Micro-Hotspots of Risk in Urban Cholera Epidemics.
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ABSTRACT:
SUBMITTER: Azman AS
PROVIDER: S-EPMC6107744 | biostudies-literature | 2018 Aug
REPOSITORIES: biostudies-literature
Publications
Micro-Hotspots of Risk in Urban Cholera Epidemics.
Azman Andrew S AS Luquero Francisco J FJ Salje Henrik H Mbaïbardoum Nathan Naibei NN Adalbert Ngandwe N Ali Mohammad M Bertuzzo Enrico E Finger Flavio F Toure Brahima B Massing Louis Albert LA Ramazani Romain R Saga Bansaga B Allan Maya M Olson David D Leglise Jerome J Porten Klaudia K Lessler Justin J
The Journal of infectious diseases 20180801 7
Targeted interventions have been delivered to neighbors of cholera cases in major epidemic responses globally despite limited evidence for the impact of such targeting. Using data from urban epidemics in Chad and Democratic Republic of the Congo, we estimate the extent of spatiotemporal zones of increased cholera risk around cases. In both cities, we found zones of increased risk of at least 200 meters during the 5 days immediately after case presentation to a clinic. Risk was highest for those ...[more]
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Project description:BACKGROUND:Planning interventions to respond to cholera epidemics requires an understanding of the major transmission routes. Interrupting short-cycle (household, foodborne) transmission may require different approaches as compared long-cycle (environmentally-mediated/waterborne) transmission. However, differentiating the relative contribution of short- and long-cycle routes has remained difficult, and most cholera outbreak control efforts focus on interrupting long-cycle transmission. Here we use high-resolution epidemiological and municipal infrastructure data from a cholera outbreak in 1853 Copenhagen to explore the relative contribution of short- and long-cycle transmission routes during a major urban epidemic. METHODOLOGY/PRINCIPAL FINDINGS:We fit a spatially explicit time-series meta-population model to 6,552 physician-reported cholera cases from Copenhagen in 1853. We estimated the contribution of long-cycle waterborne transmission between neighborhoods using historical municipal water infrastructure data, fitting the force of infection from hydraulic flow, then comparing model performance. We found the epidemic was characterized by considerable transmission heterogeneity. Some neighborhoods acted as localized transmission hotspots, while other neighborhoods were less affected or important in driving the epidemic. We found little evidence to support long-cycle transmission between hydrologically-connected neighborhoods. Collectively, these findings suggest short-cycle transmission was significant. CONCLUSIONS/SIGNIFICANCE:Spatially targeted cholera interventions, such as reactive vaccination or sanitation/hygiene campaigns in hotspot neighborhoods, would likely have been more effective in this epidemic than control measures aimed at interrupting long-cycle transmission, such as improving municipal water quality. We recommend public health planners consider programs aimed at interrupting short-cycle transmission as essential tools in the cholera control arsenal.
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