Micro-Hotspots of Risk in Urban Cholera Epidemics.

Andrew S Azman,David Olson,Justin Lessler,Bansaga Saga,Francisco J Luquero,Louis Albert Massing,Flavio Finger,Ngandwe Adalbert,Enrico Bertuzzo,Nathan Naibei Mbaïbardoum,Henrik Salje,Brahima Toure,Mohammad Ali,Klaudia Porten,Romain Ramazani,Jerome Leglise,Maya Allan

doi:10.1093/infdis/jiy283

Abstract

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 living closest to cases and diminished in time and space similarly across settings. These results provide a rational basis for rapidly delivering targeting interventions.

Highlights

Background t Cholera epidemics in subSaharan Africa produce a large proportion of global cholera-mortality and continue to wreak havoc on already fragile nations(1,2)
In Kalemie, DRC, household coordinates were successfully recorded for 1,077 of 1,146 suspected cholera cases reporting to the main diarrhea treatment center from January-2013 through January-2014
At 150m from the primary case household the elevated risk period does not start until 2-3 days after case presentation it still ends by day 5-6 (Figure 2). These results reveal similar spatiotemporal patterns of cholera cases across epidemics in two African cities

Summary

Introduction

Background t Cholera epidemics in subSaharan Africa produce a large proportion of global cholera-mortality and continue to wreak havoc on already fragile nations(1,2). Targeting cholera interventions to transmission hotspots, or areas of ip elevated transmission intensity in urban areas may be the best control strategy when resources are r constrained(3,4). Rapid response teams have been proposed as an important way to fight cholera in cholera prone countries. These teams can quickly provide emergency water, sanitation and hygiene interventions c (e.g., point-of-use water treatment and basic hygiene educational materials), and sometimes oral cholera vaccine to s neighbors of cholera cases(5,6). Nu Cholera transmission is thought to occur through two modes of exposure:(1) environmentally-mediated exposure, a often due to fecal contamination in the broader environment, and (2) “direct” exposure to an infected individual (e.g., being served food directly contaminated by a case)(7).

Methods

Results

Conclusion