Non-cholera Vibrio cholerae Infections

• What’s the difference between Vibrio cholerae that cause cholera and those that don’t?
• How do people become infected?
• What are the symptoms of infection?
• How is infection diagnosed?
• How is infection treated?
• Who is more likely to get an infection or severe illness?
• How can infection be prevented?
• How common is infection?

What’s the difference between Vibrio cholerae that cause cholera and those that don’t?

Two serogroups (O1 and O139) or types of Vibrio cholerae bacteria can produce cholera toxin that causes the disease we call cholera. About 1 in 10 people infected with cholera toxin-producing O1 or O139 Vibrio cholerae experience severe, life-threatening illness, and both serogroups can cause widespread epidemics. Learn about this severe, life-threatening illness and the serogroups that cause it.

All other Vibrio cholerae types are known as “non-cholera Vibrio cholerae.” These include strains of Vibrio cholerae O1 and O139 that do not produce cholera toxin. Most illnesses these bacteria cause are mild, and these bacteria do not cause epidemics.

How do people become infected?

Like Vibrio species that cause vibriosis, non-cholera Vibrio cholerae bacteria naturally live in coastal waters and are present in higher concentrations when water temperatures are warmer. Most infections occur during warm weather.

In the United States, most people become infected by eating raw or undercooked shellfish, particularly oysters. The bacteria also can cause an infection when an open wound is exposed to salt water or brackish water, which is a mixture of fresh and salt water that’s often found where rivers meet the sea. Learn about other Vibrio species that can cause diarrheal illness and wound infection.

Casual contact with an infected person does not put someone at risk of infection.

What are the symptoms of infection?

• Most people experience diarrhea, which can range from mild to severe and watery.
• Some people experience fever.
• People with a wound infection may experience redness and swelling at the infection site.

How is infection diagnosed?

A doctor may suspect Vibrio infection if a patient has diarrhea and has recently eaten raw or undercooked seafood, especially oysters, or when a wound infection has developed after a wound was in contact with salt water or brackish water.

Infection is diagnosed when Vibrio cholerae bacteria that do not produce cholera toxin are found in a sample of the stool, in a wound, or in the blood of the patient.

How is infection treated?

People with diarrhea should drink plenty of liquids to replace lost fluids.

Most people with non-cholera Vibrio cholerae infection recover without antibiotic treatment within a few days. However, antibiotics are sometimes used to treat people with these Vibrio infections, including people with severe or prolonged illness, those at risk of severe illness, and those with a wound infection.

Who is more likely to get an infection or severe illness?

Anyone can become infected, but those at increased risk of infection or severe illness include those who:

• Have liver disease, cancer, diabetes, HIV, or thalassemia (an inherited blood disorder)
• Receive immune-suppressing therapy for the treatment of disease
• Take medicine to decrease stomach acid levels
• Have had stomach surgery

How can infection be prevented?

The following tips can help reduce your chance of infection:

• Do not eat raw or undercooked shellfish, such as oysters.
• If you have a wound, you should avoid contact with salt water, brackish water or seafood juices from wading, fishing, or cleaning seafood. If you cannot avoid these potential exposures, cover your wound with a waterproof bandage.
• You should wash wounds with soap and water as soon as possible if they are exposed to salt water, brackish water, raw seafood, or raw seafood juices.

How common is infection?

Non-cholera Vibrio cholerae are the third most commonly reported group of Vibrio bacteria causing infection in the United States, with about 100 cases reported each year. Many more cases, however, are likely not diagnosed or reported.