Comparing the Effectiveness of Shared versus Private Latrines in Preventing Trachoma in Rural Tanzania

Sharing latrines is common in sub-Saharan Africa with anecdotal accounts suggesting a link between water-, sanitation-, and hygiene-related disease and poorly maintained communal latrines. This study examines this link by assessing the association between shared latrines compared with private latrines and risk of trachoma. In 2007, as part of a larger case-control study, we conducted a sub-study on latrine sharing in 594 households (92 cases, 502 controls) in seven rural Tanzanian communities. Case households were defined by having a child with clinical signs of trachoma. Latrine use was associated with a decreased risk of trachoma and there was no difference in risk between households using shared compared with private latrines (adjusted odds ratio = 0.95 [95% confidence interval = 0.55–1.67]). This study emphasizes the need to promote latrine use, which can be facilitated through latrine sharing in resource scarce areas, for prevention of trachoma.Understanding the relationship between sanitation practices and related diseases is important for developing effective strategies that address both access to sanitation and health outcomes.¹ Trachoma, the world''s leading cause of preventable blindness,² is particularly suited to sanitation studies. The disease is transmitted both directly and through mechanical transport by eye-seeking flies that breed in feces, preferring those of human origin.^3,4 Latrines allow for the safe removal of human feces from the environment, thereby eliminating fly breeding material and potentially blocking mechanical transmission.⁵Latrine use is associated with a decreased risk of trachoma in various sub-Saharan African countries.^6,7 However, the practice of latrine sharing and the effect on disease remains largely undocumented. Assessing latrine sharing and trachoma in sub-Saharan Africa is important given that an estimated 18% of individuals in the region use a shared latrine.⁸ The widespread use of shared latrines combined with a high prevalence of trachoma in the region⁹ provided the motivation to conduct this study. The objective is to compare the effectiveness of shared latrines to private latrines in preventing risk of trachoma in rural Tanzania. We examined households that share latrines as a single entity and grouped them into categories based on the number of households sharing latrines. We hypothesize that latrine sharing, especially when it involves many households, could lead to inadequate maintenance and overuse, thereby diminishing the association of latrines with decreased risk of trachoma.