What is Cholera?

Cholera 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 endemic.  Cholera is commonly found in countries where there is a lack of clean water, inadequate sanitation, poor hygiene and overcrowding.


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. Travellers 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.


How is Cholera diagnosed?

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 vomit 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 travelling 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.
  • Wash hands, with soap and water for at least 15 seconds, 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 (travellers 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 vomit with heat, bleach or other disinfectants.
  • Remember these simple rules:  Boil it, cook it, peel it or forget it.


This page 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.

Source:  Ontario Ministry of Health and Long-Term Care, Public Health Division.


For Further Information

Call the Infectious Disease Program: (807) 625-5900

or toll-free 1-888-294-6630

Health Topic
Diseases & Infections