Eau et développement

Infectious disease transmission is frequently mediated by the environment, where people's movements through and interactions with the environment dictate risks of infection and/or illness. Capturing these interactions, and quantifying their importance, offers important insights into effective interventions. In this study, we capture high time-resolution activity data for twenty-five Vietnamese farmers during collection and land application of human excreta for agriculture. Although human excreta use improves productivity, the use increases risks of enteric infections for both farmers and end users. In our study, the activity data are integrated with environmental microbial sampling data into a stochastic-mechanistic simulation of E. coli contamination on hands and E. coli ingested. Results from the study include frequent and variable contact rates for farmers' hands (from 34 to 1344 objects contacted per hour per hand), including highly variable hand-to-mouth contact rates (from 0 to 9 contacts per hour per hand). The frequency of hand-to-mouth contacts was substantially lower than the widely-used frequency previously reported for U.S. Office Workers. Environmental microbial contamination data highlighted ubiquitous E. coli contamination in the environment, including excreta, hands, toilet pit, handheld tools, soils, surfaces, and water. Results from the simulation suggest dynamic changes in E. coli contamination on hands, and wide variation in hand contamination and E. coli ingested amongst the farmers studied. Sensitivity analysis suggests that E. coli contamination on hands and ingested doses are most influenced by contamination of handheld tools, excreta, and the toilet pit as well as by frequency of hand-to-mouth contacts. The study findings are especially relevant given the context: no farmers reported adequate storage time of human excreta, and personal protective mask availability did not prevent hand-to-mouth contacts. Integrating high time-resolution activity data into exposure assessments highlights variation in exposures amongst farmers, and offers greater insight into effective interventions and their potential impacts.

Escherichia coli pathotypes (i.e., enteropathogenic and enterotoxigenic) have been identified among the pathogens most responsible for moderate-to-severe diarrhea in low- and middle-income countries (LMICs). Pathogenic E. coli are transmitted from infected human or animal feces to new susceptible hosts via environmental reservoirs such as hands, water, and soil. Commensal E. coli, which includes nonpathogenic E. coli strains, are widely used as fecal bacteria indicator, with their presence associated with increased likelihood of enteric pathogens and/or diarrheal disease. In this study, we investigated E. coli contamination in environmental reservoirs within households (N = 142) in high-population density communities of Harare, Zimbabwe. We further assessed the interconnectedness of the environmental compartments by investigating associations between, and household-level risk factors for, E. coli contamination. From the data we collected, the source and risk factors for E. coli contamination are not readily apparent. One notable exception is the presence of running tap water on the household plot, which is associated with significantly less E. coli contamination of drinking water, handwashing water, and hands after handwashing. In addition, E. coli levels on hands after washing are significantly associated with handwashing water contamination, hand contamination before washing, and diarrhea incidence. Finally, we observed that animal ownership increases E. coli contamination in soil, and E. coli in soil are correlated with contamination on hands before washing. This study highlights the complexity of E. coli contamination in household environment within LMICs. More, larger, studies are needed to better identify sources and exposure pathways of E. coli—and enteric pathogens generally—to identify effective interventions.

Background: Community-led total sanitation (CLTS) is a widely used, community-based approach to tackle open defecation and its health-related problems. Although CLTS has been shown to be successful in previous studies, little is known about how CLTS works. We used a cross-sectional case study to identify personal, physical, and social context factors and psychosocial determinants from the Risks, Attitudes, Norms, Abilities, and Self-Regulation (RANAS) model of behavior change, which are crucial for latrine ownership and analyze how participation in CLTS is associated with those determinants.

Methods: Structured interviews were conducted with 640 households in 26 communities, where CLTS had been completed before and compared to 6 control communities, all located in northern Mozambique in 2015. To identify crucial factors for latrine ownership, logistic regression analysis were conducted and mediation analysis were used to analyse the relationship between CLTS participation and latrine ownership mediated by factors identified by the logistic regression analyses.

Results: Mediation analysis reveal that the relationship of CLTS participation with probability of owning a latrine is mediated by social context factors and psychosocial determinants. Data analysis reveal that the probability of building a latrine depends on existing social context factors within the village, the behavior of others in the community, the (dis)approval of others of latrine ownership, personal self-confidence in latrine building, and a precise communication of the benefits of latrine ownership during a CLTS triggering event.

Conclusions: By including activities to focus on the mentioned factors, CLTS could be improved. Exemplary adaptations are discussed.

Small scale wastewater treatment systems are a cost-effective and pragmatic alternative to large centralised systems in many contexts. However, despite the huge potential, very few low- and middle-income countries managed to scale-up such systems. This paper explores the barriers in the case of Egypt and provides recommendations to utilities and governments on how to create an enabling environment to do so. The main barriers are institutional. Utilities need to put into place drivers of change: think at scale, reach economies of scale both in terms of management and implementation, adapt the effluent standards and engage the private sector and civil society.