Case-area targeted interventions during a large-scale cholera epidemic: A prospective cohort study in Northeast Nigeria.

BACKGROUND: Cholera outbreaks are on the rise globally, with conflict-affected settings particularly at risk. Case-area targeted interventions (CATIs), a strategy whereby teams provide a package of interventions to case and neighboring households within a predefined "ring," are increasingly employed in cholera responses. However, evidence on their ability to attenuate incidence is limited. METHODS AND FINDINGS: We conducted a prospective observational cohort study in 3 conflict-affected states in Nigeria in 2021. Enumerators within rapid response teams observed CATI implementation during a cholera outbreak and collected data on household demographics; existing water, sanitation, and hygiene (WASH) infrastructure; and CATI interventions. Descriptive statistics showed that CATIs were delivered to 46,864 case and neighbor households, with 80.0% of cases and 33.5% of neighbors receiving all intended supplies and activities, in a context with operational challenges of population density, supply stock outs, and security constraints. We then applied prospective Poisson space-time scan statistics (STSS) across 3 models for each state: (1) an unadjusted model with case and population data; (2) an environmentally adjusted model adjusting for distance to cholera treatment centers and existing WASH infrastructure (improved water source, improved latrine, and handwashing station); and (3) a fully adjusted model adjusting for environmental and CATI variables (supply of Aquatabs and soap, hygiene promotion, bedding and latrine disinfection activities, ring coverage, and response timeliness). We ran the STSS each day of our study period to evaluate the space-time dynamics of the cholera outbreaks. Compared to the unadjusted model, significant cholera clustering was attenuated in the environmentally adjusted model (from 572 to 18 clusters) but there was still risk of cholera transmission. Two states still yielded significant clusters (range 8-10 total clusters, relative risk of 2.2-5.5, 16.6-19.9 day duration, including 11.1-56.8 cholera cases). Cholera clustering was completely attenuated in the fully adjusted model, with no significant anomalous clusters across time and space. Associated measures including quantity, relative risk, significance, likelihood of recurrence, size, and duration of clusters reinforced the results. Key limitations include selection bias, remote data monitoring, and the lack of a control group. CONCLUSIONS: CATIs were associated with significant reductions in cholera clustering in Northeast Nigeria despite operational challenges. Our results provide a strong justification for rapid implementation and scale-up CATIs in cholera-response, particularly in conflict settings where WASH access is often limited.

Water, Sanitation, and Cholera in Sub-Saharan Africa.

Improvements in water and sanitation should reduce cholera risk though the associations between cholera and specific water and sanitation access measures remain unclear. We estimated the association between eight water and sanitation measures and annual cholera incidence access across sub-Saharan Africa (2010-2016) for data aggregated at the country and district levels. We fit random forest regression and classification models to understand how well these measures combined might be able to predict cholera incidence rates and identify high cholera incidence areas. Across spatial scales, piped or "other improved" water access was inversely associated with cholera incidence. Access to piped water, septic or sewer sanitation, and septic, sewer, or "other improved" sanitation were associated with decreased district-level cholera incidence. The classification model had moderate performance in identifying high cholera incidence areas (cross-validated-AUC 0.81, 95% CI 0.78-0.83) with high negative predictive values (93-100%) indicating the utility of water and sanitation measures for screening out areas that are unlikely to be at high cholera risk. While comprehensive cholera risk assessments must incorporate other data sources (e.g., historical incidence), our results suggest that water and sanitation measures could alone be useful in narrowing the geographic focus for detailed risk assessments.

Longitudinal borehole functionality in 15 rural Ghanaian towns from three groundwater quality clusters.

OBJECTIVE: In sub-Saharan Africa, 45% of the rural population uses boreholes (BHs). Despite recent gains in improved water access and coverage, parallel use of unimproved sources persists. Periodic infrastructure disrepair contributes to non-exclusive use of BHs. Our study describes functionality of BHs in 2014, 2015, and 2016 in 15 rural towns in the Eastern Region of Ghana sourced from three groundwater quality clusters (high iron, high salinity, and control). We also assess factors affecting cross-sectional and longitudinal functionality using logistic regression. RESULTS: BH functionality rates ranged between 81 and 87% and were similar across groundwater quality clusters. Of 51 BHs assessed in all three years, 34 (67%) were consistently functional and only 3 (6%) were consistently broken. There was a shift toward proactive payment for water over the course of the study in the control and high-salinity clusters. Payment mechanism, population served, presence of nearby alternative water sources, and groundwater quality cluster were not significant predictors of cross-sectional or longitudinal BH functionality. However, even in the high iron cluster, where water quality is poor and no structured payment mechanism for water exists, BHs are maintained, showing that they are important community resources.

Case-area targeted preventive interventions to interrupt cholera transmission: Current implementation practices and lessons learned.

BACKGROUND: Cholera is a major cause of mortality and morbidity in low-resource and humanitarian settings. It is transmitted by fecal-oral route, and the infection risk is higher to those living in and near cholera cases. Rapid identification of cholera cases and implementation of measures to prevent subsequent transmission around cases may be an efficient strategy to reduce the size and scale of cholera outbreaks. METHODOLOGY/PRINCIPLE FINDINGS: We investigated implementation of cholera case-area targeted interventions (CATIs) using systematic reviews and case studies. We identified 11 peer-reviewed and eight grey literature articles documenting CATIs and completed 30 key informant interviews in case studies in Democratic Republic of Congo, Haiti, Yemen, and Zimbabwe. We documented 15 outbreaks in 12 countries where CATIs were used. The team composition and the interventions varied, with water, sanitation, and hygiene interventions implemented more commonly than those of health. Alert systems triggering interventions were diverse ranging from suspected cholera cases to culture confirmed cases. Selection of high-risk households around the case household was inconsistent and ranged from only one case to approximately 100 surrounding households with different methods of selecting them. Coordination among actors and integration between sectors were consistently reported as challenging. Delays in sharing case information impeded rapid implementation of this approach, while evaluation of the effectiveness of interventions varied. CONCLUSIONS/SIGNIFICANCE: CATIs appear effective in reducing cholera outbreaks, but there is limited and context specific evidence of their effectiveness in reducing the incidence of cholera cases and lack of guidance for their consistent implementation. We propose to 1) use uniform cholera case definitions considering a local capacity to trigger alert; 2) evaluate the effectiveness of individual or sets of interventions to interrupt cholera, and establish a set of evidence-based interventions; 3) establish criteria to select high-risk households; and 4) improve coordination and data sharing amongst actors and facilitate integration among sectors to strengthen CATI approaches in cholera outbreaks.

Lessons learned from conducting six multi-country mixed-methods effectiveness research studies on water, sanitation, and hygiene (WASH) interventions in humanitarian response.

BACKGROUND: Provision of safe water, sanitation, and hygiene (WASH) to affected populations in humanitarian emergencies is necessary for dignity and communicable disease control. Additional evidence on WASH interventions is needed in humanitarian settings. Between 2008 and 2019, we completed six multi-country, mixed-methods effectiveness studies in humanitarian response on six different WASH interventions. In each evaluation, we conducted: key informant interviews; water point observations and water quality testing; household surveys with recipients, including survey and water quality testing; focus group discussions; and/or, secondary data analysis. The research questions were: "What is the effectiveness of [intervention] in reducing the risk of diarrhea/cholera transmission; and, what programmatic factors lead to higher effectiveness?" DISCUSSION: In all six multi-country, mixed-methods evaluations, policy-relevant outcomes were obtained. We found, in our individual research results, that: interventions could reduce the risk of disease in humanitarian contexts; this reduction of risk did not always occur, as there were large ranges in effectiveness; and, implementation factors were crucial to intervention effectiveness. When collaboratively reviewing our research process across evaluations, we found strategies for successfully conducting this research included: 1) working with partners to identify and evaluate programs; 2) rapidly obtaining approvals to deploy; and, 3) conducting research methodologies consistently. Personal connections, in-person communication, trust, and experience working together were key factors for success in identifying partners for evaluation. Successes in evaluation deployment occurred with flexibility, patience, commitment of adequate time, and understanding of processes; although we note access and security concerns in insecure contexts precluded deployment. Consistent and robust protocols, flexibility, and a consistent researcher on the ground in each context allowed for methodological consistency and high-quality results. CONCLUSIONS: In conclusion, we have found multi-country, mixed-methods results to be one crucial piece of the WASH evidence base in humanitarian contexts. This is particularly because evaluations of reductions in risk from real-world programming are policy-relevant, and are directly used to improve programming. In future, we need to flexibly work with donors, agencies, institutions, responders, local governments, local responders, and beneficiaries to design safe and ethical research protocols to answer questions related to WASH interventions effectiveness in humanitarian response, and, improve WASH programming.

Fecal Indicator Bacteria Data to Characterize Drinking Water Quality in Low-Resource Settings: Summary of Current Practices and Recommendations for Improving Validity.

Fecal indicator bacteria (FIB) values are widely used to assess microbial contamination in drinking water and to advance the modeling of infectious disease risks. The membrane filtration (MF) testing technique for FIB is widely adapted for use in low- and middle-income countries (LMICs). We conducted a systematic literature review on the use of MF-based FIB data in LMICs and summarized statistical methods from 172 articles. We then applied the commonly used statistical methods from the review on publicly available datasets to illustrate how data analysis methods affect FIB results and interpretation. Our findings indicate that standard methods for processing samples are not widely reported, the selection of statistical tests is rarely justified, and, depending on the application, statistical methods can change risk perception and present misleading results. These results raise concerns about the validity of FIB data collection, analysis, and presentation in LMICs. To improve evidence quality, we propose a FIB data reporting checklist to use as a reminder for researchers and practitioners.

Effectiveness of water chlorination programs along the emergency-transition-post-emergency continuum: Evaluations of bucket, in-line, and piped water chlorination programs in Cox's Bazar.

Supplying safe drinking water in humanitarian emergencies is critical, and source water chlorination is a commonly implemented intervention to provide safe water. We evaluated three different source water chlorination programs (bucket, in-line, and piped water chlorination) in the ongoing humanitarian response in Cox's Bazar refugee camps in Bangladesh. We used a mixed-methods research protocol including key informant interviews, water point observations, focus group discussions, household surveys, and water quality testing. The three evaluated programs were implemented at different response stages and required different levels of staffing, infrastructure, and community mobilization work. In the bucket chlorination program, highly contaminated open well water was chlorinated, in in-line and piped water chlorination programs, groundwater was treated. Overall, 71% of bucket, 36% of in-line, and 60% of piped water chlorination households had stored water that met free chlorine residual (FCR) criteria, respectively. Additionally, 71% of bucket, 86% of in-line, and 91% of piped water chlorination households had stored water that met Escherichia coli (E. coli) criteria (<10 E. coli CFU/100 mL). Regression results indicate presence of FCR, serving water by pouring, and higher source water pH were associated with meeting E. coli criteria. Our results highlight: no individual program fully met international standards as implemented, although each partially met standards; the importance of understanding beneficiary preferences and behavior change campaigns; and, the benefits and drawbacks of each source water chlorination program must be considered before implementation. Overall, we found appropriate source water chlorination program choice is a continuum, depending on humanitarian phase and context. Therefore, we recommend continuing context- and phase-appropriate source water chlorination programs, emphasizing consistent and acceptable chlorine dosage, implementing programmatic improvements, and incorporating user preferences to reduce microbial contamination and consequently the risk of waterborne diseases.

Delivering Drinking Water by Truck in Humanitarian Contexts: Results from Mixed-Methods Evaluations in the Democratic Republic of the Congo and Bangladesh.

Water trucking is a commonly implemented, but severely under-researched, drinking water supply intervention in humanitarian response. To fill this research gap, we conducted three mixed-methods water trucking program evaluations in the Democratic Republic of the Congo and Bangladesh, including interviews, water point observations, household surveys, focus groups, and water quality testing. Results indicated that the programs had complex implementation structures involving multiple agencies and limited infrastructure to properly collect, treat, and deliver water. All programs met queueing time and distance indicators, did not meet water quantity indicators, and inconsistently met water quality indicators. Free chlorine residual (FCR) declined through the water chain, and household water Escherichia coli concentrations were associated with household FCR, receiving behavior change messages, storage container type, and distance from the distribution point. Users appreciated water trucking, especially compared to previous water sources, and expressed desires for increased quantity, improved quality, and consistent delivery. If water trucking programs are implemented, it is recommended to have the financial resources to install sanitary collection and distribution infrastructure, establish a management team of all implementation partners, ensure sufficient water quantity is delivered, ensure recommended FCR levels at distribution points, monitor FCR throughout distribution, and complete behavior change communication activities about the program and safe water storage with users.

Effectiveness of Multilevel Risk Management Emergency Response Activities To Ensure Free Chlorine Residual in Household Drinking Water in Southern Syria.

To provide safe drinking water and reduce the risk of disease, emergency responders in southern Syria are implementing a multilevel risk reduction strategy with the aim of ensuring free chlorine residual (FCR) in household drinking water. Responders implemented activities across the water chain (from chlorination station and well operators to water vendors to household members), including distribution of supplies for chlorination and training on chlorine use; activities varied by responder. We evaluated the effectiveness of these interventions in a cross-sectional observation study including interviews and observations with 24 chlorination station operators and 63 well owners/managers; interviews, observations, and water quality testing with 220 water truckers; and surveys and water quality testing with 1006 households. Across all responders, activities successfully ensured FCR in household drinking water (61-96% of households with FCR ≥ 0.1 mg/L compared to 21% in nonintervention households, p < 0.001). Centralized interventions led to the highest FCR results. Household FCR was associated with access to piped water systems (aOR 3.5, 95% CI 1.8-6.7) and chlorine distribution (aOR 6.1, 95% CI 3.4-11.0). We recommend continuing activities, emphasizing central-level activities, and supplementing with household-level activities. These results will help to optimize current interventions and guide future response design in similar contexts.

Water, sanitation, and hygiene access in southern Syria: analysis of survey data and recommendations for response.

BACKGROUND: Water, sanitation, and hygiene (WASH) are immediate priorities for human survival and dignity in emergencies. In 2010, > 90% of Syrians had access to improved drinking water. In 2011, armed conflict began and currently 12 million people need WASH services. We analyzed data collected in southern Syria to identify effective WASH response activities for this context. METHODS: Cross-sectional household surveys were conducted in 2016 and 2017 in 17 sub-districts of two governorates in opposition controlled southern Syria. During the survey, household water was tested for free chlorine residual (FCR). Descriptive statistics were calculated, and mixed effect logistic regressions were completed to determine associations between demographic and WASH variables with outcomes of FCR > 0.1 mg/L in household water and reported diarrhea in children < 5 years old. RESULTS: In 2016 and 2017, 1281 and 1360 surveys were conducted. Piped water as the main water source declined from 22.0% to 15.3% over this time. Households accessed 50-60 l per capita daily (primarily from private water trucking networks). Households spent ~ 20% of income on water and reported market-available hygiene items were unaffordable. FCR > 0.1 mg/L increased from 4.1% to 27.9% over this time, with Water Safety Plan (WSP) programming strongly associated with FCR (mOR: 24.16; 95% CI: 5.93-98.5). The proportion of households with childhood diarrhea declined from 32.8% to 20.4% over this time; sanitation and hygiene access were protective against childhood diarrhea. CONCLUSIONS: The private sector has effectively replaced decaying infrastructure in Syria, although at high cost and uncertain quality. Allowing market forces to manage WASH services and quantity, and targeting emergency response activities on increasing affordability with well-targeted subsidies and improving water quality and regulation via WSPs can be an effective, scalable, and cost-effective strategy to guarantee water and sanitation access in protracted emergencies with local markets.