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 11 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.

­Description of the targeted water supply and hygiene response strategy implemented during the cholera outbreak of 2017-2018 in Kinshasa, DRC

Background: Rapid control of cholera outbreaks is a significant challenge in overpopulated urban areas. During late-2017, Kinshasa, the capital of the Democratic Republic of the Congo, experienced a cholera outbreak that showed potential to spread throughout the city. A novel targeted water and hygiene response strategy was implemented to quickly stem the outbreak.Methods: We describe the first implementation of the cluster grid response strategy carried out in the community during the cholera outbreak in Kinshasa, in which response activities targeted cholera case clusters using a grid approach. Interventions focused on emergency water supply, household water treatment and safe storage, home disinfection and hygiene promotion. We also performed a preliminary community trial study to assess the temporal pattern of the outbreak before and after response interventions were implemented. Cholera surveillance databases from the Ministry of Health were analyzed to assess the spatiotemporal dynamics of the outbreak using epidemic curves and maps.Results: From January 2017 to November 2018, a total of 1,712 suspected cholera cases were reported in Kinshasa. During this period, the most affected health zones included Binza Météo, Limeté, Kokolo, Kintambo and Kingabwa. Following implementation of the response strategy, the weekly cholera case numbers in Binza Météo, Kintambo and Limeté decreased by an average of 57% after two weeks and 86% after four weeks. The total weekly case numbers throughout Kinshasa Province dropped by 71% four weeks after the peak of the outbreak.Conclusion: During the 2017-2018 period, Kinshasa experienced a sharp increase in cholera case numbers. To contain the outbreak, water supply and hygiene response interventions targeted case households, nearby neighbors and public areas in case clusters using a grid approach. Following implementation of the response, the outbreak in Kinshasa was quickly brought under control. A similar approach may be adapted to quickly interrupt cholera transmission in other urban settings.

Description of the targeted water supply and hygiene response strategy implemented during the cholera outbreak of 2017-2018 in Kinshasa, DRC

Background Rapid control of cholera outbreaks is a significant challenge in overpopulated urban areas. During late-2017, Kinshasa, the capital ofthe Democratic Republic of the Congo, experienced a cholera outbreak that showed potential to spread throughout the city. A novel targeted water and hygiene response strategy was implemented to quickly stem the outbreak. Methods We describe the first implementation of the cluster grid response strategy carried out in the community during the cholera outbreak in Kinshasa, in which response activities targeted cholera case clusters using a grid approach. Interventions focused on emergency water supply, household water treatment and safe storage, home disinfection and hygiene promotion. We also performed a preliminary community trial study to assess the temporal pattern of the outbreak before and after response interventions were implemented. Cholera surveillance databases from the Ministry of Health were analyzed to assess the spatiotemporal dynamics of the outbreak using epidemic curves and maps. Results From January 2017 to November 2018, a total of 1,712 suspected cholera cases were reported in Kinshasa. During this period, the most affected health zones included Binza Météo, Limeté, Kokolo, Kintambo and Kingabwa. Following implementation of the response strategy, the weekly cholera case numbers in Binza Météo, Kintambo and Limeté decreased by an average of 57% after two weeks and 86% after four weeks. The total weekly case numbers throughout Kinshasa Province dropped by 71% four weeks after the peak of the outbreak. Conclusion During the 2017-2018 period, Kinshasa experienced a sharp increase in cholera case numbers. To contain the outbreak, water supply and hygieneresponse interventions targeted case households, nearby neighbors and public areas in case clusters using a grid approach. Following implementation of the response, the outbreak in Kinshasa was quickly brought under control. A similar approach may be adapted to quickly interrupt cholera transmission in other urban settings.

Description of the targeted water supply and hygiene response strategy implemented during the cholera outbreak of 2017-2018 in Kinshasa, DRC

Background Rapid control of cholera outbreaks is a significant challenge in overpopulated urban areas. During late-2017, Kinshasa, the capital of the Democratic Republic of the Congo, experienced an increase in cholera cases that showed potential to spread throughout the city. A novel targeted water and hygiene response strategy was implemented to quickly stem the outbreak. Methods We describe the first implementation of the cluster grid response strategy carried out in the community during the cholera outbreak in Kinshasa, in which water and hygiene response activities targeted cholera case clusters. Interventions, which focused on emergency water supply, household water treatment and safe storage, home disinfection and hygiene promotion, were organized using a grid approach. We also performed a preliminary community trial study to assess the temporal pattern of the outbreak, before and after response interventions were implemented. Cholera surveillance databases from the Ministry of Health were analyzed to assess the spatiotemporal dynamics of the outbreak using epidemic curves and cartography. Results From January 2017 to November 2018, a total of 1,712 suspected cholera cases were reported in Kinshasa. During this period, the health zones most affected included Binza Météo, Limeté, Kokolo, Kintambo and Kingabwa. Following implementation of the response strategy, the weekly cholera case numbers in Binza Météo, Kintambo and Limeté decreased by an average of 57% in two weeks and 86% in four weeks. The total weekly case numbers throughout Kinshasa Province dropped by 71% at four weeks after the outbreak peak. Conclusion During the 2017-2018 period, Kinshasa experienced a sharp increase in cholera cases that showed potential to rapidly spread throughout the city. To contain the outbreak, water and hygiene response interventions targeted case households, nearby neighbors and public areas in case clusters using a grid approach. Following implementation of the response, the outbreak in Kinshasa was quickly brought under control. A similar approach may be useful to quickly interrupt cholera transmission in other urban settings.

Multiscale analysis of a non-periodic epidemic time series using wavelet transform

SummaryThe aim of the present study was to develop a method for multiscale analysis of non-stationary and non-periodic epidemic time series. Indeed, the epidemiologists may need to know the features, at different resolutions, of short duration outbreaks that did not exhibit periodic cycles. Among of the large number of wavelets, we have developed a continuous wavelet that shows an analogous shape to the Haar wavelet, and leads to precise time localization. We applied the wavelet transform to the cholera epidemic, which began in October 2010 in Haiti. We determined the wavelet spectra of both the cholera case toll and rainfall time series, from September 01, 2010, to November 20, 2012 (812 days). The relationship between case toll and rainfall was analyzed using cross-wavelet spectra at different lags. Cholera case toll scalogram highlighted four epidemic bursts. Cross-wavelet analysis highlighted an absence of relationship between the first epidemic burst and rainfall, but a clear relationship between the following epidemic bursts and rainfall after a 3 to 8 day lag.

Interpretation of Article VIII, Section 29 of the Convention on the Privileges and Immunities of the UN

In 2013, a suit was lodged before the US District Court in NY, invoking UN responsibility for the outbreak of cholera in Haiti. The outbreak is a tragedy not only because of its catastrophic consequences but because it was caused by the UN peacekeeping operation. To date, however, the merits of the claims have never been examined due to UN immunity. While the UN Charter provides for this immunity in an equivocal manner, the specification by the CPIUN allows for a straightforward determination of its content and scope. In contrast, section 29 of the CPIUN , which stipulates the UN’s obligation to provide alternative means for dispute settlement as a counterpart of its immunity, is an interpretative puzzle. Due to discrepancies over the interpretation of the provision, the Haiti cholera case has resulted in a stalemate. Against this backdrop, the present study aims to clarify the content and scope of the obligation.