Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: A cluster-randomized controlled trial in rural Bangladesh

• Published in: PLoS neglected tropical diseases 2019-05, Vol.13 (5), p.e0007323
• Main Authors: Ercumen, Ayse, Benjamin-Chung, Jade, Arnold, Benjamin F, Lin, Audrie, Hubbard, Alan E, Stewart, Christine, Rahman, Zahidur, Parvez, Sarker Masud, Unicomb, Leanne, Rahman, Mahbubur, Haque, Rashidul, Colford, Jr, John M, Luby, Stephen P
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Bangladesh - epidemiology; Biology and Life Sciences; Care and treatment; Child; Child, Preschool; Children; Clinical trials; Combined water; Control; Diet; Dietary supplements; Disease transmission; Drug resistance; Drugs; Ecology and Environmental Sciences; Feces; Feces - parasitology; Female; Fresh Water - parasitology; Hand Disinfection - methods; Handwashing; Health education; Helminthiasis; Helminthiasis - epidemiology; Helminthiasis - prevention & control; Helminthiasis - transmission; Helminths - classification; Helminths - genetics; Helminths - isolation & purification; Humans; Hygiene; Infection; Infection control; Infections; Infectious diseases; Intervention; Male; Medicine and Health Sciences; Nutrition; Nutrition Assessment; Parasites; Pregnancy; Pregnant Women; Public health; Public relations; Randomization; Retirement benefits; Risk factors; Sanitation; Sanitation - methods; Soil; Soil - parasitology; Survival; Systematic review; Technicians; Transmission; Tropical diseases; Water; Water treatment; Women
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0007323

Soil transmitted helminths (STH) infect >1.5 billion people. Mass drug administration (MDA) effectively reduces infection; however, there is evidence for rapid reinfection and risk of potential drug resistance. We conducted a randomized controlled trial in Bangladesh (WASH Benefits, NCT01590095) to assess whether water, sanitation, hygiene and nutrition interventions, alone and combined, reduce STH in a setting with ongoing MDA. In 2012-2013, we randomized 720 clusters of 5551 pregnant women into water treatment, sanitation, handwashing, combined water+sanitation+handwashing (WSH), nutrition, nutrition+WSH (N+WSH) or control arms. In 2015-2016, we enrolled 7795 children, aged 2-12 years, of 4102 available women for STH follow-up and collected stool from 7187. We enumerated STH infections with Kato-Katz. We estimated intention-to-treat intervention effects on infection prevalence and intensity. Participants and field staff were not blinded; laboratory technicians and data analysts were blinded. Prevalence among controls was 36.8% for A. lumbricoides, 9.2% for hookworm and 7.5% for T. trichiura. Most infections were low-intensity. Compared to controls, the water intervention reduced hookworm by 31% (prevalence ratio [PR] = 0.69 (0.50,0.95), prevalence difference [PD] = -2.83 (-5.16,-0.50)) but did not affect other STH. Sanitation improvements reduced T. trichiura by 29% (PR = 0.71 (0.52,0.98), PD = -2.17 (-4.03,-0.38)), had a similar borderline effect on hookworm and no effect on A. lumbricoides. Handwashing and nutrition interventions did not reduce any STH. WSH and N+WSH reduced hookworm prevalence by 29-33% (WSH: PR = 0.71 (0.52,0.99), PD = -2.63 (-4.95,-0.31); N+WSH: PR = 0.67 (0.50,0.91), PD = -3.00 (-5.14,-0.85)) and marginally reduced A. lumbricoides. Effects on infection intensity were similar. In a low-intensity infection setting with MDA, we found modest but sustained hookworm reduction from water treatment and combined WSH interventions. Impacts were more pronounced on STH species with short vs. long-term environmental survival. Our findings suggest possible waterborne transmission for hookworm. Water treatment and sanitation improvements can augment MDA to interrupt STH transmission. NCT01590095.