Protocol for the PATHOME study: a cohort study on urban societal development and the ecology of enteric disease transmission among infants, domestic animals and the environment

INTRODUCTION

Global morbidity from enteric infections and diarrhoea remains high in children in low-income and middle-income countries, despite significant investment over recent decades in health systems and water and sanitation infrastructure. Other types of societal development may be required to reduce disease burden. Ecological research on the influence of household and neighbourhood societal development on pathogen transmission dynamics between humans, animals and the environment could identify more effective strategies for preventing enteric infections.

METHODS AND ANALYSIS

The 'enteric pathome'-that is, the communities of viral, bacterial and parasitic pathogens transmitted from human and animal faeces through the environment is taxonomically complex in high burden settings. This integrated cohort-exposure assessment study leverages natural socioeconomic spectrums of development to study how pathome complexity is influenced by household and neighbourhood infrastructure and hygiene conditions. We are enrolling under 12-month-old children in low-income and middle-income neighbourhoods of two Kenyan cities (Nairobi and Kisumu) into a 'short-cohort' study involving repeat testing of child faeces for enteric pathogens. A mid-study exposure assessment documenting infrastructural, behavioural, spatial, climate, environmental and zoonotic factors characterises pathogen exposure pathways in household and neighbourhood settings. These data will be used to inform and validate statistical and agent-based models (ABM) that identify individual or combined intervention strategies for reducing multipathogen transmission between humans, animals and environment in urban Kenya.

ETHICS AND DISSEMINATION

The protocols for human subjects' research were approved by Institutional Review Boards at the University of Iowa (ID-202004606) and AMREF Health Africa (ID-ESRC P887/2020), and a national permit was obtained from the Kenya National Commission for Science Technology and Innovation (ID# P/21/8441). The study was registered on Clinicaltrials.gov (Identifier: NCT05322655) and is in pre-results stage. Protocols for research on animals were approved by the University of Iowa Animal Care and Use Committee (ID 0042302).

A systematic review and meta-analysis of pathogen reduction in onsite sanitation systems

The safe management of fecal sludge from the 3.4 billion people worldwide that use onsite sanitation systems can greatly reduce the global infectious disease burden. However, there is limited knowledge about the role of design, operational, and environmental factors on pathogen survival in pit latrines, urine diverting desiccation toilets, and other types of onsite toilets. We conducted a systematic literature review and meta-analysis to characterize pathogen reduction rates in fecal sludge, feces, and human excreta with respect to pH, temperature, moisture content, and the use of additives for desiccation, alkalinization, or disinfection. A meta-analysis of 1,382 data points extracted from 243 experiments described in 26 articles revealed significant differences between the decay rates and T₉₉ values of pathogens and indicators from different microbial groups. The overall median T₉₉ values were 4.8 days, 29 days, >341 days, and 429 days for bacteria, viruses, protozoan (oo)cysts, and Ascaris eggs, respectively. As expected, higher pH values, higher temperatures, and the application of lime all significantly predicted greater pathogen reduction rates but the use of lime by itself was more effective for bacteria and viruses than for Ascaris eggs, unless urea was also added. In multiple lab-scale experiments, the application of urea with enough lime or ash to reach a pH of 10 - 12 and a sustained concentration of 2,000 - 6,000 mg/L of non-protonated NH_3-N reduced Ascaris eggs more rapidly than without urea. In general, the storage of fecal sludge for 6 months adequately controls hazards from viruses and bacteria, but much longer storage times or alkaline treatment with urea and low moisture or heat is needed to control hazards from protozoa and helminths. More research is needed to demonstrate the efficacy of lime, ash, and urea in the field. More studies of protozoan pathogens are also needed, as very few qualifying experiments were found for this group.

Modelling rotavirus concentrations in rivers: Assessing Uganda's present and future microbial water quality

Faecal pathogens can be introduced into surface water through open defecation, illegal disposal and inadequate treatment of faecal sludge and wastewater. Despite sanitation improvements, poor countries are progressing slowly towards the United Nation's Sustainable Development Goal 6 by 2030. Sanitation-associated pathogenic contamination of surface waters impacted by future population growth, urbanization and climate change receive limited attention. Therefore, a model simulating human rotavirus river inputs and concentrations was developed combining population density, sanitation coverage, rotavirus incidence, wastewater treatment and environmental survival data, and applied to Uganda. Complementary surface runoff and river discharge data were used to produce spatially explicit rotavirus outputs for the year 2015 and for two scenarios in 2050. Urban open defecation contributed 87%, sewers 9% and illegal faecal sludge disposal 3% to the annual 15.6 log₁₀ rotavirus river inputs in 2015. Monthly concentrations fell between -3.7 (Q5) and 2.6 (Q95) log₁₀ particles per litre, with 1.0 and 2.0 median and mean log₁₀ particles per litre, respectively. Spatially explicit outputs on 0.0833 × 0.0833° grids revealed hotspots as densely populated urban areas. Future population growth, urbanization and poor sanitation were stronger drivers of rotavirus concentrations in rivers than climate change. The model and scenario analysis can be applied to other locations.

Why pathogens matter for meeting the united nations' sustainable development goal 6 on safely managed water and sanitation

Water and wastewater utilities, water and sanitation hygiene (WASH) practitioners, and regulating bodies, particularly in developing nations, rely heavily on indicator microorganisms, as opposed to pathogens, for much of their regulatory decisions. This commentary illustrates the importance of considering pathogens and not relying only on indicator organisms when making decisions regarding water and sanitation, especially with respect to meeting the current targets of the Sustainable Development Goal (SDG) 6. We use quantitative microbial risk assessment (QMRA) to present three common scenarios that WASH and public health practitioners encounter to illustrate our point. These include 1) chlorination of surface water for drinking, 2) land application of latrine waste as a fertilizer, and 3) recreation/domestic use of surface waters impacted by wastewater discharge. We show that the calculated probabilities of risk of infection are statistically significantly higher when using treatment/survival information for pathogens versus using indicator species data. Thus, demonstrating that relying solely on indicators for sanitation decision making is inadequate if we truly want to achieve the SDG6 targets of safely managed water and sanitation services.

Where Shared Sanitation is the Only Immediate Option: A Research Agenda for Shared Sanitation in Densely Populated Low-Income Urban Settings

Shared sanitation is not currently accepted within the international normative definitions of "basic" or "safely managed" sanitation. We argue that pro-poor government strategies and investment plans must include high-quality shared sanitation as an intermediate step in some densely populated urban areas. User experience must be considered in establishing the definition of high quality. We call for additional research on effective interventions to reach these quality standards and for the development of rigorous measures applicable to global monitoring.

Translating pathogen knowledge to practice for sanitation decision-making

Sanitation planners make complex decisions in the delivery of sanitation services to achieve health outcomes. We present findings from a stakeholder engagement workshop held in Kampala, Uganda, to educate, interact with, and solicit feedback from participants on how the relevant scientific literature on pathogens can be made more accessible to practitioners to support decision-making. We targeted Water, Sanitation and Hygiene (WASH) practitioners involved in different levels of service delivery. Practitioners revealed that different sanitation planning tools are used to inform decision-making; however, most of these tools are not user-friendly or adapted to meet their needs. Most stakeholders (68%) expressed familiarity with pathogens, yet less than half (46%) understood that fecal coliforms were bacteria and used as indicators for fecal pollution. A number of stakeholders were unaware that fecal indicator bacteria do not behave and persist the same as helminths, protozoa, or viruses, making fecal indicator bacteria inadequate for assessing pathogen reductions for all pathogen groups. This suggests a need for awareness and capacity development around pathogens found in excreta. The findings underscore the importance to engage stakeholders in the development of support tools for sanitation planning and highlighted broader opportunities to bridge science with practice in the WASH sector.

Effectiveness of group discussions and commitment in improving cleaning behaviour of shared sanitation users in Kampala, Uganda slums

RATIONALE AND OBJECTIVE

Access to and use of hygienic shared sanitation facilities is fundamental in reducing the high risk of diseases such as diarrhoea and respiratory infections. We evaluated the effectiveness of group discussions and commitment in improving the cleaning behaviour of shared sanitation users in three urban slums in Kampala, Uganda. The study follows the risk, attitudes, norms, abilities and self-regulation (RANAS) model of behaviour change and some factors of the social dilemma theory.

METHODS

A pre-versus post-intervention survey was conducted in three slums of Kampala, Uganda, between December 2012 and September 2013. From the pre-intervention findings, users of dirty sanitation facilities were randomly assigned to discussions, discussions + commitment and control interventions. The interventions were implemented for 3 months with the aim of improving cleaning behaviour. This paper provides an analysis of 119 respondents who belonged to the intervention discussion-only (n = 38), discussions + commitment (n = 41) and the control (no intervention, n = 40) groups.

RESULTS

Compared to the control, discussions and discussions + commitment significantly improved shared toilet users' cleaning behaviour. The rate of improvement was observed through behavioural determinants such as cleaning obligation, cleaning ease, cleaning approval and affective beliefs.

CONCLUSION

Our study findings show that group discussions and commitment interventions derived from RANAS model of behaviour change are effective in improving the shared sanitation users' cleaning behaviour.

Shared toilet users' collective cleaning and determinant factors in Kampala slums, Uganda

Background

Dirty shared toilets are a health risk to users in urban slum settlements. For health and non-health benefits among users of shared toilets to be guaranteed, their cleanliness is important. The objective of this study was to investigate the cleanliness situation of shared toilets in Kampala’s slums and the psychological and social dilemma factors influencing users’ cleaning behaviour and commitment by using the risks, attitudes, norms, ability and self-regulation (RANAS) model and factors derived from the social dilemma theory.

Methods

We conducted a cross-sectional study in three slums of Kampala between December 2012 and January 2013. Data were collected from 424 household respondents that were primarily using shared toilets. Semi-structured questionnaires administered through face-to-face interviews were used in data collection. Linear regression was done for the multivariate analysis to test for the association between respondent cleaning behaviour and a combination of RANAS and social dilemma predictors.

Results

Out of 424 respondents interviewed, 44.3% reported cleaning the shared toilet daily, 34.4% cleaned once or several times a week, 1.4% cleaned every second week, 5.4% cleaned once or several times a month and 14.4% did not participate in cleaning. The main RANAS factors significantly associated with respondents’ cleaning behaviour were: attitudinal affective belief associated with cleaning a shared toilet (β = −0.13, P = 0.00) and self-regulating factors, such as coping planning (β = 0.42, P = 0.00), commitment (β = 0.24, P = 0.00), and remembering (β = 0.10, P = 0.01). For social dilemma factors, only the social motive factor was statistically significant (β = 0.15, P = 0.00). The R square for the linear model on factors influencing cleaning behaviour was 0.77 and R square for factors influencing cleaning commitment was 0.70.

Conclusion

The RANAS factors provide a more robust understanding of shared toilet users’ cleaning behaviour than social dilemma factors. Self-regulating factors and changing the negative affective cleaning feelings are shown to be very important for interventions to increase shared toilet users’ collective participation in their cleaning. In addition to RANAS, social dilemma factors have an important influence on slum residents’ commitment to clean their shared toilets.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-1260) contains supplementary material, which is available to authorized users.

Ecological sanitation coverage and factors affecting its uptake in Kabale municipality, western Uganda

Ecological sanitation (Ecosan) is a relatively new concept being promoted in many developing countries to improve sanitation coverage and recycle nutrients in excreta for agricultural production. We conducted a cross-sectional study in Kabale municipality, western Uganda to determine the coverage of Ecosan and factors affecting its uptake. A total of 806 respondents were interviewed, randomly selected from 32 of 77 (42%) villages in Kabale municipality. We held six focus group discussions and 10 key informant interviews. Ecosan coverage was found to be 20% (163/806). The factors that were significantly associated with Ecosan coverage included education, occupation, religion and age. Our study found a relatively high Ecosan coverage in Kabale municipality compared to the targeted national coverage of 15% by 2018. Policy-makers and organizations in Ecosan development ought to take into consideration the influence of education and socio-economic factors for successful uptake of ecological sanitation.