Vibrio cholerae is a bacterium that is naturally found in coastal waters. It includes various serogroups.

Serogroups O1 and O139 usually produce the cholera toxin, which can cause severe diarrheal illness. These bacteria are the cause of cholera epidemics in other parts of the world. Occasionally, BC residents who travelled to affected countries may become sick with cholera.

Other serogroups, known as V. cholerae non-O1/non-O139, can be found in coastal waters worldwide, including in BC. A small number of BC residents have become ill with V. cholerae non-O1/non-O139 after consuming contaminated BC seafood. These serogroups cause a milder diarrheal illness. Some can also cause skin or blood infections. In some cases, V. cholerae non-O1/non-O139 can produce the cholera toxin. This may result in more severe illness, but does not lead to cholera epidemics.

Cholera (V. cholerae O1/O139)

Symptoms start between a few hours to 5 days after exposure. Infection with this bacterium can cause no symptoms at all, mild to moderate diarrhea or severe symptoms in about 10% of cases. Severe symptoms include:

• Profuse painless watery diarrhea which looks like rice-water
• Profuse vomiting
• Signs of dehydration like rapid heart rate, thirst and low blood pressure which can lead to coma and death

In severe untreated infections, up to 50% of people may die due to massive loss of fluid. Treatment and rehydration brings the death rate down to less than 1%.

V. cholerae non-O1/non-O139

Symptoms start 12 to 96 hours after exposure and range from mild to moderate.

In general, symptoms tend to be milder than in cholera and include:

• Mild to moderate watery diarrhea
• Nausea and vomiting

This bacterium can also cause wound infections with pain, redness and swelling at the site of infection.

In people with weakened immune systems or with liver disease, the bacterium can infect the blood stream, causing fever, chills and a drop in blood pressure.

V. cholerae grows naturally in brackish coastal waters and estuaries. V. cholerae O1/O139 is mainly found in Asian and African coastal environments. It can contaminate fresh water sources used as drinking water. It causes epidemics in parts of the world where there is inadequate sewage and drinking water treatment. Once it affects humans, it can be spread from person-to-person through ingestion of food and water contaminated with stool.

V. cholerae non-O1/non-O139 is found in coastal environments worldwide. Infection can occur when people consume raw or undercooked seafood that has been contaminated with V. cholerae or when they accidentally swallow ocean water. The bacterium can also infect an open wound in contact with ocean water. This illness is not spread from person-to-person.

If you have severe diarrhea, diarrhea lasting more than a few days or signs of dehydration, see a healthcare provider.

In order to diagnose this infection, a healthcare provider will ask for a stool sample, which will be cultured for V. cholerae.

Most V. cholerae diarrheal infections resolve on their own. They do not require any treatment other than oral rehydration. Some patients require IV fluids to rehydrate quickly. Some infections like severe diarrhea, skin or blood infections require antibiotics to get rid of the infection.‎

Cholera (V. cholerae O1/O139)

Before travelling, visit a travel clinic and find out what diseases occur in the area you are travelling to. Most travellers are at low risk of cholera, unless they consume untreated drinking water and raw or undercooked seafood.

There is a vaccine which can decrease the risk of V. cholerae O1 infection. Discuss cholera vaccination with the travel clinic.

Follow these precautions when travelling:

• eat food from established food premises and avoid street vendors
  
• do not eat raw or undercooked seafood
• avoid uncooked foods
• use only purified or boiled water or bottled water in a sealed container; only use ice made from one of these sources
• eat only fruits that can be peeled
• wash your hands before eating and drinking; use an alcohol-based gel if you cannot wash your hands
• avoid swimming in potentially contaminated water
• carry rehydration salts

People with cholera O1/O139 can infect others. Therefore, workers in high risk occupations, like cooks and caregivers must not work while infected. Children in daycare should not attend until they are free from infection.

V. cholerae non-O1/non-O139

There is no vaccine for V. cholerae non-O1/non-O139 infection. To reduce the risk of illness, follow these steps:

• Keep seafood cold (below 4^oC) following purchase
• Rinse seafood in potable water (commercial operators and recreational harvesters, see Shellfish Safety)
• Cook shellfish and other seafood (see Vibrio parahaemolyticus for more preventive advice)

Avoid water-based activities if you have open wounds.