Childhood diarrhea (CHD hereafter) is caused by enteric pathogenic bacteria, viruses, and parasites [1, 2]. CHD remains a major public health threat with nearly 1.7 billion cases occurring annually in the second for 578,000 deaths. CHD spreads from person to person, aggravated by poor personal hygiene  and poor quality of water, sanitation and hygiene that account for 1.7 million deaths, with a significant majority of deaths in developing countries .
Global estimates of deaths from CHD have shown a decline from 2.5 million in 2000 to 1.4 million in 2010  which is still spread all over the world, especially in developing regions such as Africa, South East Asia, and the Eastern Mediterranean, where there is rapid population growth, increased urbanization, limited infrastructures and health system [2, 7]. While mortality rate declined globally but in Africa,the region is seven times higher than that in the European region [8, 9]. Althoughmortality attributed to CHD has decreased significantly over the past 15 years, the morbidity has changed little, but in 2013,578,000 died from CHD , 54% of these deaths were in Sub-Saharan and 25% in Nigeria [11, 12], that the third leading cause of death in children in Ghana.
However, in Ethiopia, annually, CHD kills half a million children next to pneumonia that affected by poor sanitation, shortage of clean water supply and poor personal hygiene, responsible for 90% of CHD occurrence . The 2011 Demographic and Health Survey Ethiopia (EDHS) findings showed that 13% of the children had a CHD in two weeks including South Nation Nationality and People Region (SNNPR) . The proportion of CHD morbidity in Ethiopia is about 22.6% in the different regions with a median of 45%. Similarly, in the northwest parts of Ethiopia, the annual incidence rate was 155.3 per 1,000 populations at risk with varied greatly across the study districts . The previous study in this study area reported that socio economic and environmental factors contributed CHD in Sheko district, Bench Maji Zone, southwest Ethiopia . Additionally this study area is noticed as a CHD hotspot areas due to multiple factors that need due attentions (Fig. 1).
To curve the burden of CHD, improvements in water, sanitation, and hygiene have been considered key public health interventions in low- and middle-income countries . Among various interventions of CHD, handwashing is the simplest and most effective way to prevent diarrhea on under five children . Mainly, hand wash with soap has significant effects on CHDthat reduce by 42–47% .The level of CHD risk is too variable like higher among children whose mothers did not wash hand with soap before food preparation, feeding and after leaving the toilet .Moreover, hygiene interventions, particularly the provision of soap for handwashing, effectively reduce diarrhea morbidity, and there does not appear to be evidence that compliance falls over time.
A study revealed that the prevalence of CHD was 18.3 % that is affected by individual and community level factors, summarized as the following, not washing hands during critical times were 4.6 times risk for CHD while sharing the same residence with domestic animals were 2.87 times more at risk for CHD. Particularly obtaining drinking water from unimproved sources was 2.53 times riskier for CHD. In addition, mothers with limited knowledge about diarrhea were 76% less likely at risk for CHD, and starting supplementary child feeding at age less than six months were 35% less likely risky for CHD . This factor implies multiple interventions are required to prevent CHD with factorial design.
Several interventional studies were done like p-value a cluster randomized control trial in Pakistan on the effectiveness of handwashing promotion in CHD high-risk communities that decreased the incidence of diarrhea by 39% . Similarly,WASH interventions showed CHD reductions between 27% and 53% among children . In another study conducted in Dabat district northwestern Gonder, cluster-randomized control trial on the intervention of SODIS as a water treatment for household, diarrhea incidence decreased 40% . Similarly, at Jijiga district eastern Ethiopia community-based cluster randomized control trial on handwashing with soap and WASH education has decreased the incidence of CHD by 35% . Moreover, mainly household water treatment has been recognized as a cost-effective means of reducing the burden of CHD and other waterborne diseases, especially among populations without access to improved water supplies , where strategies to improve the microbialquality of drinking water can be applied at the source or in the household. Water source includes protected wells, boreholes andpublic tap stands . Whereas household strategies includeimproved water storage or approaches for treating water, such as chlorination,solar disinfection, filtration, or combined flocculation anddisinfection .
Despite the availabilities of few studies on interventions on CHD, there are no or limited evidence of handwashing with soap at a critical time and home-based water treatment at the household level in this study area. Additionally, combination effects the intereventions that aimed to control the prevailing burden of CHD through community randomized control trial(cRCT) also limited. Thus, the cRCT interventional trial was planned to significantly reduce the peaking of CHD in hotspot areas.
The rationale for designing the cRCT intervention is due to the CHD burden prevailing in southwest Ethiopia based on research findings and related empirical evidence . As a result, we have found a high burden (36.1 per 1,000) of CHD with significant variation between the districts in southwest Ethiopia.To respond to the CHD effects, the cRCT is claimed to be used to identify the cause-effect relation between the outcomes and reduced CHD burden. Mainly, avoid any population bias, easier to blind analyzed with well-known statistical tools; populations of participating individuals are identified in-group.
Evidence needed on all potential intervention measurements with handwashing intervention at a critical time, where the intervention households benefited directly with gain health education and soap for handwashing purpose to prevent the incidence of CHD. Since the intervention is simple and costs usefull for all family members, specifically low-income countries like Ethiopia can apply the resultto preventCHD and other communicable diseases. Furthermore, it was used for concerned bodies, policymakers’ executive/implementers and governmental or non-governmental bodies to focus on specific CHD prevention intervention and contribute to the future research hypothesis. Thus, this intervention aimed to evaluate the effectiveness of handwashing with soap at a critical time and home-based water treatment to CHD in hotspot areas of southwestern Ethiopia, 2020.