What is

Vibrio parahaemolyticus bacterium is in the same family as those that cause cholera. It lives in brackish saltwater and causes gastrointestinal illness in humans. About a dozen Vibrio species can cause human illness, known as vibriosis. The most common species causing human illness in the United States are Vibrio parahaemolyticusVibrio vulnificus, and Vibrio alginolyticus.

Vibrio naturally inhabits coastal waters in the United States and Canada and is present in higher concentrations between May and October when water temperatures are warmer.

2016 CDC/James Archer/Illustrator: Jennifer Oosthuizen

You can get vibriosis by eating undercooked or raw seafood, particularly oysters.

You also can get an infection if an open wound comes into contact with raw or undercooked seafood, its juices, or its drippings or with saltwater or brackish water.

Who is more likely to get

Eating raw seafood, particularly oysters, and exposing open wounds to salt water or brackish water can increase a person’s chance for getting vibriosis.

Anyone can get sick from vibriosis, but you may be more likely to get an infection or severe complications if you:

  • Have liver disease, cancer, diabetes, HIV, or thalassemia
  • Receive immune-suppressing therapy for the treatment of disease
  • Take medicine to decrease stomach acid levels
  • Have had recent stomach surgery
  • Are 65 or older

what are the symptoms
of vibriosis?

When ingested, Vibrio causes watery diarrhea often with abdominal cramping, nausea, vomiting, fever and chills.

Usually these symptoms occur within 24 hours of ingestion. Illness is usually self-limited and lasts 3 days.

Vibrio bacteria can also cause a skin infection when an open wound is exposed to salt water or brackish water. Brackish water is a mixture of fresh and salt water. It is often found where rivers meet the sea.

In the USA, the CDC estimates that about 80,000 people get
vibriosis every year
Of these, 100 die.

Diagnosis and

A clinician may suspect vibriosis if a patient has watery diarrhea and has recently eaten raw or undercooked seafood, especially oysters, or when a wound infection occurs after exposure to seawater. Infection is diagnosed when Vibrio bacteria are found in the stool, wound, or blood of a patient who has symptoms of vibriosis.

Treatment is not necessary in mild cases, but patients should drink plenty of liquids to replace fluids lost through diarrhea. Although there is no evidence that antibiotics decrease the severity or duration of illness, they are sometimes used in severe or prolonged illnesses.

is vibriosis a serious disease?

Most people with a mild case of vibriosis recover after about 3 days with no lasting effects.

However, people with a Vibrio vulnificus infection can get seriously ill and need intensive care or limb amputation

About 1 in 5 people with this type of infection die, sometimes within a day or two of becoming ill.

you can
Reduce your risk of vibriosis

How common is a vibrio infection?

An estimated 4500 cases of Vibrio infection occur each year in the United States.

However, the number of cases reported to CDC is much lower because surveillance is complicated by underreporting.

To improve our ability to monitor trends, infections caused by V. parahaemolyticus and other Vibrio species became nationally notifiable in 2007. State health departments report cases to CDC, and these reports are summarized annually.

what foods are commonly linked to vibriosis?

Vibrio bacteria naturally live in coastal waters and can concentrate inside shellfish and other seafood that live in these waters.

  • Oysters: Oysters feed by filtering water. As oysters feed, Vibrio, norovirus, and other germs can concentrate in them. When you eat raw or undercooked oysters, germs that may be in them can make you sick. 
  • Other shellfish: Oysters aren’t the only shellfish that can carry Vibrio and other germs. Vibrio illnesses have also been linked to crawfish, crab meat, and other shellfish including clams, mussels, and scallops. 
  • Fish: Although Vibrio infections from fish aren’t as common as infections from shellfish, they do happen from time to time. Other harmful germs can be found in fish, too. To help prevent infection, cook fish to 145°F or until its flesh is opaque.

You can reduce your risk of vibriosis by following these tips:

  • Don’t eat raw or undercooked oysters or other shellfish. Cook them before eating.
  • Always wash your hands with soap and water after handling raw shellfish.
  • Avoid contaminating cooked shellfish with raw shellfish and its juices.
  • Stay out of salt water or brackish water if you have a wound (including from a recent surgery, piercing, or tattoo), or cover your wound with a waterproof bandage if there’s a possibility it could come into contact with salt water or brackish water, raw seafood, or raw seafood juices. Brackish water is a mixture of fresh and salt water. It is often found where rivers meet the sea.
  • Wash wounds and cuts thoroughly with soap and water if they have been exposed to seawater or raw seafood or its juices.
  • If you develop a skin infection, tell your medical provider if your skin has come into contact with salt water or brackish water, raw seafood, or raw seafood juices.

If you are in a group more likely to get vibriosis:

  • Wear clothes and shoes that can protect you from cuts and scrapes when in salt water or brackish water.
  • Wear protective gloves when handling raw seafood.
What was meant to be a romantic, relaxing meal to celebrate a special occasion became unforgettable for entirely different reasons when Dona became violently ill from eating oysters contaminated with Vibrio parahaemolyticus.​ Dona’s illness was part of an outbreak that affected 300 people and ultimately killed six. Dona spent a week in hospital before she could return home, and spent another six months recuperating at home before she could work again.
Read the whole story
check out more from the CDC
You might have heard people say that you should eat oysters or others shellfish only in months with the letter "R"
But remember that Vibrio and other bacteria (and viruses) that affect seafood can can cause illness in any month, so follow basic food safety tips all year long.