Effects of Water, Sanitation, Handwashing, and Nutritional Interventions on Child Enteric Protozoan Infections in Rural Bangladesh: A Cluster-Randomized Controlled Trial

Abstract

Background: We evaluated effects of individual and combined water, sanitation, handwashing (WSH), and nutritional interventions on protozoan infections in children.

Methods: We randomized geographical clusters of pregnant women in rural Bangladesh into chlorinated drinking water, hygienic sanitation, handwashing, nutrition, combined WSH, nutrition plus WSH (N+WSH), or control arms. Participants were not masked. After approximately 2.5 years of intervention, we measured Giardia, Cryptosporidium, and Entamoeba histolytica prevalence and infection intensity by multiplex real-time polymerase chain reaction of child stool. Analysis was intention-to-treat.

Results: Between May 2012 and July 2013, we randomized 5551 pregnant women. At follow-up, among 4102 available women, we enrolled 6694 children into the protozoan assessment. We analyzed stool from 5933 children (aged ~31 months) for protozoan infections. Compared with 35.5% prevalence among controls, Giardia infection prevalence was lower in the sanitation (26.5%; prevalence ratio [PR], 0.75 [95% confidence interval {CI}, .64-.88]), handwashing (28.2%; PR, 0.80 [95% CI, .66-.96]), WSH (29.7%; PR, 0.83 [95% CI, .72-.96]), and N+WSH (26.7%; PR, 0.75 [95% CI, .64-.88]) arms. Water and nutrition interventions had no effect. Low prevalence of E. histolytica and Cryptosporidium (<2%) resulted in imprecise effect estimates.

Conclusions: Individual handwashing and hygienic sanitation interventions significantly reduced childhood Giardia infections, and there were no effects of chlorinated drinking water and nutrition improvements in this context. Combined WSH interventions provided no additional benefit. To reduce Giardia infection, individual WSH interventions may be more feasible and cost-effective than combined interventions in similar rural, low-income settings.

Clinical trials registration: NCT01590095.

Figure 1.

Flowchart of study participants’ progress through the phases of the trial. Index child is a child born to an enrolled pregnant woman, including twins. Index household refers to a household where an index child in the birth cohort lived. Index household child is an older child living in the index household who is not the index child. Other household child is a child who does not live in the index household but lives in the shared compound. Abbreviations: HH, household; N+WSH, combined nutrition, water treatment, sanitation, and handwashing.

Figure 2.

Intervention effects on Giardia prevalence among children living in index households approximately 2.5 years after intervention initiation. Abbreviations: CI, confidence interval; H, handwashing; S, sanitation; W, water treatment; WSH, combined water treatment, sanitation, and handwashing.

Figure 3.

Intervention effects on Giardia infection intensity (cycle threshold [Ct] values) among children living in index households approximately 2.5 years after intervention initiation. Relative reduction of infection intensity is defined as CR – 1, where CR is the ratio of Ct values between arms. Nondetects were imputed as a Ct value of 40. Abbreviations: CI, confidence interval; Ct, cycle threshold; H, handwashing; S, sanitation; W, water treatment; WSH, combined water treatment, sanitation, and handwashing.