A systematic review of water, sanitation, and hygiene practices in developing countries: exploring the effects on public health

Abstract

BACKGROUND: Lack of proper access to safe Water, Sanitation, and Hygiene (WASH) is a pervasive cause of preventable disease and mortality in developing countries, disproportionately impacting the most vulnerable portions of the population. Despite activity globally, much still needs to be accomplished regarding expansion of WASH coverage, and the issue still remains a defining public health challenge. This systematic review synthesizes available evidence to assess the current status of WASH practices, associated health outcomes, and the barriers to effective safe WASH behaviors in developing countries. . METHOD: The systematic review examined WASH practice and access conditions in the developing world. Of a total of 1273 records identified via Google Scholar, Scopus, MEDLINE, Embase, and PubMed, 44 studies were incorporated that meet the inclusion criteria through a rigorous screening process according to PRISMA guidelines. Quality of studies was assessed using the Cochrane Risk of Bias tool (RoB 2), and reviewed by three authors. RoB 2 tool was applied using five primary domains randomization, deviation from interventions, missing data, outcome measurement, and selective reporting to critically assess the methodological quality of included studies. RESULTS: According to the reviewed papers, approximately 73% of the study focused on children and newborns under the age of five, indicating their high prevalence of WASH-related illnesses. Up to 69% of households do not treat their drinking water and only one-third of caregivers practice consistent handwashing at important periods. In children aged 6-23 months, soap-based handwashing significantly lowers diarrhea and respiratory illnesses. Access to clean and safe water remains limited, with just 16-50% of populations in some countries (e.g., Bangladesh, Tanzania, Ethiopia, and Chad) having sufficient access. Improved water sources are frequently available, although household-level treatment and storage remain low (4.7%-34% in rural areas). Water availability is heavily influenced by socioeconomic factors such as income, female education, and political stability. Several countries (e.g., Nigeria, Bangladesh, Ethiopia, Kenya, and India) have low sanitation coverage, whereas others (China and South Africa) do better. Improved sanitation facilities limit pathogen exposure, improve child nutrition by reducing intestinal infections, and increase economic and environmental sustainability. CONCLUSION: The evaluated research shows that WASH-related illnesses disproportionately impact children under the age of five, who make up roughly three-quarters of the study population. Despite progress in upgrading water sources, access to safe and clean water remains extremely limited, particularly in low-income and politically insecure areas. Household water purification and safe storage methods are woefully inadequate, leaving households vulnerable to preventable infections.