Causes of Cholera
Cholera is caused by infection with Vibrio cholerae. This gram-negative bacterium produces cholera toxin (CTX), which disrupts normal intestinal absorption and leads to massive fluid secretion.
The causes can be grouped into biological, environmental, and socio-economic factors:
1. Biological Cause
Pathogen: Vibrio cholerae serogroups O1 and O139 are the main causative agents. The bacterium colonises the small intestine and releases toxins that cause watery diarrhoea.
2. Environmental Causes
Contaminated Water Sources: Cholera is strongly linked to unsafe water supply. Drinking water contaminated with human faeces is the most common transmission route.
Contaminated Food: Eating raw or undercooked seafood (e.g., shellfish) from contaminated waters, or food prepared under unhygienic conditions, can spread the bacteria.
Seasonal And Climatic Factors: Heavy rains, flooding, and warm temperatures often trigger outbreaks, as they increase contamination of water supplies.
3. Socio-economic And Behavioural Causes
Poor Sanitation and Hygiene: Lack of proper toilets, sewage treatment, and waste disposal systems.
Overcrowding: Refugee camps, disaster zones, or urban slums often experience outbreaks due to inadequate sanitation.
Low Socio-economic Status: Poverty increases reliance on unsafe water and poor hygiene practices.
Human-to-Human Indirect Transmission: Although not spread by direct contact, infected individuals shed bacteria in stool, contaminating the environment and infecting others.
Symptoms Of Cholera
Cholera infection ranges from asymptomatic cases to life-threatening disease.
The severity depends on the strain, dose ingested, and host immunity.
1. Mild To Moderate Symptoms
- Mild diarrhoea (sometimes indistinguishable from other diarrheal diseases)
- Abdominal discomfort
- Low-grade dehydration
2. Severe Symptoms (Classical Cholera)
- Profuse “Rice-water” Diarrhoea: Sudden onset of painless, watery stools that look milky-white.
- Vomiting: Often without nausea.
- Rapid Dehydration: Occurs within hours; signs include:
- – Dry mouth and extreme thirst
- – Sunken eyes and reduced skin turgor
- – Cold, clammy skin
- – Electrolyte Imbalance: Leads to painful muscle cramps, restlessness, and weakness.
- – Circulatory Collapse (Hypovolemic Shock): Low blood pressure, rapid, weak pulse.
- Severe Cases: If untreated, death can occur within 6–12 hours due to dehydration and shock
3. Complications
- Acute kidney injury (from reduced blood flow)
- Seizures (from electrolyte imbalance, especially in children)
- Coma and death in untreated severe cases
Latest Cholera Prevalence In Nigeria
Mid-2024 Outbreak:
- Between January and September 2024, Nigeria recorded 7,056 suspected cases of cholera and 204 deaths, with a case fatality rate (CFR) of 2.9% across all 36 states. Lagos accounted for approximately 60% of the suspected cases, while Bayelsa, Katsina, Zamfara, and Ebonyi also saw high numbers (Adebajo et al., 2025).
Peak Occurrence And Regional Impact:
- The outbreak peaked in June and July 2024, with 2,511 suspected cases in June (CFR ~3.9%) and 2,016 cases in July. By August, cases declined to 1,197, and the CFR improved to 2.4%. Some states, like Rivers, Zamfara, and Imo, reported higher CFRs (7.8%, 6.7%, and 5.7%, respectively) (Adebajo et al., 2025).
Early 2025 Data:
- From January 1 to May 25, 2025, 1,562 cholera cases were reported in Nigeria, including 48 deaths. However, WHO has cautioned that these figures may significantly underreport the full extent of the outbreak due to surveillance and reporting challenges (Adejoro, 2025)
2025 Mid-Year Surge:
- As of July 28, 2025, the outbreak situation escalated further, with 4,700 reported cholera cases, 113 deaths, and a CFR of 2.4%. These are concentrated in flood-affected and displaced communities (WHO, 2025).
- In Nigeria in 2025, the prevalence of cholera has shown a significant increase compared to previous years. As of early March 2025 (epi week 9), there were 1,149 suspected cases reported from 25 states with 28 deaths, resulting in a case fatality ratio (CFR) of 2.4%. The state of Bayelsa alone reported 763 cases (66% of the total), with the Southern Ijaw LGA accounting for 20% of all suspected cases. Nationwide, cholera cases have increased by 2% compared to the same period in 2024, while deaths have surged by 75% in 2025. Earlier in the year (epi week 5), 886 suspected cases and 14 deaths were reported from 22 states, with Bayelsa state accounting for 78% of cases. In the first quarter of 2025, Nigeria recorded 1,227 cholera cases and 28 deaths, contributing significantly to the African region’s cholera burden (NCDC, 2025). The overall context indicates a persistent and concerning cholera outbreak in Nigeria in 2025, with multiple states affected and a heightened case fatality ratio
Prevention Of Cholera
1. Avoid contaminated water; use treated water.
2. Practice hand hygiene and sanitation. Wash your hands frequently with soap and clean running water, and use alcohol-based hand sanitiser if soap and clean water are not available.
3. Make sure foods are well-cooked and keep utensils and food storage areas clean. Ensure that food is well-cooked before consumption. Avoid raw food such as fruits and vegetables, except you have washed them in safe water or peeled them yourself.
4. There should be prompt reporting of cholera cases to prevent an outbreak.
5. Train locals and health workers on the importance of adhering to preventive measures.
6. There should be adequate treatment access and rehydration in severe cases.
7. Administration of cholera vaccine
8. Avoid open defecation, indiscriminate refuse dumping and ensure proper disposal of waste and frequent clearing of sewage.
Epidemiology Of Cholera
- Cholera is an acute diarrheal disease caused by ingestion of food or water contaminated with Vibrio cholerae, particularly serogroups O1 and O139. It remains a global public health threat, particularly in low- and middle-income countries, where access to safe drinking water, adequate sanitation, and proper hygiene practices is limited.
- Geographic distribution: Cholera is endemic in parts of Africa, South Asia, and Southeast Asia, with periodic outbreaks in the Middle East and Latin America. Sub-Saharan Africa currently reports the highest burden.
- Transmission: It spreads via the faecal-oral route, often linked to poor sanitation, unsafe water supplies, and overcrowded conditions.
- Seasonality: In endemic regions, cholera outbreaks often show seasonal peaks, frequently coinciding with rainy seasons or flooding.
- At-risk populations: Children under 5 years, displaced populations (refugees, internally displaced persons), and individuals in urban slums are disproportionately affected.
Burden Of Cholera
The disease continues to cause significant morbidity and mortality worldwide:
- Global burden: The World Health Organisation (WHO) estimates that 1.3 to 4 million cholera cases occur annually, with 21,000 to 143,000 deaths worldwide.
- Underreporting: The true burden is likely higher due to underdiagnosis and weak surveillance in endemic countries.
- Health system strain: During outbreaks, cholera rapidly overwhelms fragile health systems, causing high case fatality rates if untreated.
- Socio-economic impact: Beyond health, cholera affects livelihoods by reducing productivity, straining health budgets, and disrupting trade and travel.
- Prevention gap: Despite being preventable through safe water, sanitation, hygiene (WASH), and vaccination, cholera persists as a disease of inequity, disproportionately affecting marginalised communities.
WASH (Water, Sanitation, and Hygiene)
WASH (Water, Sanitation, and Hygiene) is a critical public health approach addressing three interconnected components essential for human survival and development.
Current Global Status
- 663 million people lack improved drinking water sources
- 673 million people still practice open defecation
- Only 19% of people worldwide wash their hands after contact with excreta
- Two out of five people lack adequate handwashing facilities
Key Health Impacts
WASH directly affects child mortality through diarrheal diseases, malnutrition, and infections. Poor WASH conditions contribute to maternal mortality, childhood stunting, and various neglected tropical diseases.
Recent Research Focus
- Implementation science to bridge knowledge-practice gaps
- Integration with nutrition and gender equity programs
- Innovative assessment tools for measuring hygiene practices
- Microbiome research linking water quality to gut health
Major Challenges
- Significant rural-urban disparities in access
- Climate change and environmental degradation
- Weak governance and institutional capacity (especially in Sub-Saharan Africa)
- Financial sustainability of interventions
Global Goals And Solutions
- UN SDG 6: Universal water/sanitation access by 2030
- Innovative financing: Microfinance and group saving approaches
- Integrated programs: Combining WASH with housing, nutrition, and health
- Public-private partnerships for sustainable service delivery
Regional Example: Nigeria
Traditional birth homes operate under poor WASH conditions, contributing to maternal/newborn infections. The USAID E-WASH program addresses urban slum conditions through community partnerships and infrastructure development.
Policy And Governance
- Institutional arrangements and governance mechanisms require clear leadership structures, robust institutional arrangements, stakeholder engagement frameworks, and mechanisms for monitoring, localisation, and partnerships. It also emphasises five key governance priorities, including effective institutions, integrated policies, innovation, evidence-based decision-making, and youth empowerment.
- Policy Coherence, Legislation and Localisation reviews emphasise the institutionalisation of SDGs into national legislation. Examples include Austria’s integration of the SDGs into its constitutional environmental and animal protection laws, Pakistan’s establishment of a dedicated parliamentary SDG Unit, and the production of over 260 Voluntary Local Reviews (VLRs) since 2018, demonstrating an increasing but uneven commitment.
- Financing and Global Governance Alignment emphasises raising domestic tax revenue to at least 15% of GDP, tripling multilateral development bank (MDB) lending, introducing levies (e.g., a premium air-travel tax), and reinforcing corporate governance through transparency, sustainability reporting, and public-private partnerships. Emphasis was also made on policy coherence for development (PCSD), ODA targets, Global Gateway alignment, and reform of the international financial architecture.
- Governance—Transparency, Anti-Corruption & Capacity Building focuses on improving corporate governance through transparency and the use of responsible financial instruments, such as sustainability-linked bonds, as recognised in SDG 16 (Peace, Justice, and Strong Institutions).
- Youth and Multi-Stakeholder Engagement focuses on empowering youth by promoting youth-informed, youth-advisory councils, digital literacy, policy inclusion, and cross-sector partnerships, as outlined in SDGs 16 and 17. It exemplifies how civil society partnerships can enhance data systems and accountability. Broader stakeholder inclusion, encompassing civil society, local governments, women, and indigenous peoples, is emphasised in the EU Parliament’s report as vital for inclusive and legitimate SDG governance.
The Summary Of The Global Roadmap Includes:
- Institutional Strengthening: Establish or reinforce SDG coordination units with cross-ministerial mandates.
- Whole-of-Government Integration: Apply WoG frameworks to eliminate policy silos and increase operational coherence.
- Legislative Embedding of SDGs: Enshrine SDG targets in national laws and budgets (e.g., environmental provisions, SDG Units).
- Sustainable Financing: Leverage domestic tax reforms, MDB lending, and sustainability-linked financial instruments under strong governance protocols.
- Transparency & Monitoring: Invest in SDG 16, enhance anti-corruption data tools, and adopt global standards like TCFD and ISSB for reporting.
- Youth & Civil Society: Formalise youth councils, scale citizen data partnerships, and fund inclusive multi-stakeholder SDG initiatives.
- National–Global Alignment: Anchor local policies to high-level roadmaps like the Global Digital Compact to bridge digital divides and support SDGs.
- Monitoring & Review: Institutionalise VNRs and VLRs, ensure disaggregated data, and bolster statistical capacity—especially in developing contexts.
