Latrine surface contamination and hygiene practices in rural Nepal: implications for diarrhoeal diseases and urinary tract infections

Conceptual diagram linking faecal contamination in pour-flush latrines to pathogen exposure through hands, anal cleansing water containers, and footwears, with risk of faecal-oral, urinary tract, and soil-transmitted helminths infection. Microbial contamination from faeces to hands after latrine usage significantly increases the transmission risks of faecal–oral infections. This is further exacerbated in regions using water-based anal cleansing and without adequate handwashing facilities. In Nepal, understanding latrine surface contamination is crucial as diseases such as typhoid and cholera are endemic, and 36% of the population lacks access to basic handwashing facilities. This study aims to assess latrine usage behaviours and faecal contamination levels (Escherichia coli) on frequently contacted household latrine surfaces of Ichchhakamana Rural Municipality, Chitwan. It includes analysis of the National Water, Sanitation, and Hygiene survey (n = 628) and latrine swab samples (n = 91) from eight latrines. E. coli densities on latrine surfaces were significantly associated with flush types, latrine location, and visible moisture and dirt. Households reporting diarrhoea had significantly higher E. coli on latrine surfaces (2.6 × 102 CFU/25 cm2) than those without (12.3 CFU/25 cm2) (p < 0.001), suggesting a possible diarrhoeal transmission pathway. It also highlights the potential risk of urinary tract infections, specifically for women from faecally contaminated anal cleansing water. Despite having improved sanitation infrastructures, findings emphasise the need for context-appropriate interventions that prioritise latrine cleanliness and safe hygiene to reduce pathogen transmission from latrines.