating exposure to infection, emerges as a promising alternative.

Methods: We assessed the feasibility and effectiveness of wastewater (WW) and sero-surveillance for S. Typhi in Vellore, India, from May 2022 to April 2023. Monthly samples were collected from 40 sites in open drainage channels and processed using standardized protocols. DNA was extracted and analyzed via quantitative PCR for S. Typhi genes (ttr, tviB, staG) and the fecal biomarker HF183. Clinical cases of enteric fever were recorded from four major hospitals, and a cross-sectional serosurvey measured hemolysin E (HlyE) IgG levels in children under 15 years of age to estimate seroincidence.

Results: 7.50% (39/520) of grab and 15.28% (79/517) Moore swabs were positive for all 3 S. Typhi genes. Moore swab positivity was significantly associated with HF183 (adjusted odds ratio (aOR): 3.08, 95% CI: 1.59-5.95) and upstream catchment population (aOR: 4.67, 1.97-11.04), and there was increased detection during monsoon season - membrane filtration (aOR: 2.99, 1.06-8.49), and Moore swab samples (aOR: 1.29, 0.60-2.79). Only 11 blood culture-confirmed typhoid cases were documented over the study period. Estimated seroincidence was 10.4/100 person-years (py) (95% CI: 9.61 - 11.5/100 py). The number of S. Typhi positive samples at a site was associated with the estimated sero-incidence in the site catchment population (incidence rate ratios: 1.14 (1.07-1.23) and 1.10 (1.02-1.20) for grab and Moore swabs respectively.

Conclusions: These findings underscore the utility and effectiveness of alternate surveillance approaches to estimating the incidence of S. Typhi infection in resource-limited settings, offering valuable insights for public health interventions and disease monitoring strategies where conventional methods are challenging to implement.

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印度Vellore污水中伤寒沙门氏菌监测及其与肠道热血清发病率的关系。

背景：基于血液培养的伤寒监测灵敏度有限，并且在资源有限的情况下遇到操作挑战。针对污水中伤寒沙门菌（S. Typhi）的环境监测，加上伤寒沙门菌特异性抗体的横断面血清调查，作为一种有希望的替代方法出现。方法：对2022年5月至2023年4月在印度Vellore市进行伤寒沙门氏菌废水（WW）和血清监测的可行性和有效性进行评估。每月从40个露天排水渠道收集样本，并使用标准化方案进行处理。提取DNA，采用定量PCR检测伤寒沙门氏菌基因（ttr、tviB、staG）和粪便生物标志物HF183。从四家主要医院记录肠热病的临床病例，并进行横断面血清调查，测量15岁以下儿童的溶血素E (HlyE) IgG水平，以估计血清发病率。结果：7.50%（39/520）的grab和15.28%（79/517）的Moore拭子对3种伤寒沙门氏菌基因均呈阳性。摩尔拭子阳性与HF183（校正优势比（aOR）： 3.08, 95% CI: 1.59 ~ 5.95）和上游流域人群（aOR: 4.67, 1.97 ~ 11.04）显著相关，季风季节膜过滤（aOR: 2.99, 1.06 ~ 8.49）和摩尔拭子样本（aOR: 1.29, 0.60 ~ 2.79）检出率增加。在研究期间，只有11例经血液培养证实的伤寒病例被记录在案。估计血清发病率为10.4/100人-年（95% CI: 9.61 - 11.5/100 py）。一个地点的伤寒沙门氏菌阳性样本数量与该地点集水区人群的估计血清发病率相关(抓拭和摩尔拭子的发病率比分别为1.14（1.07-1.23）和1.10（1.02-1.20）。结论：这些发现强调了在资源有限的环境中，替代监测方法在估计伤寒沙门氏菌感染发生率方面的效用和有效性，为传统方法难以实施的公共卫生干预和疾病监测策略提供了有价值的见解。

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来源期刊

PLoS Neglected Tropical Diseases PARASITOLOGY-TROPICAL MEDICINE

自引率

10.50%

发文量

723

期刊介绍： PLOS Neglected Tropical Diseases publishes research devoted to the pathology, epidemiology, prevention, treatment and control of the neglected tropical diseases (NTDs), as well as relevant public policy. The NTDs are defined as a group of poverty-promoting chronic infectious diseases, which primarily occur in rural areas and poor urban areas of low-income and middle-income countries. Their impact on child health and development, pregnancy, and worker productivity, as well as their stigmatizing features limit economic stability. All aspects of these diseases are considered, including: Pathogenesis Clinical features Pharmacology and treatment Diagnosis Epidemiology Vector biology Vaccinology and prevention Demographic, ecological and social determinants Public health and policy aspects (including cost-effectiveness analyses).