The study was conducted in Thankre VDC, Dhading District, Nepal, a remote hilly area with altitudes ranging from lowlands to high hills. The term “Village Development Committee (VDC)” refers not only to the administrative committee but also to the area it governs. Thankre VDC comprises nine wards, which, at the time of the study, included a total of 2,141 households (9,838 people) [3]. According to the District Drinking Water and Sanitation Division Office (DWSO), toilet coverage in the VDC was estimated at 19.6%, the lowest in the region. In addition, nearly 45% of the VDC population belonged to various ethnic communities, including Tamangs, Chepangs, Dalits (scheduled castes), and others [11]. Thankre VDC was purposively selected from the 50 VDCs in Dhading District because it had the lowest sanitation coverage in the southern region, highlighting the highest need for improved access to sanitation and hygiene practices.

The study population consisted of alliance members and household representatives. “Alliance member” refers to individuals representing local organizations or the community, selected by consensus within the alliance. These members included the VDC secretary, health post and sub-health post in-charges, NGO representatives working in the VDC, local school teachers, community leaders such as Female Community Health Volunteers (FCHVs), and local politicians. Alliance members were required to be at least 20 years old and willing to partici pate; those unable to read or write in Nepali were excluded.

“Household representative” refers to a male or female recognized by their household as the head or designated representative. Eligible participants were at least 18 years old, had lived in the community for more than six months, and were willing to participate. Exclusion criteria included inability to communicate verbally, temporary household membership, and age above 80 years.

The total sample size was calculated using the formula for repeated measures [20]. Mean scores for access to sanitation and basic knowledge of sanitation and hygiene were obtained from a pilot study conducted in another VDC within the same district. It was projected that the intervention would lead to a 50% increase in the mean scores of these variables between baseline and post-intervention. The required sample size for a single group was calculated as 183 households. Since this study employed a pre-test–post-test design, the number was doubled. An additional 10% was added to account for potential household dropout, resulting in a final minimum required sample size of 402 households.

The instruments used in this study were translated into Nepali and pre-tested with respondents from a nearby, similar household before data collection. Data were collected by the principal investigator and seven trained research assistants, all of whom had experience in community health and development work.

The pre-alliance self-assessment questionnaire for alliance members consisted of three parts. Part I included demographic information, such as sex, age, and educational level. Part II assessed basic knowledge of sanitation and hygiene and comprised 16 items with statements answered as “yes,” “no,” or “don’t know.” The Cronbach’s alpha coefficient for this section was 0.690. Part III evaluated basic management competencies with 16 items, featuring a combination of response types, including single-response ordinal scale, multiple responses, and multiple-choice questions.

The closed-ended interview questionnaire for household respondents also comprised three parts. Part I contained seven items regarding general household and respondent characteristics, such as sex, age, and type of house. Part II included 23 items assessing basic knowledge of sanitation and hygiene. Respondents self-reported diarrhea symptoms in accordance with the WHO definition [21], with a Cronbach’s alpha coefficient of 0.682. Part III focused on hand-washing practices and diarrhea prevalence, containing four items with single and multiple-response formats.

The observational checklist had two parts. The checklist included yes/no or other related options for each item. Items were ticked after direct observation and/or confirmation by the household respondents.

Part I was on the availability and sanitary use of improved toilets and had 10 items. Part II was on practices related to the disposal of domestic waste and wastewater, disposal of domestic animal waste, and the safety of drinking water, and had 14 items with nominal scales. The total score for Part II was 14 for 14 items.

The total score for hygiene practices was calculated by summing the scores for basic knowledge of sanitation and hygiene, handwashing practices, household waste management, wastewater and domestic animal waste disposal, and the safety of drinking water at the point of use.

For qualitative data, semi-structured interview guidelines were employed to interview eighteen alliance members to collect additional information on management competency and knowledge of sanitation and hygiene. Semi-structured interviews were also conducted with twenty-five key household informants, selected from the 492 household respondents, to gather supplementary data on access to sanitation, basic knowledge of sanitation and hygiene practices, prevalence of diarrhea, and other study variables. The semi-structured interviews with alliance members and household respondents were conducted by the principal investigator. Observation data were collected by the principal investigator and seven trained research assistants, all experienced in community health and development work.

Descriptive statistics were used to summarise all study variables and outcome measures. A paired t-test was applied to compare the management capacity of alliance members. Friedman's test was used to compare access to sanitation, basic knowledge of sanitation and hygiene, and hygiene practices among household respondents. In post-hoc analysis, Fisher's Least Significant Difference (LSD) test was used for pairwise comparisons to determine which ranges of access to sanitation, basic knowledge of sanitation and hygiene, and hygiene practices differed significantly. The chi-square test was employed to compare the prevalence of diarrhea before and nine months after the intervention. The significance level was set at α = 0.05. Qualitative data from semi-structured interviews and observations were analysed using content analysis and triangulation techniques.

This mixed-methods study, which combined qualitative research with a one-group pre-test–post-test design, received ethical approval from the Ethical Review Committee of the Faculty of Public Health, Mahidol University, Thailand (COA No. MUPH 2013-116), and the Nepal Health Research Council, Kathmandu, Nepal (Ref. No. 2013-1469). Prior informed consent was obtained from all alliance members and household respondents aged 18 years and above after explaining the study objectives. Confidentiality of the data was strictly maintained. All research activities adhered to the approved protocol and the ethical guidelines of the Ethical Review Committee of the Faculty of Public Health, Mahidol University, Thailand.

The conceptual framework (Fig. 1) consisted of three steps.

Step 1: Preparation (three months)

1.1). Situation Assessment: Including identifying key stakeholders, such as representatives of local organizations, community group leaders, local schoolteachers, and local politicians.

1.2). Formation of the Alliance: Recruiting 18 members in the community to the alliance.

1.3): Baseline Measurement of the Study Variables: In the first month, a self-administered assessment questionnaire was used to assess the management capacity of the alliance members, and a semi-structured interview was conducted with four key alliance members to get qualitative data to complement the quantitative data. There was also a collection of household representative data regarding access to sanitation, basic knowledge of sanitation and hygiene, and hygiene practices. Prevalence of diarrhea from the 2012 Annual report, Department of Health Services [22]. In this study, diarrhea was defined as “the passage of 3 or more times of loose or liquid stools per day, or more frequently than normal for the individual” [21].

Step 2: Implementation (six months).

2.1) An Action Research Approach: The following activities were undertaken to strengthen the management capacity of the alliance members: 1) One-day workshop on sanitation and hygiene; 2) Two-day workshop on the management functions of the sanitation and hygiene project; 3) Action planning for the first phase of the project; 4) Exposure visit to Muralibhanjyang VDC in the same district to observe an a successful sanitation and hygiene project; 5) Visit review to apply learning to the project context; 6) Appreciative inquiry workshop to improve the motivation and positive thinking of the alliance.

2.2) Planning for the Sanitation and Hygiene Project. The planning workshop included: Analysis of the sanitation and hygiene situation in the VDC, stakeholders’ analysis, development of the project objectives and activities, formulation of an action plan, identification of resources, and definition of the roles of alliance members.

2.3) Implementation of the Sanitation and Hygiene Project: The key implementation roles the alliance played were: 1) Communication and coordination within the alliance and with the community; 2) Mobilization of FCHVs, sub-health post staff, and Ward Water Sanitation and Hygiene Coordination Committee for the sensitization of Mothers Groups; 3) Support for sanitation and hygiene awareness activities; 4) Organization of material and technical support to the households who built toilets; 5) Decision-making on important implementation issues; 6) Review of, reporting on, and monitoring of implementation; 7) Building of relationships with the District Drinking Water and Sanitation Division Office and the District Development Committee to obtain resources for the project.

2.4) Monitoring: The alliance periodically reviewed project implementation, conducted monitoring visits to communities, and submitted periodic progress reports to the Drinking Water and Sanitation Division Office and the alliance-facilitating organization.

2.5). Evaluation: After six months of implementation, the first evaluation of the study variables was done. The alliance made a decision for the evaluation. At this stage, the alliance also consolidated the lessons learnt from the alliance processes.

Step 3 Reinforcement (three months)

After six months of implementation, the project progress was reviewed. Following this review, the project placed greater focus on achieving Open Defecation Free (ODF) status in all nine wards of Thankre VDC within three to four months. This enhanced focus included: 1) continuing health awareness activities in community groups and schools; 2) frequent monitoring by the Ward Water, Sanitation, and Hygiene Coordination Committee; 3) providing material and technical support to households for toilet construction; 4) motivating households that had been resistant to the campaign; and 5) addressing key project management challenges, such as shortages of materials in the market.

A one-day workshop, attended by alliance members and representatives from the lead agency, was conducted to review the project processes, assess project progress, identify strengths and weaknesses, and summarise lessons learned by the alliance.

The final evaluation involved measuring the management capacity of the alliance members, households’ access to sanitation and hygiene, and the prevalence of diarrhea among household members. Semi-structured interviews were also conducted with 25 household representatives to explore additional issues related to sanitation and hygiene practices. Preliminary findings from the evaluation were shared during an alliance review meeting and used to identify strategies for improving the project in subsequent months.

Table 2 shows that six months after implementing the model, the overall mean score for management capacity of the alliance members increased significantly (p < 0.001). Both sub-domains, basic knowledge of sanitation and hygiene, and basic management function competencies, also showed significant improvement (p < 0.001).

Table 3 presents the changes in management capacity by level. The number of alliance members with a “high” level of management capacity increased from 4 at baseline to 10 after six months. No members remained at a “poor” level, and all members attained a “high” level of basic knowledge of sanitation and hygiene. Basic management function competencies increased from 1 member to 5 at a “high” level and from 11 to 13 at a “moderate” level.

Table 4 shows that six months after implementing the model, the overall median score for household access to sanitation increased significantly, from a baseline median of 0 (range 0–8) to a median of 7 (range 0–8) after nine months of implementation (p < 0.001). Similarly, basic knowledge of sanitation and hygiene improved significantly, from a total score of 14 (out of 22) at baseline to 19 after nine months (p < 0.001). Hygiene practice scores also increased significantly, from 7 (out of 19) at baseline to 11 after nine months (p < 0.001).

In post-hoc analysis, Fisher's Least Significant Difference (LSD) test was used for pairwise comparisons of access to sanitation, basic knowledge of sanitation and hygiene, and hygiene practices. Table 4 further shows that access to sanitation before implementation and after six months differed significantly (p < 0.001) from scores at nine months. Basic knowledge of sanitation and hygiene at baseline differed significantly (p < 0.001) from both six-month and nine-month scores, while the six-month score also differed from nine months (p < 0.001). Similarly, hygiene practices at baseline were significantly lower (p < 0.001) than at six and nine months, and scores at six months were also significantly different from those at nine months (p < 0.001).

Table 5 presents household access to sanitation and knowledge/practice levels. The proportion of households with “high” access to sanitation increased from 30.1% at baseline to 60.6% at nine months. Households with no access decreased from 55.7% at baseline to 27.2% at nine months. The proportion of household representatives with “good” basic knowledge of sanitation and hygiene rose from 0% at baseline to 75.0% at nine months, while those with “poor” knowledge decreased from 74.6% to 0.0%. Similarly, households with “poor” hygiene practices declined from 74.6% at baseline to 27.2% after nine months.

Table 6 shows a significant decrease in the prevalence of diarrhea among children under five years of age after six and nine months of implementation (p < 0.05). Similarly, the prevalence of diarrhea among individuals aged five years and above also decreased significantly. Overall, the prevalence of diarrhea across all age groups decreased by 18.5% at six months and by 67.4% at nine months.

The key lessons learned, along with other factors contributing to the success of the project, such as the socio-cultural and political context, government policies, and support from organizations, can be used to improve future sanitation and hygiene projects and action plans (Fig. 2) [23]. The alliance model may also be applied in other developing areas or countries.

The capacity building intervention was useful and exciting part of the project that made alliance members actively involved in the sanitation and hygiene project. In addition, their continuous involvement in planning, implementing, and monitoring of the project contributed to improving their management capacity. The clearly defined common goal and action plan gave them a direction and framework for involvement, which was helpful to unite them. The alliance was formed with the leadership of the VDC secretary who was the acting chair for the VDC which was the local government authority to oversee the development and administrative functions. The alliance was able to mobilize a large number of resources from different stakeholders. The alliance was effective in building a good level of trust among the project stakeholders which was lacking at the beginning due to the socio-political and cultural context of the VDC.

Our findings are similar to a report from a study in two districts in northern Karnataka, India [26], which improved the capacity of the Village Health and Sanitation Committee (VHSC), a local body involving stakeholders for planning and monitoring health and sanitation activities. Evaluation of the two-year program outcomes showed significant improvements in members' participation, provider-community interactions, and VHSC meetings. The action research intervention in our study increased the effectiveness of alliance members in implementing, managing, and sustaining the sanitation and hygiene project.

The current study has some limitations. The purposive selection of Thankre VDC, due to its lowest sanitation coverage, may introduce selection bias. Future research should involve a larger number of participants and include a control group to establish stronger evidence. In addition, the validity and reliability of diarrhea prevalence also rely on self-reports from household respondents and information from the Department of Health Services of Nepal. However, diarrhea is a common disease, and most household respondents were familiar with its symptoms, so this may cause only minor errors.

The decrease in diarrhea cases among children under 5 years was marginally significant. However, there were highly significant decreases in diarrhea for the overall population and for individuals above 5 years of age. Possible explanations include the fact that early childhood diarrhea is caused by multiple factors, such as children’s nutritional status, access to water and sanitation [9], caregivers’ hygiene practices [27, 28], and climate factors [29]. From the household survey, we found that several poorer households lacked soap, coal ash, or other local cleaning agents for handwashing, could not afford a water purification system, and kept domestic animals at home. These factors can contribute to childhood diarrhea. A study in Laos PDR [28] found that children in households with handwashing facilities, including both water and soap, were less likely to contract diarrhea compared to households with water alone. Adults may improve their hygienic practices more effectively after a behavior change campaign than children under 5 years, which may explain the higher number of diarrhea cases in this age group.

Sustainability is a broad concept, and its definition and indicators depend on which aspects of sustainability are being focused on [17]. Various concepts of sustainability exist from different perspectives, focusing on the environment, communities, or project planning [30-33]. In this study, sustainability refers to the long-term expected impact on the management of the sanitation and hygiene project as a result of applying the healthy alliance. Several key indicators were identified at the end of the study that may contribute to the project’s sustainability.

There was a functional alliance under the leadership of the VDC Secretary at the VDC. The study showed that their project management capacity had improved significantly. They had clearly defined project goals and basic management capacity to prepare the next phase plan involving all stakeholders. They also demonstrated competencies in fundamental management functions. A capable alliance has greater potential to continue the project in the future.

The alliance implemented the project by involving all stakeholders and community members. Every sector of the community participated in the project in different ways, creating momentum for the initiative. This participatory approach has been established as part of the project.

The alliance was able to mobilize a large number of resources, including funds from different stakeholders. Partnerships and networks were established with key stakeholders, and local resources were effectively mobilized. Therefore, the alliance now has the network, capacity, and experience to secure the resources required to continue the project in the future.

According to government policy, the local VDC is responsible for leading sanitation and hygiene projects. The alliance was established under the leadership of the VDC, and all project plans were submitted to the VDC Council, the supreme body responsible for policy formation and budget allocation. The VDC has prioritised the sanitation and hygiene project, allocating increased budgets over the last two years, making it a regular and prioritized part of the VDC’s activities.

These key indicators suggest that the sanitation and hygiene project has potential for future sustainability and for achieving its goals and objectives.