Impact of Climate Change, Conflict and COVID-19 Pandemic on Spatial and Temporal Trend of Cholera Outbreaks in Yobe State, Northeast Nigeria
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Background
Yobe State in Northeast Nigeria has been affected by protracted armed conflict, leading to a weakened health system and population displacement. The emergence of the COVID-19 pandemic in 2020 and recent recurrent seasonal flooding have further compounded the region’s vulnerabilities. These overlapping crises created favourable conditions for cholera transmission. Despite multiple outbreaks, the epidemiology of cholera within this complex context remains poorly documented. This study examines the epidemiological burden, spatial patterns, and temporal trends of cholera outbreaks in the state from 2020 to 2024.
Methodology
We conducted a retrospective cross-sectional study using cholera surveillance data from 2020 to 2024. Socio-demographic characteristics, temporal trends, and spatial patterns were analyzed. Spatial autocorrelation (Global Moran’s I), Local Indicators of Spatial Association (LISA), and Hotspot Analysis (Getis-Ord Gi*) were used to assess geographic clustering of cholera incidence across wards and Local Government Areas (LGAs).
Results
A total of 6,792 cholera cases and 178 deaths were reported during the study period, with an overall case fatality rate (CFR) of 2.6%. The largest outbreak occurred in 2021 (3,973 cases [58.5%]), followed by 2022 (2,297 cases [33.8%]), and least in 2024 (522 cases [7.7%]). Cholera incidences peaked during the rainy season, particularly in August. The overall mean age was 24.4 ± 17.3 years, with a slight female preponderance (52.3%). Mortality was highest among individuals aged above 60 years (CFR, 6.7%). Global Moran’s I revealed statistically significant spatial clustering (p < 0.01). LISA and Getis-Ord Gi* analyses identified persistent hotspots in densely populated and flood-prone, urban and peri-urban settlements.
Conclusion
Yobe State experienced a considerable burden of cholera in recent years, driven by conflict, population displacement, seasonal flooding, and post-COVID-19 pandemic challenges. Findings from this study suggest that strengthening Water Sanitation and Hygiene (WASH) infrastructure, enhancing surveillance, and integrating cholera control into broader humanitarian responses are critical in reducing future outbreaks.
