Vibriosis (Non-Cholera)

What is vibriosis?

Vibriosis is an infectious disease caused by bacteria of the Vibrio group. One particular type of Vibrio bacteria produces a toxin that causes the disease known as cholera. However, this fact sheet will discuss Vibrio infections that are not cholera.

Vibrio bacteria live in salty water and are found naturally in coastal waters. They grow and thrive in warm temperatures. They are present in higher concentrations in the water during the summer months.

How common is vibriosis?

The California Department of Public Health (CDPH) receives reports of approximately 100 to 150 cases of vibriosis each year. Infections are more common in the summer and fall months.

How does a person get vibriosis?

There are two different ways that people can become ill with vibriosis. People can get a gastrointestinal infection by eating raw or undercooked shellfish that contain the bacteria or food that has been contaminated with drippings from raw shellfish. People can also develop a skin or wound infection if they have a cut or an open wound that is exposed to contaminated seawater or drippings from shellfish. Vibriosis is not transmitted from person to person.

What are the symptoms of vibriosis?

The symptoms of vibriosis will depend on the type of infection. Gastrointestinal infections are the most common type. They usually begin within 1 day of eating contaminated food. The symptoms include watery diarrhea, abdominal cramps, nausea, vomiting, fever and chills. Most people will get better in about 3 days without medical treatment.

Skin and wound infections can range from mild to very severe and life-threatening. They usually begin 12 to 72 hours after exposure to contaminated seawater.

People with liver disease, alcoholism, or compromised immune systems are more likely to develop a severe bloodstream infection (known as sepsis) and blistering skin lesions when infected with some Vibrio bacteria, either from eating contaminated raw shellfish or from an infected wound. This severe form of infection is rare but can lead to death.

How is vibriosis diagnosed?

Your health care provider may suspect Vibrio infection if you have gastrointestinal symptoms and have eaten raw or undercooked shellfish, especially raw oysters, or if you have a wound that became infected after being in saltwater. Your health care provider can test your feces, blood, or the wound for the bacteria.

How is vibriosis treated?

Your health care provider will determine whether treatment is necessary for the infection. Treatment is not usually needed for mild diarrheal illness. It is important to drink plenty of fluids to prevent dehydration. Antibiotics are used to treat severe infections. Let your doctor know if you have liver disease or a weakened immune system so that antibiotic treatment can be started early.

What can a person do to prevent vibriosis?

Avoid eating unprocessed raw oysters or other raw shellfish, especially if you have liver disease or a weakened immune system.
Cook all oysters, clams, shrimp, and other shellfish thoroughly.
Avoid cross-contamination of cooked foods with raw seafood and juices from raw seafood.
Do not swim in or enter warm saltwater if you have a skin cut or an open wound. Avoid
exposing wounds to raw shellfish drippings.

What is public health doing about vibriosis?

Local health departments report cases of vibriosis to CDPH. When illness is associated with eating contaminated seafood, local environmental health staff investigate to determine the source of the contaminated seafood. If an outbreak occurs, CDPH can recall contaminated seafood and can close California waters or notify authorities from the states where shellfish are grown and harvested.

The CDPH Shellfish Program regularly monitors the California coastal and estuarine waters where shellfish are grown and harvested to assure that shellfish are safe for human consumption. More information on this program is available at the CDPH Shellfish Program webpage (https://www.cdph.ca.gov/Programs/CEH/DRSEM/Pages/EMB/Shellfish/Shellfish-Program.aspx)

Levels of Vibrio bacteria are high in the Gulf of Mexico during the hot summer months, and many cases of vibriosis reported in the summer have been associated with eating raw oysters harvested from the Gulf. In 2003, California passed legislation that prohibits the sale, in California, of raw oysters that have been harvested in the Gulf of Mexico during the summer months unless the oysters have been processed so that the levels of Vibrio bacteria are not detectable. This has led to a marked decrease in the number of reported cases of severe vibriosis among California residents.