Cholera in Africa: A Climate Change Crisis

Abstract

Background

Cholera, an acute diarrheal infection caused by Vibrio cholerae, remains a significant public health concern globally, with 1.4-4.0 million cases and 21,000-143,000 deaths annually. While the disease is endemic in 47 less-developed countries across Africa and Asia, the African continent has been particularly affected, with 19 of 29 countries reporting cases in 2023 being from Africa.

Aim

To explore the trend of cholera outbreaks in Africa and analyze how climate change has contributed to the spread of the disease in the continent.

Methods

A review of current cholera outbreaks in Africa, with particular focus on Sudan and Ethiopia as case studies, examining the relationship between climatic factors and cholera transmission.

Results

Recent outbreaks in Sudan (declared September 26, 2023) resulted in 5,414 suspected cases and 170 deaths (case fatality rate 3.1%) across nine states as of December 5, 2023. In Ethiopia’s Somali region, 772 confirmed cases and 23 deaths were reported within two weeks, with approximately 80% of cases affecting children. Climate factors significantly influence cholera transmission: a 1 °C temperature rise doubled cholera cases in Zanzibar. Both drought conditions, which increase Vibrio cholerae concentration in groundwater, and heavy rainfall periods, which lead to flooding and breakdown of sanitary conditions, contribute to outbreak risks.

Conclusions

Climate change impacts cholera transmission through rainfall patterns, temperature variations, and extreme weather events. Management recommendations include implementing accurate weather surveillance systems, strategic vaccination programs, flood-proof water supply infrastructure, and community engagement protocols. These interventions should be integrated while considering the growing influence of climate change on disease patterns.

Clinical Trial Number

Not applicable.

Introduction

Cholera, often referred to as the “blue death,” is an acute diarrheal infection caused by consuming food or water contaminated with the bacterium Vibrio cholerae. This communicable disease can lead to severe mortality, potentially resulting in death within hours of transmission if not treated promptly [1].

Cholera is one of the oldest known bacterial infections, with records of seven pandemics since the early 19th century. The seventh pandemic began in 1961 and continues to this day, primarily driven by the El Tor biotype of V. cholerae [2]. Worldwide, an estimate of 1.4–4.0 million cases of cholera and 21 000–143 000 mortalities have been documented annually. Currently, cholera is endemic to at least 47 developing countries, mainly within the continents of Africa and Asia [2].

Although interventions such as oral cholera vaccination (OCV), improved water sanitation, and proper hygiene practices have significantly reduced cholera morbidity and mortality, several emerging challenges threaten these gains. Climate change, characterized by rising temperatures, changing precipitation patterns, and extreme weather events, has been increasingly linked to cholera outbreaks by altering water ecosystems and increasing exposure risks [3]. Additionally, droughts, floods, humanitarian crises, political instability, and limited healthcare resources exacerbate cholera’s spread, particularly in African regions with fragile public health infrastructure [1, 4].

Given these challenges, this article aims to analyze the epidemiological trends of cholera outbreaks in Africa and examine how climate change influences the spread and severity of the disease across the continent.

The Current Cholera Outbreak in Africa

Cholera outbreaks have emerged as a significant global health concern, as highlighted by the World Health Organization (WHO), which reported cases in 29 countries since January 2023. Alarmingly, 19 of these countries are situated in Africa, a region particularly vulnerable due to high transmission rates. These rates are influenced by various factors, including climate change, extreme weather events, and fragile healthcare systems that exacerbate the spread of the disease [5].

A poignant example of this trend is the ongoing cholera outbreak in Sudan, which has severely impacted multiple states. As of December 23, 2023, Sudan has recorded 8,267 suspected cholera cases and 224 fatalities, resulting in a case fatality rate of 2.7%. Officially declared on September 26, 2023, in Gedaref, the outbreak has now spread to 46 localities across nine states. In response to this escalating crisis, the Sudanese Federal Ministry of Health, alongside the WHO, has launched robust efforts to combat the outbreak. This includes extensive vaccination campaigns, which have already reached over 2.2 million individuals, with ambitions to extend coverage to a total of 5.5 million people in 14 high-risk areas [6].

Ethiopia’s Somali region is currently experiencing a cholera outbreak, which has been aggravated by the region’s changing climate, characterized by extreme droughts and heavy rainfall. These weather shifts have contributed to water shortages during the dry season, followed by flooding and water contamination when rains return, both of which create conditions favorable for cholera transmission [7]. The Somali Regional State Health Bureau reported 772 confirmed cases of cholera and 23 deaths in just 2 weeks of the outbreak being established. In some of the worst affected areas, an estimated 80% of the affected population were children [8] (Figs. 1, 2, 3).

Fig. 1.

WHO AFRO Region Countries and their Cholera Report Status in the Multi−country Outbreak between 1 January to 31 December 2024. Source: Created using www.mapchart.net (User: Lydia Daniel Bisetegn) Country reports outlined on Map from Table of Cholera cases and deaths reported from WHO regions (AFRO Region has been isolated) [9, 10]

Fig. 2.

Cholera Cases and Deaths Reported from WHO AFRO Region 1 January to 31 December 2023. Source: Data sourced from Table of Cholera cases and deaths reported from WHO regions (AFRO Region has been isolated) [9]

Fig. 3.

Cholera Cases and Deaths Reported from WHO AFRO Region 1 January to 31 December 2024. Source: Data sourced from Table of Cholera cases and deaths reported from WHO regions (AFRO Region has been isolated) [10]

The Impact of Climate Change on the Current Cholera Epidemic in Africa

Climate change has emerged as a key driver of cholera outbreaks by altering environmental conditions that facilitate disease transmission. Factors such as heavy rainfall, rising sea surface temperatures, and El Niño events have significantly influenced cholera prevalence [11–13]. In Sudan and Ethiopia, recurrent droughts and extreme flooding have intensified water insecurity, forcing communities to depend on unsafe water sources. In Sudan, floods have displaced thousands, contaminating water supplies and increasing the risk of waterborne diseases. Meanwhile, Ethiopia’s prolonged droughts have led to greater reliance on infected water sources, contributing to rising cholera cases. (14, 15) Climate variability has also been linked to the resurgence of cholera in several African countries, including Malawi, Mozambique, Zimbabwe, Kenya, Somalia, the Democratic Republic of the Congo (DRC), Cameroon, and Nigeria [16–18].

Beyond water scarcity and contamination, climate change alters ecological conditions that favor the growth and persistence of Vibrio cholerae. In Zanzibar, a 1 °C increase in temperature was associated with a twofold rise in cholera cases, highlighting the direct impact of warming trends on disease spread [19]. Shifts in precipitation patterns also influence water salinity, creating optimal conditions for Vibrio cholerae to thrive. Additionally, extreme flooding worsens fecal-oral transmission by overwhelming sanitation systems and increasing human exposure to contaminated water. These climate-driven factors underscore the urgent need for integrated public health strategies, including improved water management, enhanced surveillance, and climate adaptation measures to curb cholera transmission [19–21].

Recommendations

Given the recent outbreak of cholera in Africa, several variables may be implicated in the increasing incidence of cholera. Endemic factors comprise low socioeconomic status, poor sanitation, limited access to clean drinking water and healthcare, and a dearth in education [22]. Global issues such as climate change further exacerbate the situation. Numerous changes could be implemented to help reduce disease burden on the population [23, 24].

Toxigenic Vibrio cholerae may colonize and persist on plastic waste for up to 18 days. Colonized plastics subsequently contaminate flood water, which constitutes a major issue of paramount importance during natural disasters (i.e., Cyclone Freddy February-March 2023) [21]. Accurate weather surveillance systems, such as atmospheric pressure and water level monitoring, could serve as cholera alerts. Additionally, updated climate maps [25] may also aid in the prediction of climate severity, employed as a guide for shunting resources.

Vaccination against Vibrio cholerae would also mitigate disease burden. With numerous outbreaks worldwide, the standard two-dose regimen for immunization was reduced to one dose only, which confers immunity against the bacteria for 6 months. Distribution of said vaccines should occur with risk stratification in mind. Additional vaccines may be administered when harsh climate conditions are anticipated [25, 26].

Flood-proof water supply lines are pivotal in these areas. Access to piped water, swerve sanitation, raised boreholes, and other water sanitation techniques were associated with decreased cholera incidence [27].

Finally, the importance of community involvement should not be understated; cholera treatment modalities should incorporate strategies in public health awareness and community engagement.Community members should be able to identify outbreaks promptly and predict potential endemics by using historical weather data [23].

Author Contributions

O.U: Conceptualization, Project administration, Writing-review and Designing. Manuscript writing: B.K.B; O.U; L.D.B; A.M; M.C; P.S; C.V.P.OO.U: Reviewed and edited the first draft B.K.B: Reviewed and edited the second draft. O.U: Reviewed and edited the final draft Final approval of manuscript: All authors (B.K.B; O.U; L.D.B; A.M; M.C; P.S; C.V.P.O). All co-authors approved the final manuscript. All co-authors have read and approved the submission.

Funding

We have not received any financial support for this manuscript.

Data Availability

No datasets were generated or analysed during the current study.

Declarations

Ethics Approval

Not applicable.

Consent for Publication

Not applicable.

Competing Interests

The authors declare no competing interests.

Financial Support

None.