Search

BACKGROUND: One-fifth of the global population is infected with soil-transmitted helminths (STH). Mass drug administration (MDA) with deworming medication is widely implemented to control morbidity associated with STH infections. However, surveillance of human infection prevalence by collecting individual stool samples is time-consuming, costly, often stigmatized, and logistically challenging. Current methods of STH detection are poorly sensitive, particularly in low-intensity and low-prevalence populations. METHODOLOGY/PRINCIPAL FINDINGS: We aimed to develop a sensitive and specific molecular method for detecting STH DNA in large volumes of soil (20 g) by conducting laboratory and proof of concept studies across field sites in Kenya, Benin, and India. We collected human stool (n = 669) and soil (n = 478) from 322 households across the three study sites. We developed protocols for DNA extraction from 20 g of soil and qPCR to detect Ascaris lumbricoides, Trichuris trichiura, Necator americanus, and Ancylostoma duodenale. Agreement between detection of STH via qPCR, digital droplet PCR (ddPCR), and microscopy-based methods was assessed using the Cohens Kappa statistic. Finally, we estimated associations between soil characteristics and detection of STH in soil by qPCR, as well as between STH detected in soil and STH detected in stool from matched households, adjusting for soil characteristics. The overall prevalence of STH in soil by qPCR was 31% for A. lumbricoides, 3% for T. trichiura, and 13% for any hookworm species. ddPCR and qPCR performed similarly. However, there was poor agreement between STH detected in soil by qPCR versus light microscopy. Microscopy underestimated the prevalence of A. lumbricoides and N. americanus and overestimated T. trichiura. Detection of an STH species in household soil was strongly associated with increased odds of a household member being infected with that same species. CONCLUSIONS/SIGNIFICANCE: Soil surveillance for STH has several benefits over stool-based surveillance, including lower cost and higher success rates for sample collection. Considering that delivery of MDA occurs at the community level, environmental surveillance using molecular methods could be a cost-effective alternate strategy for monitoring STH in these populations.

Background: Following the conclusion of a stepped-wedge cluster randomized trial of the Systems Analysis and Improvement Approach (SAIA) to optimize the prevention of mother-to-child HIV transmission cascade in Manica Province, Mozambique, we conducted a natural experiment to test the sustainability of the delivery model with limited financial inputs., Methods: District nurse supervisors were encouraged to continue to facilitate SAIA cycles in subordinate health facilities and provided phone credit and tablet access to upload implementation data. No additional resources (eg, funds for transport, refreshments, or supplies) were provided. Barriers to implementation were collected via conversations with district supervisors., Results: Monthly facilitation of SAIA cycles continued in 11 of 12 (92%) districts and 13 of 36 (36%) facilities through 12 months posttrial, which declined to 10 districts and 10 facilities by the end of the 15-month posttrial period. Despite interest among district supervisors to continue implementation, logistical and financial barriers prevented visits to facilities not in close proximity to district management offices. Turnover of district supervisors resulted in replacements not having knowledge and experience facilitating SAIA. The lack of refreshments for facility staff and limited supplies (pens and papers) were cited as additional barriers., Conclusion: Despite the scalability of the SAIA model, it is susceptible to implementation decay without sufficient health system resources. Additional research is needed to test sustainment strategies that address identified barriers and enable continued delivery of the implementation strategy core components at a sufficient level of fidelity to maintain desired health system improvements and patient-level outcomes., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)