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Public Health

Vetted resources and information on current public health events.

What is Cholera

Cholera is an extremely virulent disease with severe acute diarrhea caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. It takes between 12 hours and 5 days for a person to show symptoms after ingesting contaminated food or water. Cholera affects both children and adults and can kill within hours if untreated. Most people infected with V. cholerae do not develop any symptoms, although the bacteria are present in their faeces for 1-10 days after infection and are shed back into the environment, potentially infecting other people. Among people who develop symptoms, the majority have mild or moderate symptoms, while a minority develop acute watery diarrhea with severe dehydration. This can lead to death if left untreated.

Cholera remains a global threat to public health and an indicator of inequity and lack of social development. Cholera can be endemic or epidemic.

A cholera-endemic area is an area where confirmed cholera cases were detected during the last 3 years with evidence of local transmission (meaning the cases are not imported from elsewhere). 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 1 confirmed case of cholera with evidence of local transmission in an area where there is not usually cholera.

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

Cholera is now endemic in many countries. The number of cholera cases reported to WHO has continued to be high over the last few years. During 2020, the WHO was notified of 323,369 cases and 857 deaths from 24 countries.

A multifaceted approach is key to control cholera, and to reduce deaths. A combination of surveillance, water, sanitation and hygiene, social mobilization, treatment, and oral cholera vaccines are used.

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 use of safe water, basic sanitation and good hygiene practices in cholera hotspots.  In addition to cholera, such interventions prevent a wide range of other water-borne illnesses, as well as contributing to achieving goals related to poverty, malnutrition, and education.  The WASH solutions for cholera are aligned with those of the Sustainable Development Goals (SDG 6).

After decades of progress against cholera, cases are again on the rise, even in countries that had not seen the disease in years. 

Cholera is an acute intestinal infection that spreads through food and water contaminated with the bacterium Vibrio cholerae, often from faeces. With safe water and sanitation, cholera can be prevented. It can kill within hours when not treated, but immediate access to treatment saves lives.

While the triggers for cholera outbreaks—like poverty and conflict—are enduring, climate change and conflict are now compounding the problem. Extreme climate events like floods, cyclones and droughts reduce access to clean water and create an ideal environment for cholera to thrive.

In 2022, 44 countries reported cholera cases, a 25% increase from the 35 countries that reported cases in 2021. This trend continues into 2023. The recent outbreaks have also been more deadly, with case fatality rates being the highest recorded in over a decade. 

This increase in outbreaks and cases is stretching the global capacity to respond. There is a shortage of cholera tools, including vaccines. 

WHO considers the current global risk from cholera as very high and is responding with urgency to reduce deaths and contain outbreaks in countries around the world.   

Cholera Health Emergency | WHO

Current Outbreaks

Table 1: Cholera cases and deaths reported to WHO from WHO regions, as of 15 December 2023*

* Case and death numbers presented are not directly comparable due to differences in case definitions, reporting systems, and general underreporting. All data are subject to verification and change due to data availability and accessibility. Respective figures and numbers will be updated as more information becomes available. The data in Table 1 includes suspected, rapid diagnostic test (RDT) positive, and culture-confirmed cholera cases. No cholera cases of local transmission have been reported in the European Region.

** Afghanistan reports AWD through the sentinel site surveillance system.

*** Refers to the laboratory-confirmed cases only.

WHO Disease Outbreak News Updates

Multi-country outbreak of cholera, External situation report #4
WHO Emergency Situational Update | 11 January 2024
Data as of December 15, 2023
 
WHO Global Risk
Global Risk Coutnries/Territories
Very High 30
Highlights

Since the publication of the last situation report on the multi-country outbreak of cholera on 7 December 2023 (which included data up to 15 November), and as of 15 December 2023, one new country (Togo) has reported an outbreak of cholera or acute watery diarrhoea (AWD). In total, at least 30 countries have reported cases since 1 January 2023. 

Preliminary data from Member States indicate that the number of cholera cases reported in 2023 as of 15 December has surpassed that of 2022, with over 667 000 cases and 4000 deaths. These figures must be interpreted with caution given the varying surveillance systems and capacity across countries, which means that 2023 data are not directly comparable to reports from previous years.

Nearly a year has passed since WHO classified the global resurgence of cholera as a grade 3 emergency, the highest internal level for a health emergency requiring a comprehensive response at the three levels of the organization. WHO is currently reviewing its response to cholera globally to identify key lessons and make evidence-based adjustments where needed to better coordinate activities in the coming months.

The WHO African Region remains the most affected region with 17 countries reporting cholera cases throughout 2023.

  • In the south-east and central Africa subregions, the Democratic Republic of the Congo (DRC) continues to report close to 1000 cases each week. Zimbabwe is experiencing a rise in cases, particularly in the provinces of Harare, Manicaland, and Masvingo. Additionally, Mozambique is reporting new cases and further geographical spread. Burundi and Zambia also continue to report active cholera outbreaks.

  • In the Greater Horn of Africa, concerning increases in new cases have been observed in Sudan, where nearly 1000 new cases are reported weekly across expanding geographical areas, exacerbating the already dire humanitarian crisis. Ethiopia also faces challenges in controlling ongoing outbreaks in eight regions, with approximately 400 new cases reported each week.
 
WHO Risk Assessment

The overall capacity to respond to the multiple and simultaneous outbreaks continues to be strained due to the global lack of resources, including shortages of the oral cholera vaccine, as well as overstretched public health and medical personnel, who are dealing with multiple disease outbreaks and other health emergencies at the same time.

Based on the increasing number of outbreaks and their geographic expansion, as well as a lack of vaccines and other resources, WHO continues to assess the risk at global level as very high.