Background
Unsafe drinking water and household air pollution are leading risk factors for diarrhoea and
pneumonia, two major causes of death for young children. Rural areas are vulnerable due to
unsafe water supplies and biomass burned indoors for cooking. Household water filters and
portable fuel-efficient cookstoves could reduce these risks, but there is limited evidence of longterm
uptake and impact.
National Water Quality Study
To determine the extent of faecal contamination of household stored drinking water and
associated risk factors in Rwanda, we conducted a nationally representative cross-sectional
study. Only 24.9% (n=217) of household supplies met WHO Guidelines of no detectable faecal
contamination (thermotolerant coliforms (TTC)). Risk factors for intermediate and/or high risk
contamination (11-100 and 101+ TTC/100mL) included low population density, increased open
waste disposal within a sector, lower elevation, water sources other than piped to household or
rainwater/bottled, and occurrence of an extreme rain event the previous day. Thus, communitylevel
factors are associated with stored household water quality; observed contamination poses
a health risk in Rwanda.
Matched Cohort Study
We next conducted a matched-cohort study in 18 villages to assess uptake, exposure, and health
impacts of a water filter and improved biomass cookstove intervention programme 13-24
months after receipt. Coverage and use of the filter and cookstove was high, but non-exclusive.
The odds of detecting TTC were 78% lower in the intervention arm (OR 0.22, p<0.001), with 50%
lower odds of reported diarrhoea among intervention children <5 (OR=0.50, p=0.03). The
5
intervention was associated with 43.4% lower fine particulate matterin kitchens (p<0.001), but
geometric mean exposure remained above WHO targets for cooks (151 μg/m3
) and children (175
μg/m3
), and only marginally reduced among intervention cooks (22.2% lower, p=0.06). While the
filter showed promise for health benefits, alternative household and community-level
approaches for achieving clean, safe air are needed.