Vibriosis is an intestinal disease caused by small bacteria called Vibrio , which are found in shellfish and fish dwelling in the sea or rivers and streams where they meet the ocean. Although there are several types of vibrio, V. parahaemolyticus and related species are the most common in the northwest.
Vibrio occur naturally in marine coastal waters.
Because the bacteria are more common in warmer months, shellfish and fish are more likely to be contaminated in the summer. Most cases are associated with consumption of raw or partially cooked shellfish or fish. Cooked food can be recontaminated if rinsed with seawater. Failure to keep shellfish cold after harvesting can contribute to the growth of the bacteria. Poor sanitation during preparation or improper refrigeration of seafood can also lead to illness.