What is cholera?

Cholera (kol-er-uh) is a diarrheal disease caused by eating or drinking food or water contaminated with the bacterium Vibrio cholerae.  

How common is cholera?

Cholera is not a common disease in Canada. In Ontario, an average of one case per year is reported and all cases have been exposed to cholera in a country where cholera is endemic1. Cholera is commonly found in countries where there is a lack of clean water, inadequate sanitation, poor hygiene and overcrowding. Worldwide, it affects three to five million people and causes 100,000 - 120,000 deaths yearly.

What are the symptoms of cholera?

Cholera infection may cause a variety of symptoms, including:

  • profuse but painless watery diarrhea (rice watery stools)
  • vomiting of clear fluid
  • nausea

Most people infected with Vibrio cholerae do not exhibit any symptoms, but they can still pass the disease to others. About 5% of infected people will experience severe symptoms. If not treated, an infected person can rapidly loose bodily fluids which can lead to severe dehydration, shock and death.

Symptoms of cholera may appear from 6 hours to 5 days after exposure, but usually appear within 2-3 days.

If you have signs and symptoms of illness, and you have had exposure to possible sources of the cholera bacterium, contact a physician.

How is cholera spread?

Vibrio cholerae bacteria are released with the bowel movements of infected individuals. People can shed Vibrio cholerae in their stool for several months; however, most individuals will stop shedding the bacteria 2-3 days after symptoms have resolved. Person-to-person transmission is extremely rare, even for healthcare workers during epidemics.

You can become infected by :

  • ingesting contaminated water
  • ingesting contaminated food such as raw or undercooked shellfish and fish, moist grains held at room temperature and raw or partially dried fish
  • unintentionally ingesting feces from an infected person

Who is at risk?

Individuals at higher risk for infection include humanitarian aid workers in countries experiencing cholera cases or an outbreak, especially after natural disasters. Travelers visiting endemic areas with limited access to safe food and water are also at higher risk. Individuals at higher risk should consider getting vaccinated prior to travel.

Is there a vaccine for cholera?

A number of safe and effective vaccines for cholera are available. Contact your local travel clinic. You may also check the Public Health Agency of Canada's Travel Health Notices before traveling to another country.

How is cholera diagnosed and treated?

When symptoms occur, a proper diagnosis is very important, as cholera has the potential to cause death from severe dehydration unless rehydration occurs. Therefore, if you think that you might have cholera, you should immediately start drinking oral rehydration solutions (including salt and minerals) and seek medical attention immediately. Cholera is normally diagnosed by detection of the bacteria in stool or vomitus and, in some cases, by the use of a blood test. Your physician can order the appropriate diagnostic tests and start an appropriate treatment.

How can I prevent cholera?

When traveling to places at risk for cholera, practice the following preventative measures :

  • Consult with a travel clinic regarding the  incidence of cholera and vaccination recommendations before travel. 
  • Thorough hand washing before preparing or consuming foods.
  • Make sure hands are properly washed with safe water after using the toilet, changing diapers, or after assisting others with the toilet.
  • Only drink water that you know is uncontaminated. If you are not sure, treat the water yourself (e.g. boil the water for at least five minutes). Chlorinate or boil water that will be used for drinking, cooking, washing dishes, washing hands and brushing teeth (Travelers can obtain products for disinfecting water from pharmacies).
  • Ensure ice is made from uncontaminated water.
  • Avoid eating raw oysters and undercooked shellfish and fish as well as foods from street vendors.
  • Disinfect linens and articles if soiled by feces or vomitus with heat, bleach or other disinfectants.
  • Remember these simple rules: Boil it, cook it, peel it or forget it.

What causes cholera outbreaks?

Cholera outbreaks usually occur as a result of shortages of clean (uncontaminated) water, inadequate sewage infrastructure and poor hygiene. In October of 2010, an outbreak of cholera was reported in Haiti as a result of an earthquake with over 60,000 confirmed cases, including nearly 1,500 deaths.


  1. Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iPHIS) database, extracted April 2010.
  2. Public Health Agency of Canada: Travel Health
  3. Centers for Disease Control and Prevention
  4. World Health Organization
  5. Pickering LK, et al. 2006. Red book: 2006 report of the Committee on Infectious Diseases. 27th ed. American Academy of Pediatrics, Elk Grove Village, IL.
  6. Heymann DL. 2008. Control of communicable diseases manual. 19th ed. American Public Health Association, Washington D.C.

This fact sheet provides basic information only. It must not take the place of medical advice, diagnosis or treatment. Always talk to a health care professional about any health concerns you have, and before you make any changes to your diet, lifestyle or treatment.

For More Information

Call ServiceOntario, Infoline at:
1-866-532-3161 (Toll-free in Ontario only)
TTY 1-800-387-5559.
In Toronto, TTY 416-327-4282
Hours of operation : 8:30am - 5:00pm

If you are a member of the media, call Communications and Marketing Branch at 416-314-6197 or visit our News Room section.