Fig 1.
Conceptual figure describing a broad approach for environmental surveillance to monitor soil-transmitted helminth infections.
Created with BioRender.com.
Table 1.
Household characteristics in each study site and overall.
Table 2.
Characteristics of soil samples collected in each study site and overall.
Fig 2.
STH detection in soil using qPCR versus ddPCR (A), with percent agreement (B) and Cohen’s Kappa statistic to assess strength of agreement (C). Criteria for positivity by ddPCR was an average of ≥3 positive droplets (2 replicates run).
Table 3.
Bivariate associations between soil characteristics and soil-transmitted helminth (STH) detection in soil samples (n = 449) by qPCR.
Table 4.
Overall household-level prevalence of soil-transmitted helminths (STH) detected by qPCR in soil and stool across all study sites in Benin, India, and Kenya.
Fig 3.
Household-level prevalence of A. lumbricoides, N. americanus, T. trichiura, and any soil-transmitted helminths (STH) by qPCR detection, stratified by country and sample type.
For stool samples, household-level prevalence is determined based on whether any stool samples (of up to 4) collected from a household were positive for a given STH target. A. duodenale and A. ceylanicum are not included due to low prevalence in soil and stool across all three countries.
Fig 4.
Unadjusted and adjusted associations between soil-transmitted helminth (STH) detection by qPCR in soil and matched human stool samples from 290 households in India, Kenya, and Benin.
Points represent odds ratios (OR) with 95% confidence interval (CI) error bars. Any STH indicates the sample was positive for at least one of the following targets: A. lumbricoides, T. trichiura, or N. americanus. Adjusted models included covariates associated (p < 0.20) with soil STH detection for each target, and all adjusted models including study site (country). Adjusted model for “Any STH” included variables for sun exposure, soil moisture content, whether the sampling area was visibly wet, and whether the sampling area had visible feces nearby; N. americanus adjusted model included soil type and moisture content; A. lumbricoides adjusted model included sample type, soil type, soil moisture, sun exposure, whether the sampling area was visibly wet, and whether there was visible feces; T. trichiura adjusted model included sample type, soil moisture, pH, sun exposure, and whether the sampling area was visibly wet.