Effect of Water, Sanitation and Hygiene Educational Intervention on Incidence of Diarrhea and Childhood Stunting Among Under Five Children in Bule Hora Wereda, Southern Ethiopia

hern Ethiopia. Introduction The global burden of childhood malnutrition and diarrhea remains life-threatening, yet these conditions are preventable1,2. Factors contributing to morbidity, mortality, and impaired growth in children under five are particularly high in low- and middle-income countries3. Diarrhea is the second leading cause of child morbidity and mortality worldwide and is responsible for more than 90% of deaths in children under 5 years of age in low and middle-income countries4.

Childhood diarrhea stems from interconnected environmental, host, and socioeconomic determinants where contaminated water and inadequate sanitation perpetuate fecal-oral transmission while nutritional deficiencies including nonexclusive breastfeeding, zinc deficiency, and malnutrition compromise intestinal immunity5. Inadequate water quality, open defecation, poor waste disposal, and insufficient hand hygiene expose children to bacteria, viruses, and parasites. These repeated infections cause acute episodes of diarrhea while simultaneously inducing chronic inflammation of the intestinal mucosa. Persistent intestinal injury disrupts the epithelial barrier, allowing microbial products to translocate into the bloodstream and trigger systemic inflammation6.

As intestinal permeability increases, nutrient digestion and absorption become impaired. Chronic inflammation reduces the absorptive surface area of intestinal villi and increases energy expenditure for immune responses. Consequently, children experience mal-absorption of essential nutrients, micronutrient deficiencies, impaired immune function, and poor physical growth7. Even in the absence of overt diarrhea, chronic exposure to fecal pathogens leads to Environmental Enteric Dysfunction (EED). EED is a subclinical disorder marked by increased intestinal permeability ("leaky gut") and chronic inflammation. This silent pathway continuously impairs nutrient absorption, establishing a direct link between a dirty environment and stunting without presenting visible symptoms of illness8.

Despite a global decline in stunting rates in recent time, Ethiopia continues to report a high prevalence, with national figures revealed that around 39%, and even higher rates in rural, drought-prone districts such as pastoralist communities with poor water supply, sanitation and hygiene (WASH) conditions9. Water supply, sanitation, and hygiene interventions are among the most effective measures to protect against diarrhea and stunting10. Behaviors that encourage human contact with fecal matter include: improper disposal of feces; children defecating on the floor; rags being used to cleanse the child open defecation; and lack of hand washing open defecation, handling feces (including children's feces) or cleansing the child's perineum and before handling food by caregivers and children11. WASH interventions may be effectively promoted using culture- and context-specific behavior change strategies.

There are no "silver bullets" that apply to all settings equally, and each setting requires a unique intervention approach when implementing WASH education packages12. Noticeably, in agro-pastoral and pastoralist communities in southern Ethiopia, infants and young children regularly contact with livestock and their feces, and this poses a constant health risk. In West Guji zone, the prevalence of diarrhea among children less than two years of age was found to be as high as 36.5%, while maternal educational status, waste disposal method are major factors significantly associated with childhood diarrhea in this setting13. Evidence-based and context-specific behavioral interventions that can impact community-level knowledge, perceptions, and practices are required to effectively implement the WASH components.

Therefore, this cluster-randomized controlled trial aims to evaluate the impact of a comprehensive, behavioral change-focused WASH education intervention on the incidence of diarrhea and stunting among children under five, thereby providing crucial evidence on the efficacy of such targeted approaches in high-risk agro-pastoral and pastoralist communities.

Method and Materials Study area and period The study was conducted in Bule Hora Woreda, West Guji zone, Southern Ethiopia from November 1, 2024 - April 30, 2025. Bule Hora Woreda is one of the 10 Woredas found in west Guji zone, Oromia regional state of Ethiopia. Annual rainfall of the area ranges between 801mm to 1000mm which is high monthly (i.e. May, Jun July, August and September) and is followed by long dry season (November, December, January, February and sometimes to March and May13. The area is a rapidly developing area characterized by a mix of agricultural and urban livelihoods, while livestock production is one of the economic activities in Bule Hora Woreda. The population of the area was estimated to be over 393,000 as of 2022, with approximately 9,990 births in the past year14.

Study design A cluster randomized controlled trial was used to determine the effect of WASH education intervention on incidence diarrhea and childhood stunting among children less than five years old in Bule Hora Woreda, West Guji zone Southern Ethiopia.

Sample size determination Sample size calculation was based on the primary outcome by using the method published by Hayes and Bennett16, and thus by taking 35% reduction in incidence of diarrhea from a recent study conducted in Eastern Ethiopia17. Using this incidence, along with 80% power and 95% confidence interval (α = 0.05), and considering a Mancl DeRouen correction, the final sample of 26 clusters (13 for the intervention group and 13 for the control group) was randomly selected and included in the study.

Assumptions:

• Baseline incidence rate = 36.5%18.
• Intra-cluster correlation coefficient = 0.2219.
• Average cluster size = 28 participants, by considering data collection cost.
• Follow-up duration = 6 months (26 weeks) Randomization and Masking From 6 districts that originally organized by the Bule Hora woreda health office for the ease of health service program implementation, 2 districts were randomly selected. Accordingly, Garba district containing 10 kebeles ((54 sub-kebeles)), which is found at the north direction from the Bule Hora town, and the Berdaye district containing 9 kebeles (47 sub-kebeles) that found at the southern direction from the Bule Hora town was selected to include in the study. Besides, from each of the north and south districts 3 kebeles (that accounts 30% of the total kebeles in each cluster) was randomly selected. The selected kebele was further divided in to sub-kebelles (neighbourhood villages). Finally, 26 Sub-kebeles (Clusters), 13 from Gerba district in the north direction and 13 from Berdaye district in the south direction were selected randomly and assigned to the intervention and control group respectively (Figure 1). Data collectors and outcome assessors were blinded to group allocation. Participants could not be blinded due to the nature of the educational intervention, but field workers delivering the intervention were not involved in outcome assessment. The follow up study was takes six months to observe the effects of WASH on incidence of children and stunting under-five in the study area.

Figure 1 CONSORT flow diagram. Intervention A health education on key hygiene and environmental sanitation components of Ethiopian health extension program20, and demonstration of hand washing with soap were given to all of the intervention clusters by graduate class environmental health science students of Bule Hora University, during their attachment at the study site and health extension workers (field workers) who have taken training for 5 days.

Primary care takers of the children in the households were instructed to keep their water storage container clean and covered, to have a latrine and utilize properly, and to wash their hands and children's hands ideally with soap after defecation, before meal preparation and eating. Intervention happened every 2 weeks in a period of 6 months follow up. All interventions were delivered as planned. All households in the intervention clusters received a package of health education messages (Table 1) bi-monthly for 6 months. Each intervention took up to 3-hour time from 8:30 am to 11:30 am local time since most village residents were available in the morning time. The field workers demonstrated by face to face approach how to wash their hands with soap and rub together for 1 min. Moreover, field workers was encourage the intervention group by promoting of using latrines for defecation, removal of human and animal waste from the household area, and safe disposal of children's faeces, and household water treatment and safe storage practices to prevent diseases. Primary caretakers of the control group continued their usual way of hand washing practices, disposal of water storage behaviour and latrine sanitation and did not receive any intervention.

Data collection and Outcome assessment A baseline survey of socio-demographic factors, prevalence of childhood stunting, diarrhea, and WASH related factors was conducted on primary care takers, children and household by using face-to-face- interview questionnaire after enrolment.

Ten data collectors (field workers) and two supervisors were visited intervention and control households for a baseline and end line assessment. The primary outcome was incidence of diarrhea at every 2 weeks period and along with secondary outcome of childhood stunting; that was measured by mean height for age Z score (HFA z-score) to detect the improvement in child growth. Anthropometric measurement (height/length of the children) was collected using a measuring board with a headboard and sliding foot piece for length and a Stadio meter to measure height, following the procedure stipulated by the World Health Organization/ United Nations Children's Fund21,22.

Moreover, primary care takers were instructed to follow the child and report incidence of diarrhea in the previous two weeks. One health extension workers from each cluster was recruited and trained to collect information on the longitudinal incidence of diarrhea. These health extension workers visited each enrolled household every 2 weeks for 6 months after baseline. The bi-monthly report included information on any episodes of diarrhea for each under five child of the household.

Operational definitions

• Childhood stunting is defined as children below minus two standard deviations (-2 SD) of height for age Z-score in the reference population23.
• Diarrhea is defined as the passage of three or more liquid or semi-liquid stools in a 24-hour period or the passage of at least one liquid or semi-liquid stool with blood or mucus24.
• Kebelle is the lowest administrative unit in Ethiopia holding with the maximum numbers of 500 households, or the equivalent of 3,500 to 4,000 persons25.
• Improved drinking water sources: water sources that are designed to protect against contamination, which include piped water, boreholes or tube wells, protected dug wells, protected springs, and packaged or delivered water.
• Unimproved drinking water sources: water source from unprotected wells, unprotected springs, or surface water.
• Improved sanitation facilities: sanitation facilities that are designed to hygienically separate excreta from human contact such as flush/pour-flush toilet ventilated improved pit latrines, composting toilets, and pit latrines that have a slab or platform.
• Unimproved sanitation facilities: sanitation facilities that include pit latrines without a slab or platform, hanging latrines, and bucket latrines26.
• Adequate Dietary Diversity Score: It is the proportion of infants and young children aged 6-59 months who received foods and drinks from 5 and more out of 10 food groups in the previous 24 hrs. Consumption of any amount and quality of food from each food group was sufficient to "count"17,27.

Data processing and analysis Prior to data entry, base line and follow up visit of data forms was checked by the field supervisors for completeness and consistence. Data was double entered on to Epi-Data Version 4.2 and statistical analysis was performed by using SPSS version 25. Intention-to-treat analysis was used to compare the incidence of diarrhea among under-five children between intervention and control groups.

The baseline data was analysed and compared among the intervention and control group. The rate of diarrhea (per 100 person-weeks) in children under-five years of age was measured for the intervention and control groups. Generalized estimating equation with log link Poisson distribution family was used to compute adjusted incidence rate ratio and the corresponding 95% confidence interval of the dependent variable (longitudinal incidence of diarrhea) and covariates. Potential confounding variables (child age, child sex, and the number of under-five children, mother age and sex, type of water source, point-use water treatment and category of sanitation) are adjusted by including them as covariates in the marginal mean model. For the prevalence of stunting, Emergency Nutrition Assessment (ENA) for Standardizing Monitoring and Assessment of Relief and Transition 2011 software was used to convert raw anthropometric data into Z-scores, and compared among the intervention and control groups.

Data Quality assurances The data quality was assured by pre-testing 5% of the baseline data collection tool before the actual survey in Dugda Dawa Woreda. The data was collected by trained enumerators who spoke the local dialect. To ensure validity and reliability, the field teams was verify the proper functioning and calibration of the measurement instruments before the commencement of fieldwork and on a daily basis before starting their activities. Supervisors checked the proper implementation of the education sessions and data collection. Moreover, on spot checks was also incorporated in the process that including: minimizing clothing on the child, ensuring the scale is not over-heated in the sun and is placed on an even surface, and calibration checks conducted for the scale after each household.

Ethical statement Ethical clearance was obtained from Bule Hora University (Ref.No: BHU/IOH/IRERC/017/25). Verbal informed consent was obtained from all participating households after explaining the study purpose, procedures, risks, and benefits. For community-level agreement, verbal consent was also obtained from Woreda administration and community leaders. Participants were informed of their right to withdraw at any time without penalty.