Characteristics of Latrines in Central Tanzania and Their Relation to Fly Catches

This journal paper by Irish et al. (2013) published in PLOS ONE, presents the findings of a pilot study investigating the association between latrine design, management, the chemical and physical characteristics of pit contents and fly presence in latrines. Until this study, little was known about why despite the widespread availability of latrines and fairly standard contents, not all latrines produce equal numbers of flies. The characteristics of the latrine superstructure, use of the latrine, and chemical characteristics of pit latrine contents were compared to the numbers of flies collected in an exit trap placed over the drop hole in the latrine in 50 latrines in and around Ifakara, Tanzania. The study found that the absence of a roof had a significant positive association with the total number of flies collected, and that temporary superstructures and increased total solids in pit latrines were both significantly associated with increased numbers of blowflies leaving the latrine. Other factors affecting fly catch included the volatile solids in pit latrine contents, and the location of the latrine. The paper concludes that the effect of latrine superstructure (roof, walls) on fly production may indicate that improvements in latrine construction could result in decreases in fly populations in areas where they transmit diarrhoeal pathogens.