SPATIAL EPIDEMIOLOGY OF CHOLERA IN KENYA: AN EIGHT-YEAR ANALYSIS OF OUTBREAK DISTRIBUTION FROM 2015 TO 2023

Abstract

Background: Cholera hotspot mapping is critical in the prioritization of interventions to cholera outbreaks in various settings. This study aimed to map cholera hotspots in Kenya between 2015 and 2023.
Methods: The study used a descriptive cross-sectional design using the National Cholera case linelist and bacterial culture and serology of Vibrio cholerae obtained from the National Public Health Laboratory. Cholera cases were mapped using ArcGIS pro to generate cholera hotspots on the basis of Mean Annual Incidence (MAI) and persistence.
Results: A total of 42,850 cholera cases were line listed with Nairobi County bearing the highest burden (24.8%) while Garissa county showed the highest Mean Annual Incidence (MAI) (163.8/100,000). The five high burden counties, are; Nairobi, Garissa, Wajir, Mandera and Tana River, accounting for 63.4% (27,169) of all the cases. Spatial and temporal analysis of the cholera outbreak, further identified Dadaab, Embakasi East, Embakasi West and Kibra as high priority sub-counties. Significant temporal variation in incidence was observed
with 2015 and 2022 having the highest MAI while no cases were reported in 2019 and 2021. Majority of cholera patients who succumbed to cholera were male (67.6%) (χ2 = 19.734, df=1, p< 0.001). Furthermore, age was significantly associated with vital status with the mean age of cholera patients who died being higher than that of the survivors (p<0.05).
Conclusion: This study highlights the importance of spatial analysis in
identifying cholera hotspots to guiding targeted interventions. The study recommends periodic cholera hotspot mapping and enhanced cholera surveillance to guide prioritization of key preventive strategies or interventions.