Cholera

Cholera remains a global threat, especially in the developing world wherever access to safe drinking water and adequate sanitation cannot be guaranteed, including slums and refugee camps. The disease is one of the key indicators of social development. It affects the world’s poorest populations and aggravates poverty.

Facts & Figures

>172,000 cholera deaths

in 2015

41% of reported cases

in Africa

37% of reported cases

in Asia

80% of cases

can be treated with oral rehydration salts

3 oral vaccines

help prevent cholera

Epidemiology

The global annual burden of cholera

is estimated to be around 1.3 to 4.0 million cases, with 21,000 to 143,000 deaths. However, many cases are not recorded due to limitations in surveillance systems and fear of impact on trade and tourism. Despite current national and international efforts, cholera is still a neglected and under-reported disease.

Pathogen & Transmission

Cholera is an acute intestinal infection

caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. It has a short incubation period and produces an enterotoxin that causes copious, painless, watery diarrhea that can quickly lead to severe dehydration and death if treatment is not given promptly. Cholera affects both children and adults. Most people infected with V. cholerae do not become ill, although the bacterium is present in their feces for 1-10 days after infection and can potentially infect other people. Among people who develop symptoms, the majority have mild or moderate symptoms, while a minority develop acute watery diarrhea with severe dehydration, which can lead to death if left untreated.

Treatment

Cholera is an easily treatable disease

With early and proper treatment, the case fatality rate should remain below 1%. Most people can be treated successfully with oral rehydration solution (ORS). The WHO/UNICEF ORS standard sachet is dissolved in 1 liter of clean water. Adult patients may require up to 6 liters of ORS to treat moderate dehydration on the first day. Severe cases will need rapid treatment with intravenous fluids and antibiotics, but mass administration of antibiotics is not recommended, as it has no proven effect on the spread of cholera and contributes to increasing antimicrobial resistance.

Endemic disease & epidemic disease

Cholera is both an endemic and an epidemic disease

Today it is endemic in many countries. A cholera-endemic area is an area where confirmed cholera cases were detected during 3 out of the last 5 years with evidence of local transmission (meaning the cases are not imported from elsewhere). Epidemic cholera (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. Almost every developing country faces cholera outbreaks or the threat of a cholera epidemic.

Control & Prevention

Cholera can be controlled by taking a multifaceted approach that combines epidemiologic surveillance, water sanitation and hygiene, treatment, and oral cholera vaccines as well as information, training and education of healthcare professionals and communities.

Water Sanitation

To combat this highly infectious water-borne disease, water sanitation measures are essential: a clean water supply, systems for safe sewage disposal (including latrines), other sanitation infrastructures, awareness and adoption of hygienic practices. Even if improved water and sanitation are the mainstay of prevention and sustained control of cholera, those goals need time and long-term investment to be achieved, especially in impoverished countries where enteric diseases are endemic.

Oral cholera vaccines

Oral cholera vaccines (OCVs) should be used in conjunction with water and sanitation improvements to control cholera outbreaks and for prevention in areas known to be high risk for cholera. Currently there are 3 WHO pre-qualified OCVs: Dukoral®, Shanchol™, and Euvichol®. All 3 vaccines require 2 doses for full protection. In 2013, WHO established a stockpile of 2 million doses for use in outbreak control and emergencies. OCVs are used in non-emergency settings, as part of a longer-term cholera control plan along with other strategies for cholera control. To date, more than 5 million doses of OCVs have been used in mass vaccination campaigns with WHO support. The campaigns have been implemented in areas experiencing an outbreak, areas that are especially vulnerable during humanitarian crises, and among populations living in highly endemic areas.

Cholera in Africa

Cholera remains a significant cause of illness and death in many African countries, and sub-Saharan Africa bears the brunt of global cholera. According to the Pasteur Institute, it is in Africa that the situation is the most alarming. In 2009, Africa accounted for 98% of the total cholera cases reported to WHO. Access to safe water and sanitation is still inadequate in many countries in Africa.

“Fighting cholera effectively is a voluntary decision, based on targeted approaches suitable to local needs. It involves requisite social mobilization and is prepared and implemented with local authorities and field actors, with support from governmental and international authorities.”
Findings of the 4th IDEA Africa meeting in Cotonou, Benin, Oct. 5-9, 2015

Cholera in Asia

The Southeast Asia region, which includes Bangladesh and India, has the largest populations at risk for cholera. Reported cases in Asia increased nearly threefold from 2010 to 2011 and included an increased number of deaths. Many countries in the region face known risk factors for cholera outbreaks such as poverty, lack of development, and high population density. Additionally, the region is susceptible to extreme weather and frequent and widespread flooding, which can contaminate water sources and dislocate populations.

In large parts of Asia, hundreds of thousands of cholera cases are not recorded owing to serious limitations in surveillance systems.

IDEA Asia uses an integrated multisectorial strategy in the fight against cholera. It focuses on 6 areas for action and 6 policy goals:

  1. Develop national cholera action plans and implement road maps in cholera-prone countries.
  2. Engage decision makers and healthcare professionals to recognize cholera as a public health problem that can be prevented, controlled and ultimately eliminated.
  3. Ensure the provision of safe water, sanitation and hygiene along the lines of the Millennium Development Goal 7.
  4. Establish an efficient cholera surveillance system.
  5. Advocate the recommendation, use, availability and access of cholera vaccination in a coordinated approach with other interventions.
  6. Improve knowledge and attitudes about cholera among the public.

Each policy goal describes the current state of affairs, actions and strategies. For more information, see: Cholera Prevention, Control and Elimination: A policy brief by the Initiative against Diarrheal and Enteric Diseases in Asia.

Source: CDC Cholera in Southeast Asia