A Faecal Contamination Index for interpreting heterogeneous diarrhoea impacts of water, sanitation and hygiene interventions and overall, regional and country estimates of community sanitation coverage with a focus on low- and middle-income countries

Abstract

ObjectivesThe impact on diarrhoea of sanitation interventions has been heterogeneous. We hypothesize that this is due to the level of prevailing faecal environmental contamination and propose a Faecal Contamination Index (FAECI) of selected WASH indicators (objective 1). Additionally, we provide estimates of the proportion of the population living in communities above certain sanitation coverage levels (objective 2).MethodsObjective 1: Faecal contamination post-intervention was estimated from WASH intervention reports. WASH indicators composing the FAECI included eight water, sanitation and hygiene practice indicators, which were selected for their relevance for health and data availability at study- and country-level. The association between the estimated level of faecal environmental contamination and diarrhoea was examined using meta-regression. Objective 2: A literature search was conducted to identify health-relevant community sanitation coverage thresholds. To estimate total community coverage with basic sanitation in low- and middle-income countries, at relevant thresholds, household surveys with data available at primary sampling unit (PSU)-level were analysed according to the identified thresholds, at country-, regional- and overall level.ResultsObjective 1: We found a non-linear association between estimated environmental faecal contamination and sanitation interventions’ impact on diarrhoeal disease. Diarrhoea reductions were highest at lower faecal contamination levels, and no diarrhoea reduction was found when contamination increased above a certain level. Objective 2: Around 45% of the population lives in communities with more than 75% of coverage with basic sanitation and 24% of the population lives in communities above 95% coverage, respectively.ConclusionsHigh prevailing faecal contamination might explain interventions' poor effectiveness in reducing diarrhoea. The here proposed Faecal Contamination Index is a first attempt to estimate the level of faecal contamination in communities. Much of the world's population currently lives in faecally contaminated environments as indicated by low community sanitation coverage.

Costs, Climate and Contamination: Three Drivers for Citywide Sanitation Investment Decisions

“…Low-income households are at greater risk from exposure, as they are more likely to be in areas affected by sewage and septage overflow during floods (Hawkins et al, 2013).The identification of locally important key fecal transmission pathways, and an understanding of a person's full exposure to fecal pathogens, can provide valuable information for the prioritization of interventions (Robb et al, 2017;WHO, 2018;Wang et al, 2018). Various studies have found that exposure and health risks are associated not only with an individual's sanitation but also the sanitation of their communities (Hunter and Prüss-Ustün, 2016;Wolf et al, 2019). For example, in Timor-Leste, although only 7% of the urban population uses toilets that flush to an open drain, 55% live in communities where at least one household uses a toilet that flushes to an open drain, potentially exposing many households in the neighborhood to pathogens (UNICEF and WHO, 2019).…”

When, how, and how long do adults in Germany self-reportedly wash their hands? Compliance indices based on handwashing frequency, technique, and duration from a cross-sectional representative survey

“…Values of this variable >0 were trichotomized into approximately equal groups, yielding groups with 1–3, 4–6, or 7–9 indications with compliant handwashing frequency. Following a practice by Wolf et al (2019b) , these choices were made subjectively “… as a simplified approach and in order to get a good distribution of scores” ( Wolf et al, 2019b , p. 272).…”

SARS-CoV-2 in wastewater: Challenges for developing countries

“…The Ebola outbreak in 2014–2016 undermined malaria control efforts and led to a massive increase in malaria-related illness and death in the three West African countries ( WHO, 2020c ). Safe drinking-water, sanitation and hygiene interventions may be helpful to reduce risk of faecal contamination of the living environment ( Wolf et al, 2019 ). Frequent hand-washing with soap should be adopted to prevent the spread of infection.…”