Cholera

What Is Cholera? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Joseph Bennington-Castro
By Medically Reviewed by 
Reviewed:
Medically Reviewed

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 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.

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.

Signs and Symptoms of Cholera

Cholera is caused by the bacteria Vibrio cholerae. Most people infected don’t develop any symptoms, and among the majority of those who do, the symptoms are mild to moderate.

Roughly 1 in 10 people sickened with cholera will develop severe symptoms. In those who experience these symptoms, death can occur within a few hours if they don’t receive effective treatment.

Vibrio cholerae takes between 12 hours and five days to incubate in the body before causing symptoms.

Most of the time, symptoms appear within two to three days of exposure to the bacteria.

Symptoms of cholera infection include:

  • Diarrhea
  • Nausea and vomiting
  • Sleepiness or lethargy
  • Dehydration
  • Muscle cramps
  • Rapid pulse
  • Electrolyte imbalance
  • Excessive thirst and low urine output
  • Dry skin, dry mucous membranes (such as inside the nose or eyelids), and dry mouth
Diarrhea caused by cholera typically starts suddenly and can quickly cause dangerous levels of dehydration. Cholera-related diarrhea can be hard to differentiate from diarrhea caused by other illnesses, but with cholera, your diarrhea may have a pale, milky appearance.

Nausea and vomiting are common in the early stages of cholera and can last for hours.

Severe diarrhea and vomiting caused by cholera can lead to dehydration, usually within hours of when symptoms first appear. In severe cases, dehydration from cholera can lead to a loss of body weight of 10 percent or more.

Those who experience cholera dehydration typically have symptoms such as irritability, fatigue, sunken eyes, dry mouth, extreme thirst, and dry and shriveled skin, as well as lack of urination, reduced blood pressure, and irregular heartbeat.

In addition, cholera-related dehydration can cause an electrolyte imbalance, or a rapid loss of vital minerals in your blood. People with an electrolyte imbalance may experience abnormal heart rhythms or muscle cramps due to reduced levels of sodium, chloride, and potassium in the blood, along with hypovolemic shock caused by dangerous drops in blood pressure and oxygen flow.

If untreated, shock accompanied by an electrolyte imbalance can lead to death.

Other complications can include low blood sugar and kidney failure. (See Complications, below).

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. 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 common sources 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 don’t survive in stomach acid, people 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.

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.

How Is Cholera Diagnosed

In areas where the infection is common, cholera may be recognized by its symptoms, but the only way to confirm the diagnosis of cholera is to identify the O1 or O139 bacteria in a stool sample.

An early diagnosis can lead to faster treatment and isolation of infected individuals, which can help control outbreaks.

Prognosis of Cholera

Risk of death is higher in children, pregnant women, and the elderly.

Generally, the risk for death from cholera has declined globally in recent years because of enhanced access to healthcare, and improved sanitation and education. With effective rehydration, less than 1 percent of those infected with cholera die from it.

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.

Treatment and Medication Options for Cholera

Treatment for the infection focuses on restoring fluids and salts lost through diarrhea (or vomiting).

The fluid replacement typically recommended is a WHO-developed rehydration solution called oral rehydration salts (ORS). ORS is available as a powder that can be combined with boiled or bottled water. As long as it’s mixed with clean water, it’s designed to be consumed in large amounts in order to provide full rehydration.

Up to 80 percent of cases can be successfully treated with ORS.

In the most severe instance of cholera, treatment may require intravenous (IV) fluid replacement.

Medication Options for Cholera

In some cases, your doctor may recommend the use of prescription antibiotics — usually tetracycline (Sumycin) or doxycycline (Vibramycin) — to help reduce the severity of symptoms and speed up the recovery time.

In addition, zinc supplements may help decrease the duration of diarrhea in children under 5 years old with cholera.

Alternative and Complementary Therapies

In general, research on the use of alternative and complementary therapies in cholera is limited. But a study published in 2019 suggests that extracts from the rose family of plants — traditionally used as a remedy for diarrhea in some parts of eastern Europe — may help slow the growth of the bacteria and inhibit the cholera toxin.

Plant-extract formulations may eventually be helpful in easing symptoms, in conjunction with established treatments, but it’s important to note that this approach shouldn’t be used in place of rehydration therapy or antibiotics.

Prevention of Cholera

Cholera isn’t endemic to the United States (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.
Three 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.

Complications of Cholera

Although most cases of cholera are mild — particularly if treated — the infection can be fatal.

Those with the most severe illness lose large amounts of fluids and electrolytes quickly, causing death within hours.

In less extreme situations, people who can’t get treated right away can die of dehydration and shock hours to days after their symptoms first appear.

Other complications of cholera include:

  • Low blood sugar (hypoglycemia)
  • Reduced potassium levels
  • Kidney failure
If cholera makes you too ill to eat, dangerously low levels of blood sugar can occur, causing seizures, loss of consciousness, and death. Children are at increased risk for this complication.

In addition, severe diarrhea causes people with cholera to lose large quantities of essential minerals the body needs, including potassium. Reduced potassium levels can interfere with heart and nerve function and be life-threatening.

Finally, shock caused by cholera can lead to kidney failure, in which the kidneys lose their filtering ability, allowing excess fluids, some electrolytes, and wastes to build up in the body. This is a potentially life-threatening condition.

Research and Statistics: Who Gets Cholera?

Approximately 1.3 million to 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.

Related Conditions of Cholera

The bacteria that cause cholera have, at least to date, not been linked to other health conditions. But cholera’s symptoms may mimic those of other conditions, including:

Traveler’s Diarrhea

Traveler’s diarrhea is the most common travel-related illness. Like cholera, it’s caused by bacteria. You’re at increased risk of exposure if you travel to places in Asia (excluding Japan and South Korea), the Middle East, Africa, and South and Central America.

Unlike cholera, traveler’s diarrhea is rarely life-threatening, but if nothing else, it can make for a very unpleasant trip.

Dehydration

Dehydration causes dry mouth, fatigue, dizziness, headache, and muscle cramps. You may also urinate less often than you normally do, or have dark urine.

Most cases of dehydration are mild and resolved by drinking lots of fluids (water or sports drinks). Severe dehydration, though, may require intravenous fluids administered by a health professional. Dehydration doesn’t cause diarrhea, but severe diarrhea and vomiting can lead to dehydration.

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

Show Less