Effects of an urban sanitation intervention on childhood enteric infection and diarrhea in Maputo, Mozambique: A controlled before-and-after trial

Abstract

We conducted a controlled before-and-after trial to evaluate the impact of an onsite urban sanitation intervention on the prevalence of enteric infection, soil transmitted helminth re-infection, and diarrhea among children in Maputo, Mozambique. A non-governmental organization replaced existing poor-quality latrines with pour-flush toilets with septic tanks serving household clusters. We enrolled children aged 1-48 months at baseline and measured outcomes before and 12 and 24 months after the intervention, with concurrent measurement among children in a comparable control arm. Despite nearly exclusive use, we found no evidence that intervention affected the prevalence of any measured outcome after 12 or 24 months of exposure. Among children born into study sites after intervention, we observed a reduced prevalence of Trichuris and Shigella infection relative to the same age group at baseline (<2 years old). Protection from birth may be important to reduce exposure to and infection with enteric pathogens in this setting.

Trial registration: ClinicalTrials.gov NCT02362932.

Keywords: diarrhea; enteric infection; environmental health; epidemiology; global health; human; medicine; neglected tropical diseases; sanitation; soil-transmitted helminths.

Figure 1.. Trial profile.

*Eligible for enrollment at baseline and/or 12 months but traveling at time of visit. †Children removed from 24-month analysis because their compound received an intervention after completion of the baseline phase. Source files available in Figure 1—source data 1 and Figure 1—source code 1.

Appendix 1—figure 1.. Proportion of each type of sample collected during the baseline, 12-month, and 24-month phases.

Results stratified by study arm. Rectal swabs were not introduced until the 12-month phase of the study.

Appendix 1—figure 2.. Enrollment and stool sample collection profile.

Graphs depict 4-week rolling average of the number of intervention and control children enrolled/visited (solid lines) and the number of stool samples collected (including whole stool, diaper samples, and rectal swabs) during the baseline, 12-month, and 24-month phases. The overall success of stool sample collection was 78% at baseline, 86% at 12 month, and 90% at 24 month. The increase in success rate was due to the introduction of rectal swab collection during the 12-month phase.

Appendix 1—figure 3.. Distribution of age (years) of enrolled children at each phase.

Results are presented as kernel density plots and stratified by study arm (intervention=blue, control=green) and phase: (a) Baseline phase, (b) 12-month follow-up, (c) 24-month follow-up, and (d) All phases combined.

Appendix 1—figure 4.. Prevalence of pathogens by age at baseline, 12-month, and 24-month phases.

Results are smoothed averages stratified by study arm with 95% confidence intervals represented by shaded areas.

Appendix 1—figure 5.. Schematic of communal sanitation block design from the NGO (Water and Sanitation for the Urban Poor).

Pictured: two latrine stalls, two pour-flush toilets, septic tank, elevated water storage tank, laundry basin, door. Not pictured: soakaway pit. Source: Water and Sanitation for the Urban Poor.

Appendix 1—figure 6.. Construction of a soakaway pit for discharge of liquid effluent from intervention latrines.

Appendix 1—figure 7.. Photo of communal sanitation block as constructed.

Appendix 1—figure 8.. Photo of shared latrine as constructed.

Appendix 1—figure 9.. Map illustrating locations of intervention (n=208) and control sites (n=287) compounds.