Cholera is a highly contagious disease that occurs in settings without clean water and proper sanitation—from poor, remote villages to overcrowded cities, refugee camps and conflict zones. It causes profuse diarrhea and vomiting which can lead to death by intense dehydration, sometimes within hours. In recent years we responded to dozens of outbreaks, including massive epidemics in post-earthquake Haiti and war-torn Yemen.
What causes cholera?
Cholera is a bacterial infection that causes cells lining the intestine to produce large amounts of fluid. It spreads when someone ingests food or water contaminated with vomit or feces from a person carrying the disease. Contaminated food or water supplies can rapidly cause massive outbreaks.
What are the symptoms of cholera?
Cholera symptoms typically appear within 2-3 days of infection and vary widely, from mild to severe. In severe cases, people have profuse watery diarrhea, vomiting and leg cramps, leading to dehydration and shock that can quickly become fatal.
How can cholera be prevented and controlled?
Drinking and using safe water, using clean latrines or toilets, washing hands with soap, and ensuring good food hygiene are all ways to avoid the disease--but are often difficult or impossible for individuals in settings where cholera occurs. Prevention and control require measures at the community level, especially in making communally-supplied water safe for drinking.
Oral vaccines are another powerful tool that is being used more and more to help prevent cholera and to contain outbreaks at an early stage. But vaccination alone cannot end cholera: protection may not last beyond 3-5 years, and despite recent increases in production, the current global vaccine supply still falls far short of what’s needed to meet today’s needs.
How is cholera diagnosed?
A definitive cholera diagnosis requires a laboratory test. In field settings without access to lab facilities, rapid diagnostic tests can be used but are less reliable. Declaring an outbreak therefore requires laboratory confirmation. During outbreaks diagnosis is typically made without these tests, by taking a patient history and conducting a clinical examination.
How is cholera treated?
Mild and moderate cases of cholera are treated by having patients drink large amounts of oral rehydration solution—a mixture of sugars and salts in water. The sickest patients may need intravenous fluids and antibiotics. Without treatment, patients may die within hours.
How MSF responds to cholera
We started responding to cholera epidemics in Africa in the 1980s, and over time have found many ways to improve our effectiveness—from bringing care closer to communities, to implementing large-scale vaccination campaigns with oral cholera vaccines.
In 2017 we responded to several massive cholera outbreaks and many smaller ones. Yemen, where health care systems have collapsed amid ongoing full-scale war, experienced the largest epidemic since modern record-keeping began in 1949, with over 1.1 million cases reported. At the outbreak’s peak in June 2017, MSF facilities were treating over 11,000 patients per week and providing support to Yemen’s Ministry of Public Health and Population, via donations and training for staff. An ongoing cholera outbreak in the Democratic Republic of Congo—the country’s biggest since 1994—caused a reported 55,000 infections and 1,190 deaths in 2017, with MSF teams treating almost half of all reported cases.
An effective response to cholera involves engaging on several different fronts at the same time—and as fast as possible—to treat sick patients and to stop transmission within communities. The key pillars of this strategy rely on MSF’s medical staff working alongside epidemiologists, water and sanitation experts, logistics managers and community health promoters.
A big part of MSF’s ability to respond quickly is our standardized, pre-positioned cholera treatment kits that come equipped with rehydration salts, antibiotics and IVs, along with buckets, boots, chlorine and plastic sheeting—in short, everything needed to hit the ground running after an outbreak is confirmed.
Once cholera is confirmed, MSF conducts an outbreak investigation, or supports others to do so. This involves mapping where patients are coming from so that responders can prioritize the most affected areas. Throughout the epidemic epidemiologists continue looking into new cases in other areas.
Treatment facilities for patient care
When an outbreak is reported, MSF sets up dedicated cholera treatment centers at central locations. These centers are specialized isolation wards for rapidly treating large numbers of patients while preventing disease spread beyond the facility—patients, caregivers and medical staff have controlled entrances, exits, and decontamination areas, where they are sprayed with chlorine. In some situations, patients with mild cases are treated at simpler facilities called oral rehydration points, set up within or close to affected communities. This is especially important in settings where sick patients otherwise face a long journey to reach treatment, since cholera can cause death very quickly.
Diagram: Cholera treatment center
Water and sanitation improvements
MSF water and sanitation staff work to ensure availability of sufficient latrines and adequate supplies of clean water from safe sources, at both the home and communal levels. This typically involves activities ranging from distributing soap, clean buckets and water disinfection tablets for home use, to providing bucket chlorination at water sources before water is carried home.
Community health promotion
During outbreaks, health promoters visit schools, churches, markets and homes to help people implement measures to protect themselves against cholera and know what to do if they develop diarrhea.
MSF is increasingly using vaccination to help curb cholera outbreaks that are predicted to start soon or have just begun. A big advantage of the cholera vaccine is that it is oral, so it’s very simple to administer—people simply drink it. In one recent example, over half a million people were vaccinated in just two weeks in Lusaka, the densely populated capital of Zambia, using a new one-dose strategy (see below). But globally there is a shortage of vaccines available, so vaccination cannot be used nearly as widely as it should be.
Findings way to optimize strategies for using cholera vaccines is an important part of our response. For example, we recently showed that, although the vaccine is usually given in two doses that confer 3-5 year protection, one dose still curbs transmission effectively in the short term. This new strategy doubles the number of people who can be immunized during large outbreaks and helps stretch limited vaccine supply. We are also assessing simpler two-dose vaccination campaign strategies for use when enough vaccine is available, based on recent findings that the cholera vaccine remains effective for at least four weeks without refrigeration.
Our advocacy work focuses on the urgent need to expand global supplies of vaccine and to develop and confirm the effectiveness of simpler strategies for conducting mass vaccination campaigns. We participated in establishing the Global OCV Stockpile, maintained by the World Health Organization and supported by Gavi, the Vaccine Alliance, and that helps provide cholera vaccine for emergency use in outbreaks. As vaccine supplies gradually increase, we will continue advocating for more widespread use, including in routine vaccination rather than just to stop outbreaks once they’ve begun.