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Passive water chlorination reduces childhood diarrhea in Bangladesh
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Passively chlorinating water sources using solid tablet chlorine dosers significantly reduced the rate of childhood diarrhea in two communities in Dhaka, Bangladesh, according to results from a double-blind, cluster-randomized controlled trial published in The Lancet Global Health.
In the study, researchers used a device called Aquatabs Flo (Medentech) that automatically chlorinates water as it flows into a storage tank, without the need for electricity, cleaning it for collection.
“The chlorine dosers were installed at the point of collection and automatically provided safe water without requiring users to change the way they collect water,” Amy J. Pickering, PhD, MS, an assistant professor of civil and environmental engineering at Tufts University, told Infectious Diseases in Children. “Previous interventions have focused on household-level water treatment products that require daily effort from the user.”
According to Pickering and colleagues, even though water may be safe to drink at its source, it is often contaminated by the time it is collected.
They conducted the trial at 100 shared water sources in two low-income urban communities in the Bangladeshi capital. The researchers chlorinated half of the water sources using the tablet doser, and half received an identical-looking vitamin C doser. Following the administration of the intervention or placebo, children aged younger than age 5 years in households using the water sources were assessed for diarrhea every 2 to 3 months over the course of 14 months.
The researchers defined diarrhea according to WHO criteria, which includes three or more loose or watery stools occurring within 24 hours.
More than 900 households enrolled in the study, with 517 children randomly assigned to chlorination and 519 children randomly assigned to placebo. Children receiving the intervention had fewer instances of diarrhea compared with those receiving placebo (7.5% vs. 10%; prevalence ratio = 0.77; 95% CI, 0.65-0.91). The researchers wrote that detectable free chlorine residual was found 83% of the time in treated water sources (average = 0.37 ppm) compared with 0% in untreated sources.
According to Pickering and colleagues, they chose the chlorine dose based on previous research the group conducted in which they found that the taste of the water remained acceptable up to 0.5 ppm in these communities.
“Chlorine is one of the lowest cost water treatment options, and there are now a variety of in-line chlorine dosing products available in low-income markets,” Pickering said. “This study provides strong evidence that point-of-collection chlorination is an effective strategy for preventing child diarrhea in low-income urban settings. Future trials measuring the health benefits of installing the technology in institutional settings and in rural communities would be valuable.” – by Katherine Bortz
Disclosures: Pickering and Luby report receiving salary support from the World Bank during the study. Please see the study for all other authors’ relevant financial disclosures.
Perspective
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Andi L. Shane, MD, MPH, MSc
The quest for an effective and acceptable solution to reduce childhood diarrhea in resource-challenged settings has been met with numerous challenges. Point-of-use household water treatment approaches have not been as effective or sustainable as hoped.
A passive engineering approach using an automated in-line chlorination device installed at shared water points, such as the one assessed by Pickering and colleagues, is innovative because it eliminates the need for active engagement with the water treatment process. In addition to caregiver-reported, WHO-defined diarrhea in children aged younger than 5 years, it would be interesting to assess the impact of this passive chlorination device on illness episodes, both reported and medically attended, among other consumers of inline-treated water because the impact is likely to extend beyond the outcome assessed in this trial. This strategy holds promise to reduce the burden of diarrheal disease in similar resource-challenged settings where access to safe water is not yet available.
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