Effects of single and integrated water, sanitation, handwashing, and nutrition interventions on child soil-transmitted helminth and giardia infections: A cluster-randomized controlled trial in rural Kenya

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Study Justification:
– Helminth and protozoan infections affect over 1 billion children worldwide.
– Water quality, sanitation, handwashing, and nutrition interventions could be more sustainable control strategies for parasite infections than mass drug administration.
– This study aimed to assess the effects of single and integrated interventions on child soil-transmitted helminth and Giardia infections in rural Kenya.
Highlights:
– The study enrolled pregnant women in rural western Kenya into a cluster-randomized controlled trial.
– Six interventions were tested: water treatment, improved sanitation, handwashing with soap, combined water treatment, sanitation, and handwashing, improved nutrition, and combined water treatment, sanitation, handwashing, and nutrition.
– After 2 years of intervention exposure, stool samples were collected from 9,077 children aged 2 to 15 years in 622 clusters.
– The analysis showed that water treatment, combined water treatment, sanitation, and handwashing, and combined water treatment, sanitation, handwashing, and nutrition interventions reduced the prevalence of Ascaris infection compared to the control group.
– No intervention reduced Giardia infection.
Recommendations:
– Integration of improved water quality, sanitation, and handwashing could contribute to sustainable control strategies for Ascaris infections.
– Combining nutrition with water, sanitation, and handwashing did not provide additional benefits.
– Drinking water should be given increased attention as a transmission pathway for Ascaris.
Key Role Players:
– Community health promoters
– Field staff
– Lab technicians
– Data analysts
Cost Items for Planning Recommendations:
– Chlorine treatment of drinking water
– Provision of toilets with plastic slabs and hardware
– Handwashing stations with foot-pedal-operated jerry cans
– Small-quantity lipid-based nutrient supplements
– Behavior change package materials (flip charts, posters, reminder cue cards)
– Intervention-specific hardware, products, or supplements
– Monthly visits from promoters
– Refilling soap regularly
– Training for community health promoters
– Transportation of stool samples to field labs
– Analysis of stool samples by microscopy and quantitative polymerase chain reaction
Please note that the cost items provided are for planning purposes and not actual costs.

The strength of evidence for this abstract is 8 out of 10.
The evidence in the abstract is strong, but there are some limitations that could be addressed to improve it. The study design is a cluster-randomized controlled trial, which is a robust design for evaluating interventions. The trial included a large number of participants (9,077 children) and measured the effects of 6 different interventions on parasite infections. The results showed that water treatment, combined water treatment, sanitation, and handwashing, and combined water treatment, sanitation, handwashing, and nutrition interventions were effective in reducing Ascaris infection prevalence. However, there were no observed differences in Ascaris infection prevalence between the control group and the individual interventions of sanitation, handwashing, or nutrition. The study also found that integrating nutrition with water, sanitation, and handwashing did not provide additional benefits. The evidence was supported by reanalysis of stool samples using quantitative polymerase chain reaction. The study had some limitations, including imperfect uptake of intervention behaviors and limited power to detect effects on rare parasite infections. It was also not feasible to blind participants and sample collectors to treatment status. However, lab technicians and data analysts were blinded to treatment status. To improve the evidence, future studies could focus on improving the uptake of intervention behaviors and increasing the power to detect effects on rare parasite infections. Blinding of participants and sample collectors could also be considered if feasible.

Background Helminth and protozoan infections affect more than 1 billion children globally. Improving water quality, sanitation, handwashing, and nutrition could be more sustainable control strategies for parasite infections than mass drug administration, while providing other quality of life benefits. Methods and findings We enrolled geographic clusters of pregnant women in rural western Kenya into a cluster-randomized controlled trial (ClinicalTrials.gov NCT01704105) that tested 6 interventions: water treatment, improved sanitation, handwashing with soap, combined water treatment, sanitation, and handwashing (WSH), improved nutrition, and combined WSH and nutrition (WSHN). We assessed intervention effects on parasite infections by measuring Ascaris lumbricoides, Trichuris trichiura, hookworm, and Giardia duodenalis among children born to the enrolled pregnant women (index children) and their older siblings. After 2 years of intervention exposure, we collected stool specimens from 9,077 total children aged 2 to 15 years in 622 clusters, including 2,346 children in an active control group (received household visits but no interventions), 1,117 in the water treatment arm, 1,160 in the sanitation arm, 1,141 in the handwashing arm, 1,064 in the WSH arm, 1,072 in the nutrition arm, and 1,177 in the WSHN arm. In the control group, 23% of children were infected with A. lumbricoides, 1% with T. trichiura, 2% with hookworm, and 39% with G. duodenalis. The analysis included 4,928 index children (median age in years: 2) and 4,149 older siblings (median age in years: 5); study households had an average of 5 people, 90% had dirt floors. Compared to the control group, Ascaris infection prevalence was lower in the water treatment arm (prevalence ratio [PR]: 0.82 [95% CI 0.67, 1.00], p = 0.056), the WSH arm (PR: 0.78 [95% CI 0.63, 0.96], p = 0.021), and the WSHN arm (PR: 0.78 [95% CI 0.64, 0.96], p = 0.017). We did not observe differences in Ascaris infection prevalence between the control group and the arms with the individual interventions sanitation (PR: 0.89 [95% CI 0.73, 1.08], p = 0.228), handwashing (PR: 0.89 [95% CI 0.73, 1.09], p = 0.277), or nutrition (PR: 86 [95% CI 0.71, 1.05], p = 0.148). Integrating nutrition with WSH did not provide additional benefit. Trichuris and hookworm were rarely detected, resulting in imprecise effect estimates. No intervention reduced Giardia. Reanalysis of stool samples by quantitative polymerase chain reaction confirmed the reductions in Ascaris infections measured by microscopy in the WSH and WSHN groups. Trial limitations included imperfect uptake of targeted intervention behaviors, limited power to detect effects on rare parasite infections, and that it was not feasible to blind participants and sample collectors to treatment status. However, lab technicians and data analysts were blinded to treatment status. The trial was funded by the Bill & Melinda Gates Foundation and the United States Agency for International Development. Conclusions Integration of improved water quality, sanitation, and handwashing could contribute to sustainable control strategies for Ascaris infections, particularly in similar settings with recent or ongoing deworming programs. Combining nutrition with WSH did not provide further benefits, and water treatment alone was similarly effective to integrated WSH. Our findings provide new evidence that drinking water should be given increased attention as a transmission pathway for Ascaris.

The trial protocol and detailed methods are published [28]. The trial was registered at ClinicalTrials.gov, identification number: {“type”:”clinical-trial”,”attrs”:{“text”:”NCT01704105″,”term_id”:”NCT01704105″}}NCT01704105. The study protocol was approved by the Committee for Protection of Human Subjects at the University of California, Berkeley (protocol number 2011-09-3654), the Institutional Review Board at Stanford University (IRB-23310), and the Scientific and Ethics Review Unit at the Kenya Medical Research Institute (protocol number SSC-2271). Innovations for Poverty Action enrolled participants, implemented the intervention delivery, and collected the data. Mothers provided written informed consent for themselves and their children. Clusters of eligible pregnant women were randomized by geographic proximal blocks into 1 of 8 study arms: water treatment (chlorine treatment of drinking water); improved sanitation(provision of toilets with plastic slabs and hardware to manage child feces); handwashing with soap; combined water treatment, sanitation, and handwashing (WSH); improved nutrition (infant and young child feeding counseling plus small-quantity lipid-based nutrient supplements [LNSs]); combined WSH and nutrition (WSHN); a double-sized active control; and a passive control. The trial included a passive control arm to test if promoter visits alone (active control) had an effect on the trial’s primary outcomes diarrhea and growth; children in the passive control arm were purposively excluded from parasitology measurement (Fig 1). STH, soil-transmitted helminth. We conducted a cluster-randomized trial because there could have been behavior and infectious disease interactions between neighboring households. Villages were eligible for selection into the study if they were rural, the majority of the population lacked access to piped water supplies, and there were no other ongoing WSH or nutrition programs. Within selected villages, a census was conducted to identify eligible pregnant women in their second or third trimester who planned to continue to live at their current residence for the next year. Since interventions were designed to reduce child exposure to pathogens through a cleaner environment and exclusive breastfeeding, we enrolled pregnant women to allow time for intervention delivery to occur prior to or as close to birth as possible. After the census, clusters were formed from 1–3 neighboring villages and had a minimum of 6 pregnant women per cluster after the enrollment survey (each village could only be assigned to 1 cluster). Enrolled study compounds were thus a small proportion of the total number of compounds residing in each cluster. Children born to enrolled pregnant women were considered “index” children. We measured parasite infections approximately 27 months post-enrollment (which equates to a minimum of 24 months of intervention exposure since intervention hardware was delivered <3 months after enrollment). Outcomes were assessed among index children, including twins, as well as among 1 older child in the index child’s compound to understand the effect of the interventions on both preschool-aged and school-aged children. The older child was selected by enrolling the youngest available child within the age range of 3–15 years old, with priority for a sibling in the index child’s household. A survey at enrollment measured household socioeconomic characteristics and demographics (including maternal age, maternal education, electricity access, type of floor, and number of people in the household), as well as water, sanitation, and handwashing infrastructure and behaviors (including type of water source, reported water treatment, defecation location, type of toilet, and presence of water and soap at a handwashing station). In addition, at study enrollment we measured Giardia, Entamoeba histolytica, and Cryptosporidium spp. among children residing in study compounds between 18 and 27 months of age (the projected age range for index children at the end of the study) to assess baseline prevalence of these pathogens. STHs were not measured at enrollment among these proxy children because it was not logistically feasible to deworm infected children at baseline. We also collected 100-ml samples from primary drinking water sources accessed by study households and household stored drinking water (if available). We transported the samples on ice to field labs and enumerated Escherichia coli in each sample by membrane filtration followed by culture on MI medium. A few weeks after enrollment, clusters were randomly assigned to intervention/control arms at the University of California, Berkeley, by an investigator independent of the field research team (BFA) using a random number generator. Groups of 9 geographically adjacent clusters were block-randomized into the 6 intervention arms, the double-sized active control arm, and the passive control arm (the passive control arm was not included in the parasite assessment). Participants and other community members were informed of their intervention/control group assignment after the baseline survey. Blinding (masking) of participants was not possible given the nature of the interventions. Data and stool sample collectors were not informed of cluster assignment, but could have inferred treatment status by observing intervention hardware. Lab technicians were blinded to intervention status. Two authors (AJP and JS) independently replicated the statistical analyses while blinded to intervention status. Intervention delivery occurred within 3 months after enrollment. In the water intervention arms (water treatment, WSH, and WSHN), community health promoters encouraged drinking water treatment with chlorine (liquid sodium hypochlorite) using either manual dispensers installed at the point of collection (community water source) in study villages or bottled chlorine provided directly to households every 6 months. In the sanitation intervention arms (sanitation, WSH, and WSHN), households in study compounds received new latrines, or existing latrines were upgraded and improved by installing a plastic slab that included a lid. All households in sanitation arm study compounds were provided with a child potty for each child 5,000 epg), following World Health Organization (WHO) cutoffs; prevalence of coinfection with 2 or 3 STHs; and prevalence of coinfection with Giardia and any STH. The trial’s original protocol included E. histolytica and Cryptosporidium spp. as additional protozoan endpoints. At enrollment, Giardia prevalence was 40% among 535 children 18–27 months old in study compounds, while Cryptosporidium spp. prevalence was 1% and E. histolytica prevalence was 0%. We determined that the extremely low baseline prevalence of E. histolytica and Cryptosporidium spp. made these trial endpoints futile due to limited statistical power, and since each required a separate assay on the ELISA platform, the study’s steering committee decided to not test for them at follow-up. All households in all clusters enrolled into the main trial were invited to participate in the measurement of parasite infections. The main trial was powered for a minimum detectable effect of 0.15 in length-for-age Z score and a relative risk of diarrhea of 0.7 or smaller for a comparison of any intervention with the double-sized control group, assuming a type I error (α) of 0.05 and power (1 − β) of 0.8, 10% loss to follow-up, and a 1-sided test for a 2-sample comparison of means (the main trial statistical analysis plan was later changed to employ 2-sided tests). This led to a planned design of 100 clusters per arm and 10 index children per cluster. Given this design and a single post-intervention measure, we estimated that the trial’s sample size would be sufficient at 80% power with a 2-sided α of 0.05 to detect a relative reduction of 18% in infection prevalence of any parasite (2-sided tests were planned due to a lack of evidence that all interventions would have a protective effect). Our minimum detectable effect calculations assumed 50% prevalence in the control arm, a village intraclass correlation (ICC) of 0.14, 2 children measured per enrolled household (index child plus an older sibling), and 70% successful stool collection and analysis. For perspective, this minimum detectable effect is much smaller than typical effect sizes reported in meta-analyses of the association between improved water, sanitation, and handwashing and helminth/protozoan infections (e.g., odds ratios between 0.46 and 0.58 for sanitation facilities and helminth infections) [2,31]. All statistical analyses and comparisons between arms (water treatment, sanitation, handwashing, WSH, nutrition, and WSHN compared to active control) were prespecified prior to unblinding of investigators, and the analysis plan was published with a time stamp on the Open Science Framework (https://osf.io/k2s47/). Replication scripts and data are also provided at the same link. Our alternative hypothesis for all comparisons was that group means were not equal (2-sided tests). We estimated unadjusted and adjusted intention-to-treat effect differences between study arms using targeted maximum likelihood estimation with influence-curve-based standard errors that treated clusters as independent units and allowed for outcome correlation within clusters [32,33]. Our parameters of interest for dichotomous outcomes were prevalence ratios (PRs) (prevalence in the intervention group divided by the prevalence in the control group). Our parameter of interest for helminth intensity was the relative fecal egg count reduction. We calculated the relative reduction using both geometric and arithmetic means. We did not perform statistical adjustments for multiple outcomes to preserve interpretation of effects and because many of our outcomes were correlated [34]. We estimated adjusted parameters by including variables that were associated with the outcome, to potentially improve the precision of our estimates. We prescreened covariates (S1 Text) to assess whether they were associated (p-value 8 people in compound, and time since defecation before stool collection. Statistical analyses were conducted using R version 3.3.2 (https://www.r-project.org).

The study mentioned in the description focuses on improving access to maternal health through various interventions. Some of the innovations used in the study include:

1. Water treatment: Chlorine treatment of drinking water to improve water quality and reduce the risk of waterborne infections.

2. Improved sanitation: Provision of toilets with plastic slabs and hardware to manage child feces, promoting safe and hygienic sanitation practices.

3. Handwashing with soap: Promotion of handwashing with soap to reduce the transmission of pathogens and improve overall hygiene.

4. Combined water treatment, sanitation, and handwashing (WSH): Integration of multiple interventions to create a comprehensive approach to improve access to clean water, sanitation, and hygiene practices.

5. Improved nutrition: Infant and young child feeding counseling, along with the provision of small-quantity lipid-based nutrient supplements (LNSs), to improve nutrition and overall health.

6. Combined WSH and nutrition (WSHN): Integration of water, sanitation, handwashing, and nutrition interventions to address multiple aspects of maternal and child health.

These innovations were implemented in a cluster-randomized controlled trial in rural Kenya to assess their effectiveness in reducing parasite infections and improving maternal and child health outcomes.
AI Innovations Description
The recommendation from the study is to integrate improved water quality, sanitation, and handwashing practices to improve access to maternal health. The study found that these interventions can contribute to sustainable control strategies for Ascaris infections, particularly in settings with ongoing deworming programs. The combination of water treatment, sanitation, and handwashing was more effective in reducing Ascaris infection prevalence compared to individual interventions. However, integrating nutrition with water, sanitation, and handwashing did not provide additional benefits. The study suggests that drinking water should be given increased attention as a transmission pathway for Ascaris. Overall, the findings highlight the importance of integrated approaches to improve access to maternal health and reduce parasite infections in children.
AI Innovations Methodology
The study described in the provided text aimed to evaluate the impact of different interventions on reducing parasite infections among children in rural Kenya. The interventions tested were water treatment, improved sanitation, handwashing with soap, improved nutrition, and combinations of these interventions. The study found that integrating improved water quality, sanitation, and handwashing (WSH) interventions could contribute to sustainable control strategies for Ascaris infections. However, integrating nutrition with WSH did not provide additional benefits, and water treatment alone was similarly effective to integrated WSH.

To simulate the impact of these recommendations on improving access to maternal health, a methodology could be developed as follows:

1. Define the objectives: Clearly state the specific goals of the simulation, such as assessing the potential impact of the interventions on maternal health outcomes, such as reducing maternal mortality rates or improving access to prenatal care.

2. Identify the key variables: Determine the key variables that are relevant to maternal health, such as the availability of prenatal care facilities, the number of skilled healthcare providers, the distance to healthcare facilities, and the prevalence of maternal health issues in the target population.

3. Collect data: Gather relevant data on the identified variables from reliable sources, such as government reports, health surveys, and academic studies. This data will serve as the basis for the simulation model.

4. Develop a simulation model: Create a mathematical or computational model that represents the relationships between the variables identified in step 2. The model should incorporate the interventions being considered and their potential effects on the key variables.

5. Validate the model: Validate the simulation model by comparing its outputs to real-world data or expert opinions. This step ensures that the model accurately represents the system being simulated.

6. Run simulations: Use the validated model to run simulations under different scenarios, such as varying the coverage and effectiveness of the interventions. This will allow for the assessment of the potential impact of the interventions on maternal health outcomes.

7. Analyze results: Analyze the results of the simulations to determine the potential benefits and limitations of the interventions. Identify any trade-offs or unintended consequences that may arise from implementing the interventions.

8. Communicate findings: Present the findings of the simulation in a clear and concise manner, highlighting the potential impact of the interventions on improving access to maternal health. This information can be used to inform decision-making and policy development.

It is important to note that the methodology described above is a general framework and can be adapted to specific contexts and research questions. The accuracy and reliability of the simulation results will depend on the quality of the data used and the assumptions made in the model.

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