Household finished flooring as a guard against enteric illness in children
Authors: Nepal C Dey, Mahmood Parvez
Journal: The Lancet Global Health (2021)

Soil-transmitted helminth and Giardia duodenalis infections are among the most common worldwide, and are major public health problems, especially for children from the poorest and most deprived communities around the world.1WHOSoil-transmitted helminth infections: fact sheet.https://www.who.int/news-room/fact-sheets/detail/soil-transmitted-helminth-infectionsDate: 2020Date accessed: December 27, 2020Google Scholar Infection with enteric pathogens in children often results in malnutrition, absenteeism, and poor school performance, delayed physical growth, and impaired cognitive function and mental growth.2Botero D Restrepo M Parasitosis humanas. Corporación para investigaciones Biológicas CIB, 2012Google Scholar, 3De Silva NR Brooker S Hotez PJ Montresor A Engels D Savioli L Soil-transmitted helminth infections: updating the global picture.Trends Parasitol. 2003; 19: 547-551Summary Full Text Full Text PDF PubMed Scopus (804) Google Scholar The primary soil-transmitted helminth control strategy is administering mass preventive chemotherapy in populations at risk. Improved water, sanitation, and hygiene (WASH) interventions—another common control strategy—show different degrees of reduction in transmission of soil-transmitted helminth and G duodenalis infections.4Strunz EC Addiss DG Stocks ME Ogden S Utzinger J Freeman MC Water, sanitation, hygiene, and soil-transmitted helminth infection: a systematic review and meta-analysis.PLoS Med. 2014; 11e1001620Crossref PubMed Scopus (430) Google Scholar, 5Ercumen A Benjamin-Chung J Arnold BF et al.Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: a cluster-randomized controlled trial in rural Bangladesh.PLoS Negl Trop Dis. 2019; 13e0007323Crossref PubMed Scopus (25) Google Scholar Installation of household finished flooring (eg, cement, tile, wood) might be a simple, but effective, intervention against soil-transmitted helminth and G duodenalis transmission among children, by reducing the probability of faecal contact of hands, toys, food, and water. However, evidence supporting the association between finished flooring and lower risk of soil-transmitted helminth and G duodenalis infections are mostly based on cross-sectional studies.6Krause RJ Koski KG Pons E Sandoval N Sinisterra O Scott ME Ascaris and hookworm transmission in preschool children from rural Panama: role of yard environment, soil eggs/larvae and hygiene and play behaviours.Parasitology. 2015; 142: 1543-1554Crossref PubMed Scopus (10) Google Scholar, 7Basualdo JA Córdoba MA de Luca MM et al.Intestinal parasitoses and environmental factors in a rural population of Argentina, 2002–2003.Rev Inst Med Trop Sao Paulo. 2007; 49: 251-255Crossref PubMed Scopus (53) Google Scholar The study by Jade Benjamin-Chung and colleagues in The Lancet Global Health8Benjamin-Chung J Crider Y S Mertens A et al.Household finished flooring and soil-transmitted helminth and Giardia infections among children in rural Bangladesh and Kenya: a prospective cohort study.Lancet Glob Health. 2021; 9: e301-e308Summary Full Text Full Text PDF PubMed Scopus (7) Google Scholar investigated this topic in a cohort of children born into households with different flooring conditions in Bangladesh and Kenya. Analysis of prospectively collected data from children in cohorts in two countries thus generated evidence on this association, and improves on the previous studies on this topic. Furthermore, Benjamin-Chung and colleagues’ study provides a more accurate detection of infections than earlier studies, because it used rigorous molecular diagnostic methods to detect infections that might be missed by the more common copromicroscopic methods, and hence offers a more reliable estimate of association between finished flooring and risk of soil-transmitted helminth and G duodenalis infections. The findings presented in Benjamin-Chung and colleagues’ study strengthens the evidence that finished flooring might act as a protective factor against soil-transmitted helminth and G duodenalis transmission. Because the reported magnitude of protective association between finished flooring and enteric illness among children is as good as WASH and preventive chemotherapy interventions,5Ercumen A Benjamin-Chung J Arnold BF et al.Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: a cluster-randomized controlled trial in rural Bangladesh.PLoS Negl Trop Dis. 2019; 13e0007323Crossref PubMed Scopus (25) Google Scholar it can be a more advantageous option than other methods, when considering the minimum required sustained behavioural change and easier maintenance. The study encompassed cohorts in two countries, with different geographical, ecological, social, and cultural contexts and different disease transmission dynamics, but with similar results, making the findings more generalisable for rural low-income settings. Benjamin-Chung and colleagues’ study thus provides a key message to the actors and policy makers working on enteric pathogen infection control: finished flooring, as an environmental intervention, should be considered as a pragmatic option to target enteric parasite transmission pathways in low-resource settings. However, because the study was observational in nature, it was not possible for the authors to explore various confounders that might have potentially biased their findings. Thus, the causal relationship between finished flooring and reduction in soil-transmitted helminth and G duodenalis infections should be explored in future studies. It is probable that different finishes (eg, wooden, cement, and tiled flooring) might offer different levels of protection against soil-transmitted helminth and enteric protozoan infection. Future studies should adopt randomised trials of households with various types of floors as different study groups to measure the comparative effect of type of floor material on enteric parasite infections. Benjamin-Chung and colleagues’ study was limited to rural settings of Bangladesh and Kenya, and therefore could not explore the rural–urban difference in association of finished flooring and reduced risk of enteric pathogen infection. This perspective is immensely important and needs exploration, because a significant proportion (29·4%) of the global urban population lives in informal settlements,9The World BankThe World Bank data: Population living in slums.https://data.worldbank.org/indicator/EN.POP.SLUM.UR.ZSDate: 2018Date accessed: December 29, 2020Google Scholar where the living conditions and environments are completely different to rural settings. It is essential to understand to what extent an intervention such as finished flooring acts as a protective factor against infection in settings where hygiene conditions differ to those in typical rural and urban settings.10Rana MDS Status of water use sanitation and hygienic condition of urban slums: a study on Rupsha Ferighat slum, Khulna.Desalination. 2009; 246: 322-328Crossref Scopus (9) Google Scholar Nevertheless, the Benjamin-Chung and colleagues’ study has added great value to the existing research on this topic, and has generated much that should be considered by both researchers and policy makers. As outlined by the authors of the Article, household finished flooring has the potential to complement preventive chemotherapy, by reducing the reinfection; which should be explored in future research. Future experimental studies, which will build on the findings of this Article, will help to formulate appropriate policy, design focused interventions, and will greatly benefit the efforts to control enteric pathogen transmission and subsequent enteric illness among children in resource-poor settings.We declare no competing interests. Soil-transmitted helminth and Giardia duodenalis infections are among the most common worldwide, and are major public health problems, especially for children from the poorest and most deprived communities around the world.1WHOSoil-transmitted helminth infections: fact sheet.https://www.who.int/news-room/fact-sheets/detail/soil-transmitted-helminth-infectionsDate: 2020Date accessed: December 27, 2020Google Scholar Infection with enteric pathogens in children often results in malnutrition, absenteeism, and poor school performance, delayed physical growth, and impaired cognitive function and mental growth.2Botero D Restrepo M Parasitosis humanas. Corporación para investigaciones Biológicas CIB, 2012Google Scholar, 3De Silva NR Brooker S Hotez PJ Montresor A Engels D Savioli L Soil-transmitted helminth infections: updating the global picture.Trends Parasitol. 2003; 19: 547-551Summary Full Text Full Text PDF PubMed Scopus (804) Google Scholar The primary soil-transmitted helminth control strategy is administering mass preventive chemotherapy in populations at risk. Improved water, sanitation, and hygiene (WASH) interventions—another common control strategy—show different degrees of reduction in transmission of soil-transmitted helminth and G duodenalis infections.4Strunz EC Addiss DG Stocks ME Ogden S Utzinger J Freeman MC Water, sanitation, hygiene, and soil-transmitted helminth infection: a systematic review and meta-analysis.PLoS Med. 2014; 11e1001620Crossref PubMed Scopus (430) Google Scholar, 5Ercumen A Benjamin-Chung J Arnold BF et al.Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: a cluster-randomized controlled trial in rural Bangladesh.PLoS Negl Trop Dis. 2019; 13e0007323Crossref PubMed Scopus (25) Google Scholar Installation of household finished flooring (eg, cement, tile, wood) might be a simple, but effective, intervention against soil-transmitted helminth and G duodenalis transmission among children, by reducing the probability of faecal contact of hands, toys, food, and water. However, evidence supporting the association between finished flooring and lower risk of soil-transmitted helminth and G duodenalis infections are mostly based on cross-sectional studies.6Krause RJ Koski KG Pons E Sandoval N Sinisterra O Scott ME Ascaris and hookworm transmission in preschool children from rural Panama: role of yard environment, soil eggs/larvae and hygiene and play behaviours.Parasitology. 2015; 142: 1543-1554Crossref PubMed Scopus (10) Google Scholar, 7Basualdo JA Córdoba MA de Luca MM et al.Intestinal parasitoses and environmental factors in a rural population of Argentina, 2002–2003.Rev Inst Med Trop Sao Paulo. 2007; 49: 251-255Crossref PubMed Scopus (53) Google Scholar The study by Jade Benjamin-Chung and colleagues in The Lancet Global Health8Benjamin-Chung J Crider Y S Mertens A et al.Household finished flooring and soil-transmitted helminth and Giardia infections among children in rural Bangladesh and Kenya: a prospective cohort study.Lancet Glob Health. 2021; 9: e301-e308Summary Full Text Full Text PDF PubMed Scopus (7) Google Scholar investigated this topic in a cohort of children born into households with different flooring conditions in Bangladesh and Kenya. Analysis of prospectively collected data from children in cohorts in two countries thus generated evidence on this association, and improves on the previous studies on this topic. Furthermore, Benjamin-Chung and colleagues’ study provides a more accurate detection of infections than earlier studies, because it used rigorous molecular diagnostic methods to detect infections that might be missed by the more common copromicroscopic methods, and hence offers a more reliable estimate of association between finished flooring and risk of soil-transmitted helminth and G duodenalis infections. The findings presented in Benjamin-Chung and colleagues’ study strengthens the evidence that finished flooring might act as a protective factor against soil-transmitted helminth and G duodenalis transmission. Because the reported magnitude of protective association between finished flooring and enteric illness among children is as good as WASH and preventive chemotherapy interventions,5Ercumen A Benjamin-Chung J Arnold BF et al.Effects of water, sanitation, handwashing and nutritional interventions on soil-transmitted helminth infections in young children: a cluster-randomized controlled trial in rural Bangladesh.PLoS Negl Trop Dis. 2019; 13e0007323Crossref PubMed Scopus (25) Google Scholar it can be a more advantageous option than other methods, when considering the minimum required sustained behavioural change and easier maintenance. The study encompassed cohorts in two countries, with different geographical, ecological, social, and cultural contexts and different disease transmission dynamics, but with similar results, making the findings more generalisable for rural low-income settings. Benjamin-Chung and colleagues’ study thus provides a key message to the actors and policy makers working on enteric pathogen infection control: finished flooring, as an environmental intervention, should be considered as a pragmatic option to target enteric parasite transmission pathways in low-resource settings. However, because the study was observational in nature, it was not possible for the authors to explore various confounders that might have potentially biased their findings. Thus, the causal relationship between finished flooring and reduction in soil-transmitted helminth and G duodenalis infections should be explored in future studies. It is probable that different finishes (eg, wooden, cement, and tiled flooring) might offer different levels of protection against soil-transmitted helminth and enteric protozoan infection. Future studies should adopt randomised trials of households with various types of floors as different study groups to measure the comparative effect of type of floor material on enteric parasite infections. Benjamin-Chung and colleagues’ study was limited to rural settings of Bangladesh and Kenya, and therefore could not explore the rural–urban difference in association of finished flooring and reduced risk of enteric pathogen infection. This perspective is immensely important and needs exploration, because a significant proportion (29·4%) of the global urban population lives in informal settlements,9The World BankThe World Bank data: Population living in slums.https://data.worldbank.org/indicator/EN.POP.SLUM.UR.ZSDate: 2018Date accessed: December 29, 2020Google Scholar where the living conditions and environments are completely different to rural settings. It is essential to understand to what extent an intervention such as finished flooring acts as a protective factor against infection in settings where hygiene conditions differ to those in typical rural and urban settings.10Rana MDS Status of water use sanitation and hygienic condition of urban slums: a study on Rupsha Ferighat slum, Khulna.Desalination. 2009; 246: 322-328Crossref Scopus (9) Google Scholar Nevertheless, the Benjamin-Chung and colleagues’ study has added great value to the existing research on this topic, and has generated much that should be considered by both researchers and policy makers. As outlined by the authors of the Article, household finished flooring has the potential to complement preventive chemotherapy, by reducing the reinfection; which should be explored in future research. Future experimental studies, which will build on the findings of this Article, will help to formulate appropriate policy, design focused interventions, and will greatly benefit the efforts to control enteric pathogen transmission and subsequent enteric illness among children in resource-poor settings. We declare no competing interests. Household finished flooring and soil-transmitted helminth and Giardia infections among children in rural Bangladesh and Kenya: a prospective cohort studyIn low-resource settings, living in households with finished floors over a 2-year period was associated with lower prevalence of G duodenalis and some soil-transmitted helminths in children. Full-Text PDF Open Access