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The Global Handwashing Partnership

Focusing on the H in WASH: New Insights into Why Handwashing and Hygiene are Key for Child Health and Growth

April 8, 2019

Editor’s Note: This post is an installment in our Ask the GHP series.

By: Julia Rosenbaum, FHI 360

As handwashing advocates and programming implementers, we work to ensure that attention and funding go to the neglected ‘H’ in WASH, to handwashing and hygiene. However, we know that handwashing alone will not ensure the health and other gains we seek. A recent review provides a new perspective on one key set of practices that may need to be addressed alongside handwashing.

Emerging evidence and analysis suggest that household hygiene may play a much larger role in the growth of infants and young children that previously established. But unfortunately, the implications for hygiene programming aren’t yet too clear. In this post I review what we know so far, what we don’t know, and how we can begin to incorporate household hygiene into WASH work.

Why does stunting persist? What we know so far

Despite decades of nutrition and integrated interventions, about one quarter of children under age five are stunted, with the vast majority living in low- and middle-income countries. (UNICEF, WHO, & World Bank 2015). Inadequate diet and poor water, sanitation, and hygiene (WASH) conditions predispose infants and young children to a debilitating cycle of infections and undernutrition in early life. Stunting is not only low height for age, but also brings cognitive and developmental stunting affecting learning and earning potential later in life; and perpetuating cycles of poverty and misery.

But mounting evidence may shed light on why child growth stunting persists, even with comprehensive WASH and nutrition programming. Chronic exposure of infants to high loads of fecal microbes has been hypothesized to be a significant underlying cause of child growth faltering. This exposure causes environmental enteric dysfunction (EED), a condition where the lining of the small intestine becomes inflamed. EED shows that constant fecal assault on the gut of infants changes the shape and function of the intestine, making it harder to absorb much needed nutrients, and setting an infant’s body into overdrive to try and resist all the filth and infection. EED is thought to explain why even the most rigorous and comprehensive dietary interventions have only a modest effect on reducing child stunting.

Notably, EED and subsequent stunting can happening independent of the effects of diarrhea, so that an infant without symptoms may still suffer from EED. Risk has often been assessed using diarrhea as the primary outcome, potentially missing the key link between various exposures or interventions and growth. For nearly six decades, WASH interventions have been guided by a seminal “F-diagram”, which traces how uncontained feces work their way into water and food via fluids, fingers, flies, fields (floors, earth, dirt), fomites (surfaces) (Wagner & Lanoix, 1958). WASH interventions traditionally focused on “blocking” these transmission pathways through increasing access to an improved water supply, improving drinking water quality, and refining hand hygiene and sanitation measures.

But for infants and young children, the classic F diagram misses some key sources of fecal exposure, as well as pathways of transmission.

The USAID Water, Sanitation, and Hygiene Partnerships and Learning for Sustainability (WASHPaLS) project conducted a review of the scientific and gray literature, to synthesize the latest understanding of key pathways of fecal microbe ingestion specifically affecting infants and young children (IYC), the relative potential importance of the various pathways in terms of magnitude of pathogen transmission, and how to best mitigate them. The review included 160 articles, and was complemented by dozens of key informant interviews with researchers and field implementers. The full text of the review can be accessed here.

What is New? Key Findings on Neglected Sources and Pathways of Transmission

Domestic animal waste: The abundance of uncontained animal feces in developing countries is an important and historically underemphasized source of pathogens and fecal microbes in the domestic environment and water supply sources. Domestic animal husbandry is common among rural populations, and multiple studies document significant sources of animal fecal contamination in the domestic environment, including both poultry and ruminants, spanning South Asia, East Africa, and South America. However, animals also bring nutritional benefits from increased food access as well as the increased household income. The data are inconclusive about the overall impact when positive and negative are weighed.

The ingestion of soil (geophagy) and mouthing of household objects: Infants and young children ingest dirt and feces through exploratory mouthing of soiled fingers, toys, and household items as well as by directly ingesting contaminated soil and/or feces. Babies learn about their world by putting almost everything that they can reach into their mouths, and this exploratory mouthing also assists cognitive and motor development and provides comfort. Soil ingestion among IYC has been widely observed and associated with increased risk of both disease (diarrhea and worm infection) and growth faltering.

Unsafe disposal of infants and young children’s feces: The highest levels of unsafe child feces disposal are found among poor, rural households; among the youngest children; and where other household members were practicing open defecation. However, unsafe practices are found even in households with improved sanitation. Unsafe management of child feces is linked with growth faltering and higher odds of detecting E. coli in areas where children play.

Based on existing evidence, we suggest that traditional WASH measures aren’t enough to address the exploratory mouthing behaviors that are a key part of early childhood development, nor to address exposure to domestic animal feces.

So, what then, are appropriate measures?

As advocates and evidence-based implementers, we need to beat the drum to get more attention towards a hygienic environment for infants and young children. But current evidence doesn’t yet suggest a clear programmatic pathway forward.

A revisioning of the F diagram illustrating sources of exposure to fecal pathogens, transmission pathways, and measures to block transmission

Emerging Interventions

Our review identified 17 service delivery programs employing measures that fall within the scope of protecting infants and young children from exposure to feces. These included the distribution or sale of playmats and playpens and promotion of behavior change interventions directed at corralling animals away from children and generally keeping courtyards clean. Several researchers have also turned their sights to the effect of various products and behaviors at reducing exposure. Current interventions fall into three general categories:

Barriers: Efforts have been made to construct barriers to keep animal feces out of the home environment, and to prevent associated ingestion of soil and animal feces. These barriers include finished flooring; improved animal husbandry practices; playmats for immobile infants; and a playmat/playpen combination for crawling and mobile infants.

Animal Feces Management: Interventions to protect infants and young children from pathogens in animal feces have focused generally on day- and/or nighttime separation of children and animals, improved corralling, and courtyard cleaning.

Safe Disposal of Child Excreta: Existing interventions promote the safe disposal of feces using approaches ranging from general “safe disposal” messaging to age cohort-specific behavioral programming targeting feasible but improved disposal practices, such as locally-crafted reusable diapers, sani-scoops, potties, and child-friendly latrines.

Assessing the true potential of these interventions requires a better understanding of the behavioral feasibility of the intervention, as well as the biological plausibility or effectiveness. To date, we know little about thresholds of exposure as they affect disease and child growth. For instance, if an infant is placed in a playpen instead of on the ground for four full hours in the day, but then comes out, crawls to her father’s cast-off gumboot and starts mouthing the shoe, did those four hours help at all?

As with any behavior-centered programming, we also need to better understand the behavioral feasibility of the practice. Cooping chickens during the day time may not be feasible given the dependence on free-range feeding and preference for meaty yard hens, for instance. Do households consider the proposed behaviors feasible and appealing?

Likewise, current interventions to protect infants and young children from exposure to pathogens found in animal feces focus on disposal of animal feces, when in fact many households value these feces as fertilizer, fuel and building material. Additional research is required to explore the safe management of productive feces in the household.

Beyond behavioral feasibility and effectiveness, additional research is also needed to investigate the adoption, constraints, and scale-up potential of these and other measures to reduce exposure to fecal pathogens. Researchers are starting to address these questions from a variety of angles and will provide much needed data to guide programming.

What does this mean for handwashing and hygiene advocates?

It is well documented that infants and young children will go hand to mouth with soiled objects, suck on their fingers, eat handfuls of contaminated dirt and even chunks of poultry excreta. However, we don’t have consensus on whether it is behaviorally feasible or biologically effective to promote handwashing for infants and young children. Damp hands will pick up more dirt, that will then be licked off; drying is often done with contaminated towels or clothing that may introduce more pathogens than washing eliminates. At the same time, in addition to reducing pathogens on hands, washing the hands of infants and young children gives an early start to handwashing habits throughout life, and sets a clear social norm. Despite a lack of clear consensus, most BabyWASH activities include periodic washing of young children’s hands, particularly before feeding.

The emerging research clearly points to the need to address the neglected pathways and focus on assuring a more hygienic environment. This shift to more comprehensively addressing the environment cannot be underestimated if we are to begin to address these neglected sources and pathways. We know that clean hands are important but not sufficient, and we are learning more about what is required to establish and maintain an environment where children can explore and develop without the devastating consequences of sickness and stunting. Monitoring a child’s environment, clearing areas of visible feces, taking action when the child reaches for dirt and feces, maintaining the cleanliness of toys and any object within reach of the child, and other measures are all essential components of such a hygienic environment.

About the Author: Julia Rosenbaum is a seasoned health behavior specialist with FHI 360. She has played a key leadership role in integrating WASH into HIV, nutrition and education programming; developing key documents with USAID, WHO and UNICEF as well as pioneering country-level programming. She is co-developer of the BEHAVE Framework for Program Planning (now adapted and rebranded as Designing for Behavior Change) which has been widely applied by hundreds of government and non-governmental organizations in planning evidence-based behavior change initiatives. Currently, Rosenbaum serves as Senior Behavior Change Specialist for the USAID-funded WASHPaLs Project, where she leads a task exploring Hygienic Play Spaces for Children, to build evidence-based programming guidance around the neglected pathways of the “F-Diagram”. Julia has been involved with the Global Handwashing Partnership and its predecessor PPPHW for more than a decade, and currently serves on the GHP Steering Committee. She holds an ScM from the Harvard School of Public Health and an undergraduate degree form the University of Michigan in Medical Anthropology.

Learn more about #AsktheGHP here. To submit a question, e-mail the Global Handwashing Partnership Secretariat at or use #AsktheGHP on social media.

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