Cholera in Nigeria, 2026: 65,690 reported cases so far

1. The outbreak

65,690 cases of cholera have been reported in Nigeria in 2026, with counts running to 17 August 2026.

That is already more than the 23,885 reported in the whole of 2025 (2.8 times as many).

Case definition: suspected, rapid-test-positive and culture-confirmed cases, as compiled by WHO. Figures are as reported by the originating public-health authorities and compiled by ENCLAI; they are not modelled estimates.

2. The pathogen

Cholera is an acute bacterial intestinal infection caused by toxigenic Vibrio cholerae O-group 1 (O1) or O-group 139 (O139).¹ Only toxigenic strains of serogroups O1 and O139 have caused widespread epidemics and are reportable to the World Health Organization (WHO) as "cholera."¹ V. cholerae O1 has two biotypes, classical and El Tor, and each biotype can be divided into distinct serotypes: Inaba, Ogawa, and rarely, Hikojima.¹ Globally, cholera cases are caused by O1 El Tor organisms; classical appears to be extinct, although El Tor variants with characteristics of both classical and El Tor biotypes have emerged and are now commonplace.¹

Toxigenic V. cholerae O1 and O139 are free-living bacterial organisms found in fresh and brackish water, often in association with copepods or other zooplankton, shellfish, and aquatic plants.¹ Cholera bacteria also can live in brackish (slightly salty) and coastal waters.²

3. Pathogenesis and bacteriology

The pathogen typically remains in the gastrointestinal tract and does not invade the bloodstream.¹ Severe cholera (cholera gravis) occurs in approximately 10% of cholera episodes and is characterized by profuse watery diarrhea, described as rice-water stools, often accompanied by nausea and vomiting that can rapidly lead to severe volume depletion.¹ Additional symptoms, including muscle cramps, are secondary to the resulting electrolyte imbalances.¹ Untreated cholera can cause rapid loss of body fluids, which can lead to severe dehydration, hypovolemic shock, and death within hours.¹

4. Modes of transmission and reservoirs

Cholera infections are acquired most often from untreated drinking water in which toxigenic V. cholerae naturally occurs or has been introduced from the feces of an infected person.¹ Other common vehicles include raw or undercooked food, especially fish and shellfish.¹ Direct person-to-person transmission, including to healthcare professionals during epidemics, has been reported and may be an important transmission pathway in some settings.¹ Casual contact with someone with cholera is not likely to spread the infection.²

5. Clinical description and complications — why the disease matters

Symptoms appear 12 hours to 5 days after infection.³ Most people with the disease have mild or moderate symptoms.³ A minority of patients develop severe acute watery diarrhoea and life-threatening dehydration.³ Clinical findings include dry mucous membranes and loss of skin turgor, hypotension, tachycardia, and thirst.¹

The case-fatality ratio for untreated cholera can reach 50%, but with adequate and timely rehydration, the case-fatality ratio is <1%.¹ If untreated, severe dehydration can lead to kidney failure, shock, coma, and death.⁴ Untreated cholera, a severe diarrheal disease, can prove fatal within hours.³

6. Epidemiology: risk groups, geography and seasonality

Cholera is endemic to approximately 50 countries, primarily in South Asia, Southeast Asia, and Africa.¹ People living in areas with unsafe drinking water, poor sanitation, and inadequate hygiene are at highest risk of getting cholera.² People who have inadequate gastric acidity (e.g., elevated pH secondary to an acid-blocking medication) have a greater risk for infection, and they, along with those with blood type O, are at greater risk for developing severe disease if infected.¹ WHO received reports from 45 countries in 2023, detailing 535 321 cases and 4007 deaths.³

7. Significance as a public-health problem

Global cholera burden is estimated by researchers at 1.3 to 4.0 million cases and 21 000 to 143 000 deaths annually.³ A coalition of governmental and nongovernmental organizations, UN agencies and academic institutions, the Global Task Force on Cholera Control (GTFCC) shares a common mission to reduce the global cholera burden.³ In 2023, WHO assessed the global cholera risk as very high and declared a grade 3 (WHO's highest) emergency.¹

More

Cholera in Nigeria: live counts and trend · Cholera: all countries · Active outbreaks · How we verify