Cholera is an intestinal bacterial infection that spreads through contaminated water. It can cause severe diarrhea and dehydration.
Modern sewage and water treatment technologies have essentially eliminated cholera in most industrialized countries. The condition still exists in Africa, Southeast Asia, and in parts of the Caribbean, particularly Haiti.
As evidenced by the 2010 cholera outbreak in Haiti, in the immediate aftermath of the devastating earthquake there, the risk of a cholera outbreak is highest when poverty, war, or natural disasters leave people living in crowded conditions, without access to clean water and proper sanitation.
It’s not just the residents of these areas who are affected during an outbreak. Visitors can be at risk for catching the disease as well, the Centers for Disease Control and Prevention (CDC) warns.
Although most cases aren't severe and can be treated, the condition can lead to death for those who don't get the proper care.
Causes and Risk Factors of Cholera
Cholera is caused by a bacterial infection. There are two serotypes, or strains, of Vibrio cholerae that cause outbreaks of cholera: O1 and O139. Of the two, O1 is more common.
If you’ve been exposed to these bacteria, O1 and O139 release the cholera toxin into your bloodstream. This in turn causes the cells that line your intestine to release increased amounts of water, which can lead to dehydration.
Drinking contaminated water or consuming contaminated food is the most common way you can be exposed to the O1 or O139 bacteria.
O1 and O139 bacteria are most common in places with poor water treatment, sanitation, and hygiene practices, according to the CDC. In addition, although there are no other animals besides humans in which the bacteria can reproduce and spread, Vibrio cholerae frequently attach to the shells of crabs, shrimps, and other shellfish. As a result, raw and undercooked shellfish have been sources of cholera infections in the United States.
Raw fruits and vegetables are also a common source of cholera in areas where the disease is found, because crops may be treated with contaminated water or manure fertilizers. Similarly, in regions where cholera is common, grains such as rice that are contaminated after cooking and kept at room temperature for several hours can also contain cholera bacteria.
Everyone is at risk for cholera (though infants can get immunity from a nursing mother who has previously had the infection).
Research suggests the following may increase your risk:
- Poor sanitary conditions
- Reduced stomach acid
- Type O blood
- Household exposure
In general, cholera is common in areas where a safe supply of drinking water is difficult to maintain, including refugee camps, impoverished countries, and areas impacted by famine, war, or natural disasters.
Although the bacteria that causes the infection doesn’t survive in stomach acid, those with low levels of stomach acid, including children, older adults, and people who take antacids, H2 blockers, or proton pump inhibitors are a greater risk. In addition, research indicates that people with type O blood are twice as likely to develop cholera compared with people with other blood types — though it's unclear why.
Cholera also spreads easily. A person infected with the bacteria can cause a one-million-fold increase in Vibrio cholerae numbers in the environment through a single diarrheal episode, according to the National Institute of Allergy and Infectious Diseases.In addition, because people with cholera shed bacteria in their stool for 7 to 14 days, they can infect anyone who comes in contact with their feces, or water contaminated by it.As a result, you’re at increased risk for infection if you live with someone who has cholera.
Duration of Cholera
As noted above, symptoms usually appear within two or three days of exposure to the bacteria. In mild or uncomplicated cases of cholera, symptoms subside on their own within three to six days of onset and the bacteria disappear from your system within two weeks.In very severe cases of dehydration, patients will need intravenous fluid replacement.
Prevention of Cholera
Cholera isn't endemic to the United States (per the WHO, a cholera-endemic area means that confirmed cholera cases were detected there during the last three years with evidence that transmission was local).Nearly all cases of cholera in the United States are acquired when people travel internationally.
You can avoid getting the illness when traveling abroad with the following measures:
- Drink only beverages that are bottled, canned, boiled, or chemically treated, and avoid tap water, fountain drinks, and ice cubes.
- Wash your hands often with soap and (clean) water, or use a hand cleanser with at least 60 percent alcohol — especially before eating or preparing food and after using the bathroom.
- Eat prepackaged food or food that's freshly cooked and served hot.
- Don't eat raw or uncooked shellfish, including sushi.
- Avoid dairy foods.
- Use bottled, boiled, or chemically treated water to brush your teeth, prepare food, wash dishes, and make ice.
In addition, the U.S. Food and Drug Administration (FDA) has approved a single-dose live oral cholera vaccine called Vaxchora for adults ages 18 to 64 who are traveling to an area of active cholera transmission. The vaccine is designed to protect against cholera caused by O1 strains of Vibrio cholerae.
If you’re planning on traveling to areas with active cholera transmission, talk to your doctor about this vaccine.
Three other anti-cholera vaccines — Dukoral, ShanChol, and Euvichol-Plus — have been approved by the WHO to supply the United Nations but they aren’t available in the United States.
No cholera vaccine is 100 percent protective, though, and vaccination against cholera isn’t a substitute for standard prevention and control measures.
Research and Statistics: Who Gets Cholera?
The WHO estimates that between 1.3 million and 4 million cholera cases occur globally each year, and 143,000 people die from the disease annually.
The risk of cholera or severe symptoms from infection doesn’t differ among racial or ethnic groups. But cholera is likely to be endemic in certain countries in Africa, the eastern Mediterranean region, southeast Asia, and the western Pacific, according to the WHO.
Resources We Love
World Health Organization (WHO)
Within the United Nations system, the WHO is the authority on international health. Their website provides a comprehensive look at cholera — what it is, how it spreads, and how to prevent it — as well as news on cholera outbreaks and vaccinations.
Centers for Disease Control and Prevention (CDC)
In addition to covering all the basics of cholera, the CDC provides the latest statistics and data on the disease, insight into their own efforts to investigate and combat outbreaks, and helpful information for travelers.
Mayo Clinic
A highly trusted source for Everyday Health editors, the Mayo Clinic offers clear, straightforward info on cholera and its potential complications and what to do if you believe you've been exposed to it.
Additional reporting by Brian P. Dunleavy.
Editorial Sources and Fact-Checking
- Cholera. Mayo Clinic. February 1, 2020.
- General Information: Cholera. Centers for Disease Control and Prevention (CDC). August 5, 2020.
- Cholera. World Health Organization. January 17, 2019.
- Cholera. National Institute of Allergy and Infectious Diseases. May 12, 2016.
- Fanous M, King KC. Cholera. StatPearls. June 6, 2020.
- Cholera. National Organization of Rare Disorders. 2009.
- Technical Note: Use of Antibiotics for the Treatment and Control of Cholera. World Health Organization. May 2018.
- Komiazyk M, Palczewska M, et al. Neutralization of Cholera Toxin by Rosaceae Family Plant Extracts. BMC Complementary and Alternative Medicine. June 20, 2019.
- Travelers' Diarrhea. CDC. October 8, 2019.
- Dehydration. MedlinePlus. April 15, 2016.
