What is Vibrio parahaemolyticus? 

Vibrio paraheamolyticus is a  bacterium in the same family as those that cause cholera. It lives in brackish saltwater and causes gastrointestinal illness in humans. V.  parahaemolyticus naturally inhabits coastal waters in the United States and Canada and is present in higher concentrations during summer; it is a halophilic, or salt-requiring organism.

What type of illness is caused by V. Paraheamolyticus?

When ingested, V. Paraheamolyticus 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. Severe disease is rare and occurs more commonly in persons with weakened immune systems. V.  parahaemolyticus can also cause an infection of the skin when an open wound is exposed to warm seawater.

How does infection with V. parahaemolyticus occur? 

Most people become infected by eating raw or undercooked shellfish, particularly oysters. Less commonly, this organism can cause an infection in the skin when an open wound is exposed to warm seawater.

How common is infection with V.  parahaemolyticus?

In Asia, V. parahaemolyticus  is a common cause of foodborne disease. In the United States, it is less commonly recognized as a cause of illness, partly because clinical laboratories rarely use the selective medium that is necessary to identify this organism. Not all states require that V.parahaemolyticus infections  be reported to the state health department, but CDC collaborates with the Gulf Coast states of Alabama, Florida, Louisiana, and Texas to monitor the number of cases of Vibrio infection in this region. From those states, about 30-40 cases of V.  parahaemolyticus infections are reported each year. The Foodborne Diseases Active Surveillance Network, Food Net, also tracks V.parahaemolyticus in regions outside the Gulf Coast. In 1997, the incidence of diagnosed V. parahaemolyticus infection in Food Net sites was .25/100,000.