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Notifiable Diseases On-Line

CHOLERA

Cholera is an acute enteric disease caused by the bacteria, Vibrio cholerae. Classic cholera is characterized by sudden onset of painless profuse watery diarrhea, often referred to as 'rice water stool'. If untreated , cholera can progress to rapid dehydration, circulatory collapse, renal failure and death. The infection is acquired by eating food or water contaminated by the stool or vomit of an infected person.

AGENT OF DISEASE

Epidemic cholera is caused by the bacteria Vibrio cholerae. There are two biotypes of the cholerae bacteria: the classical strain and the El Tor strain. The El Tor strain causes less severe illness than classical cholera.

SYMPTOMS

Symptoms of cholera can be quite severe and characterized by acute onset of diarrhea, which turns into a profuse watery stool, often referred to as "rice-water" stool. Untreated infections may progress to very rapid dehydration (loss of water), acidosis (a condition where the body becomes too acidic), kidney failure, circulatory collapse and death. Affected individuals need urgent rehydration with a balanced intake of fluid and salts (electrolytes) to replace those lost from the body.

PERIOD OF COMMUNICABILITY

An infected person can pass the infection to others as long as the bacteria remain in the stools, usually only a few days after recovery.

HOW IT IS TRANSMITTED

A person becomes infected with cholera by eating or drinking food or water contaminated with stool or vomit of an infected person. Sporadic cases in the United States (Louisiana and Texas) have been attributed to eating raw or inadequately cooked seafood from contaminated coastal and estuary waters.

WORLDWIDE DISTRIBUTION

The majority of cases of cholera occur in developing countries that do not have access to the level of hygiene enjoyed by industrialized countries. Asia has been particularly susceptible to outbreaks and a major outbreak occurred in South America in the early 1990s; many South American countries continue to report cases in less developed areas. Sporadic cases in North America are usually due to travellers returning from countries where cholera is still a problem.

PREVENTION/CONTROL

Persons who travel to countries where cholera is common should seek advice from a travel medicine clinic to assess their personal risk and appropriate preventive measures, if indicated. Additional information can be obtained from the Public Health Agency of Canada Travel Medicine Program website.