# Soil epidemiology: a new tool for environmental surveillance of soil-transmitted helminth infections in endemic settings.

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 2024 · $111,347

## Abstract

PROJECT SUMMARY
 Soil-transmitted helminth (STH) infections (intestinal worms) affect 1.5 billion individuals
globally. Recent evidence from trials and modeling studies suggests that community-wide mass
drug administration (cMDA) of deworming medication with sufficient coverage and adherence
can eliminate STH transmission. However, in settings with ongoing environmental transmission
and low coverage of networked sanitation, persistent environmental reservoirs of STH eggs
result in high reinfection rates, and hinder progress towards elimination.
 STH control programs use human stool-based methods to assess STH prevalence and
intensity in endemic settings. However, individual stool sampling is expensive and logistically
difficult, particularly when human infection prevalence is low. If collecting and analyzing soil from
locations in communities with high human activity (e.g. home entrances, water collection points,
schools) were established to be equally or more sensitive than human stool diagnostics, this
approach may represent a less invasive and more cost-effective surveillance tool for MDA
program monitoring and evaluation.
 This study will leverage a multi-country cluster-randomized controlled trial delivering
three-years of biannual cMDA in Benin and India (DeWorm3). The trial will collect and analyze
by qPCR, human stool samples 24 months (n=80,000 in total) after the final round of cMDA,
which will yield highly accurate human STH infection prevalence estimates in the study areas.
Through extensive laboratory studies and field testing in India and Benin, our team has
developed a sensitive and specific molecular method for detecting STH environmental DNA
(eDNA) in large volumes of soil. We will nest soil sampling within the trial at the same time point
as human stool collection and one year later with the specific aims to: 1) Quantify the effect of a
biannual cMDA intervention on the soil STH reservoir; 2) Determine whether soil STH eDNA
levels can predict community-level human STH infection prevalence; and 3) Develop the optimal
soil sampling strategy and compare costs to human stool-based surveillance.
 Pairing soil STH eDNA assessments with human infection prevalence data already
being collected by the DeWorm3 trial is a unique and time sensitive opportunity to validate and
test the utility of environmental STH surveillance. Our findings will also contribute to
understanding the conditions under which MDA program integration with improved sanitation
interventions is needed for achieving sustained reductions in STH infection prevalence.

## Key facts

- **NIH application ID:** 11045205
- **Project number:** 3R01AI155739-04S1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Sitara Swarna Rao Ajjampur
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $111,347
- **Award type:** 3
- **Project period:** 2021-07-13 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11045205

## Citation

> US National Institutes of Health, RePORTER application 11045205, Soil epidemiology: a new tool for environmental surveillance of soil-transmitted helminth infections in endemic settings. (3R01AI155739-04S1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/11045205. Licensed CC0.

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