Cholera

Cholera is a disease caused by the bacterium Vibrio cholerae.

Symptoms

It is common for people to be infected with the bacterium that causes cholera and not realize it. In some benign cases, especially in children, the symptoms resemble that of gastroenteritis. Most often, the toxic infection (infection due to a bacteria secreting a toxin) is characterized by very abundant, watery stools, sometimes with blood, accompanied by vomiting, severe abdominal cramps, and extremely painful muscle cramps. In untreated cases, severe dehydration may be followed by circulatory collapse (blood pressure drop) - with a fatality rate of 50 percent. However, when cholera is treated with an appropriate antibiotic and fluid therapy, mortality is 1 to 5 percent.

Transmission

Cholera is usually spread by the ingestion of contaminated water or food, especially raw or undercooked shellfish and fish. It is rarely transmitted from person to person. The incubation period varies from a few hours to 3 days (maximum of 7 days). Gastric achlorhydria (marked by the absence of hydrochloric acid and the inability to digest food properly. Can follow the use of certain drugs to treat ulcers) increases a person's vulnerability to the disease. Infected individuals usually become contagious 2 to 3 days before the disease becomes manifest and remain contagious up to 2 weeks after symptoms have subsided. Some people carry the bacteria for several months.

Prevention

The best preventive measures include avoiding contaminated water and food and washing hands frequently. Cooking foods and boiling water thoroughly will destroy the bacteria. It is possible to bring antibiotics prescribed by your doctor before the trip, to be taken only in case of diarrhea.

Immunization

The cholera vaccine isn't recommended very often in North America, because the infection can be easily avoided if adequate dietary precautions are taken. However, vaccination may be suggested by your physician if you are travelling to an area where the disease is common or during an epidemic or where sanitary conditions are known to be inadequate.

The currently available vaccine is administered orally and is marketed under the brand name Dukoral™. It protects against cholera and also against traveler's diarrhea caused by E. coli. It is indicated in adults and children 2 years and older. Patients take 2 or 3 doses, depending on age. Its protection starts approximately 1 week after the last dose and remains effective for 3 months for traveler's diarrhea due to E.coli and up to 2 years for cholera.

For more information:

• Public Health Agency of Canada - Travel Health