Africa Epidemic Service Fellow
Africa Centres for Disease Control and Prevention, Zambia
Abstract:
Background: Cholera remains a recurrent public health challenge in Zambia, causing repeated outbreaks with substantial morbidity and mortality, particularly in areas with inadequate water, sanitation, and hygiene (WASH) infrastructure. Recent large-scale outbreaks and the resurgence of cholera have highlighted the need for robust epidemiological evidence to inform evidence-based public health decision-making. Understanding the spatial and temporal distribution of cholera burden is essential for identifying transmission hotspots, strengthening preparedness and response, prioritizing surveillance, and targeted interventions, and guiding the efficient allocation of limited public health resources. This study analyzed national cholera surveillance data from 2020–2024 to characterize temporal trends, geographic distribution, and population-level burden and to generate evidence to inform cholera prevention, preparedness, and response strategies in Zambia.
Methods: A retrospective descriptive epidemiological study was conducted using routinely collected aggregated cholera surveillance data reported between 1 January 2020 and 31 December 2024. The study included all confirmed cholera cases reported through Zambia’s national surveillance system across all 10 provinces. Data were aggregated at district, provincial, and national levels. Data cleaning included standardization of district names, verification of records, and assignment of province identifiers. Descriptive analyses were performed to summarize annual and cumulative cases, deaths, incidence, and case fatality ratios (CFRs). Cumulative incidence was calculated using the average population for 2020–2024 as the denominator and expressed per 100,000 population. Temporal trends were illustrated using line graphs, while geographic variation was assessed using choropleth maps. Data management and statistical analyses were conducted using Microsoft Excel, and spatial analyses were performed using QGIS.
Results: Between 2020 and 2024, Zambia reported 24,562 confirmed cholera cases and 614 deaths, corresponding to an overall CFR of 2.5%. Cholera activity remained low during 2020–2022, with only 89 reported cases and two deaths, before increasing sharply to 4,042 cases and 115 deaths in 2023 and peaking at 20,431 cases and 497 deaths in 2024. Lusaka Province experienced the greatest burden, reporting 17,484 cases and 416 deaths, with a cumulative incidence of 564 cases per 100,000 population and a CFR of 2%. Considerable geographic heterogeneity was observed across provinces, with Luapula and Western provinces recording the lowest cumulative incidence. Population-adjusted analyses identified important differences in disease burden that were not evident from case counts alone, highlighting high-risk geographic hotspots.
Conclusion: The findings demonstrate a marked resurgence of cholera in Zambia during 2023–2024 following several years of relatively low transmission and reveal substantial geographic variation in disease burden. The persistently elevated CFR indicates continued challenges in timely case detection and management during outbreaks. Routine analysis of surveillance data strengthened surveillance systems, hotspot-targeted interventions, improved WASH investments, enhanced case management capacity, and strategic preparedness in high-risk districts should be prioritized to reduce cholera transmission and mortality and strengthen evidence-based public health decision making.
Biography:
Mamawah Diamond Bility is a Field Epidemiologist specializing in infectious disease research and outbreak response. She holds a Master of Science degree in Public Health, Epidemiology from Cuttington University in Liberia. Mamawah works with the National Public Health Institute of Liberia as a Field Epidemiologist and Public Health Emergency Operations Center Regional Coordinator. She is currently with the Africa Centres for Disease Control and Prevention as a fellow of the Africa Epidemic Service Fellowship and is assigned in Zambia at the National Public Health Institute.
