Cholera

Unique identifier / Notation

BI0204

Synonyms

Dysentery Asiatic cholera Epidemic cholera

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. Cholera is a global threat to public health (WHO, 2024a).

Primary reference(s)

WHO, 2024a. Cholera. World Health Organization (WHO). Accessed 24 May 2025.

Annotations

Additional scientific description

During the 19th century, cholera spread across the world from its original reservoir in the Ganges delta in India. Six subsequent pandemics killed millions of people across all continents. The current (seventh) pandemic started in South Asia in 1961 and reached Africa in 1971 and the Americas in 1991. Cholera is now endemic in many countries (WHO, 2024a).

There are many serogroups of V. cholerae, but only two - O1 and O139 - cause outbreaks. V. cholerae O1 has caused all recent outbreaks. V. cholerae O139 - first identified in Bangladesh in 1992 - has caused outbreaks in the past but recently has only been identified in sporadic cases. It has never been identified outside Asia. There is no difference in the illness caused by the two serogroups. These are extremely virulent, and it usually takes between twelve hours and five days for symptoms to develop following infection (WHO, 2024a).

The disease can affect both adults and children. Most of those infected with Vibrio cholerae do not develop any symptoms, although the bacteria are present in their faeces for one to ten days after infection, and are shed back into the environment, potentially affecting other people. Among people who develop symptoms, the majority have mild or moderate symptoms, while a minority develop acute watery diarrhoea which can lead to death if untreated. Treatment should be rapid, with intravenous fluids and antibiotics (WHO, 2024a).

Cholera diagnosis is confirmed by identifying Vibrio cholerae in the stools of affected individuals. Detection can be facilitated by the use of rapid diagnostic tests (RDTs) where one, or more, positive sample(s) triggers a cholera alert, but confirmation requires laboratory testing by culture, seroagglutination or polymerase chain reaction (PCR) (WHO, 2024a).

Cholera can be endemic or epidemic. A cholera-endemic area is an area where confirmed cholera cases were detected during the last three years with evidence of local transmission (meaning the cases are not imported from elsewhere). (WHO, 2024a). A cholera outbreak/epidemic can occur in both endemic countries and in countries where cholera does not regularly occur.

In cholera endemic countries an outbreak can be seasonal or sporadic and represents a greater than expected number of cases. In a country where cholera does not regularly occur, an outbreak is defined by the occurrence of at least one confirmed case of cholera with evidence of local transmission in an area where there is not usually cholera (WHO, 2024a).

The number of cholera cases reported to the World Health Organization (WHO) has continued to be high over the last few years. During 2023, 535 321 cases and 4007 deaths were reported to WHO from 45 countries, territories and areas, an increase from 44 in 2022 and 35 in 2021(WHO, 2024b). The discrepancy between these figures and the estimated burden of the disease is because many cases are not recorded due to limitations in surveillance systems and fear of impact on trade and tourism (WHO, 2024b).

Metrics and numeric limits

Researchers have estimated that every year, there are roughly 1.2 to 4.0 million cases, and 21,000 to 143,000 deaths worldwide due to cholera (WHO, 2019). Cholera can be endemic or epidemic. A cholera-endemic area is an area where confirmed cholera cases were detected during the last three years, with evidence of local transmission (WHO, 2024a).

The WHO has published guidance for Controlled Temperature Chain (CTC), case definitions and surveillance (GTFCC, 2024; WHO, 2024c; no date a).

Key relevant UN convention / multilateral treaty

International Health Regulations (2005), 3rd ed. (WHO, 2016).

Drivers

Cholera remains a global threat to public health and an indicator of inequity and lack of social development. The provision of safe water and sanitation is critical for the prevention and control of cholera (WHO, 2019).

Cholera transmission is closely linked to inadequate access to clean water and sanitation facilities. Typical at-risk areas include peri-urban slums, as well as camps for internally displaced persons or refugees. The consequences of a humanitarian crisis - such as disruption of water and sanitation systems, or the displacement of populations to inadequate and overcrowded camps - can increase the risk of cholera transmission, should the bacteria be present or introduced. Uninfected dead bodies have never been reported as the source of the epidemic (WHO, 2024a).

Cholera outbreaks occur regularly in some countries. In others, they are less frequent, and it may be years between outbreaks. Cholera is linked to limited access to safe water, basic sanitation facilities and poor hygiene practices. This may be due to conflict, population displacement, climate events like cyclones, floods, earthquakes or drought, and lack of investment in maintaining and improving WASH services and infrastructure (WHO, 2024a). These factors exacerbate the spread of cholera and make it harder to control. Disease surveillance and early warning systems, coupled with effective prevention and response capabilities, can reduce current and future vulnerability to infectious diseases following flooding (Brown and Murray, 2013).

Impacts

Cholera is a severe diarrheal disease that can be fatal within hours if not treated. Quick access to treatment is crucial. Researchers estimate that there are 1.3 to 4.0 million cases and 21 000 to 143 000 deaths from cholera worldwide each year (WHO, 2024a).

Multi-hazard context

Disaster-affected people eating food from centralized kitchens that are not properly equipped, or run are extremely vulnerable to outbreaks of foodborne disease. The combination of environmental contamination and improper handling of food increases the risk of epidemics of diseases such as cholera. Cholera can spread very quickly in overcrowded living areas such as refugee camps (WHO, 2002).

Risk Management

A multifaceted approach is key to control cholera, and to reduce deaths (WHO, 2024a). A combination of surveillance, water, sanitation and hygiene, social mobilisation, treatment, and oral cholera vaccines are used.

Water and sanitation interventions. The long-term solution for cholera control lies in economic development and universal access to safe drinking water and adequate sanitation. Actions targeting environmental conditions include the implementation of adapted long-term sustainable WASH solutions to ensure the use of safe water, basic sanitation and good hygiene practices in cholera hotspots (WHO, 2024a). In addition to cholera, such interventions prevent a wide range of other water-borne illnesses, as well as contribute to achieving Sustainable Development Goals related to poverty, malnutrition, and education. The WASH solutions for cholera are aligned with those of the Sustainable Development Goals (SDG 6) (WHO, 2024a).

Treatment: Cholera is an easily treatable disease. The majority of people can be treated successfully through prompt administration of oral rehydration solution. Severely, dehydrated patients are at risk of shock and require the rapid administration of intravenous fluids. These patients are also given appropriate antibiotics to diminish the duration of diarrhoea, reduce the volume of rehydration fluids needed, and shorten the amount and duration of V. cholerae excretion in their stool. Rapid access to treatment is essential during a cholera outbreak. Oral rehydration should be available in communities, in addition to larger treatment centres that can provide intravenous fluids and 24-hour care. With early and proper treatment, the case fatality rate should remain below 1% (WHO, 2024a).

Hygiene promotion and social mobilisation. Health education campaigns, adapted to local culture and beliefs, should promote the adoption of appropriate hygiene practices such as handwashing with soap, safe preparation and storage of food and safe disposal of the faeces of children. Funeral practices for individuals who die from cholera must be adapted to prevent infection among attendees. Further, awareness campaigns should be organised during outbreaks, and information should be provided to the community about the potential risks and symptoms of cholera, precautions to take to avoid cholera, when and where to report cases and to seek immediate treatment when symptoms appear. The location of appropriate treatment sites should also be shared. Community engagement is key to long-term changes in behaviour and to the control of cholera (WHO, 2024a).

Oral cholera vaccines. Currently, there are three WHO pre-qualified oral cholera vaccines: Dukoral®, Shanchol™, and Euvichol-Plus®. All three vaccines require two doses for full protection. More than 30 million doses of oral cholera vaccines have been used in mass vaccination campaigns. The campaigns have been implemented in areas experiencing an outbreak, in areas at heightened vulnerability during humanitarian crises, and among populations living in highly endemic areas, known as ‘hotspots’ always in conjunction with other cholera prevention and control strategies; vaccination should not disrupt the provision of other high priority health interventions to control or prevent cholera outbreaks; (WHO, 2014a; no date c).

The Global Task Force on Cholera Control (GTFCC), with its Secretariat based at WHO, was revitalized in 2014. The GTFCC is a network of more than 50 partners active in cholera control globally, including academic institutions, non-governmental organizations and United Nations agencies. To strengthen GTFCC support to countries, in 2020 a Country Support Platform (CSP) was established. The CSP, hosted by the International Federation of Red Cross and Red Crescent Societies (IFRC) provides multisectoral operational support as well as advocacy, coordination and policy guidance necessary for countries to develop, fund, implement and monitor their National Cholera Plans (NCPs) effectively in alignment with the Global Roadmap. In October 2017, GTFCC partners launched a strategy for cholera control Ending cholera: a global roadmap to 2030. The country-led strategy aims to reduce cholera deaths by 90% and to eliminate cholera in as many as 20 countries by 2030 (WHO, 2024a).

Monitoring

Cholera surveillance should be part of an integrated disease surveillance system that includes feedback at the local level and information-sharing at the global level. Cholera cases are detected based on clinical suspicion in patients who present with severe acute watery diarrhoea. The suspicion is then confirmed by identifying V. cholerae in stool samples from affected patients. Detection can be facilitated using rapid diagnostic tests where one, or more, positive sample(s) triggers a cholera alert. The samples are sent to a laboratory for confirmation by culture or PCR. Local capacity to detect (diagnose) and monitor (collect, compile, and analyse data) cholera occurrence, is central to an effective surveillance system and to planning control measures. Countries affected by cholera are encouraged to strengthen disease surveillance and national preparedness to rapidly detect and respond to outbreaks. Under the International Health Regulations, notification of all cases of cholera is no longer mandatory (WHO, 2024). However, public health events involving cholera must always be assessed against the criteria provided in the regulations to determine whether there is a need for official notification (WHO, 2014; 2024a).

WHO supports countries to conduct all-hazards strategic risk assessment in the contexts of health emergencies and disasters, which results in the development of a country's risk profile. Empowered with the country risk profile, inclusive of a seasonal risk calendar, countries can anticipate potential emergencies before they occur to trigger early alerts and inform early actions (WHO, 2021).

WHO's Early Warning, Alert and Response System (EWARS) has been designed to improve disease outbreak detection in emergency settings, such as in countries in conflict or following a natural disaster. It is a simple and cost-effective way to rapidly set up a disease surveillance system. EWARS is deployed during an emergency as an adjunct to the national disease surveillance system. WHO works with Ministries of Health and health sector partners to train local health workers to use the system. After the emergency, EWARS should re-integrate back into the national system (WHO, no date b).