Information for Local Health Departments
Vibrio species are bacteria that naturally occur in marine environments or brackish water (a mixture of fresh and salt water, which is often found where rivers meet the sea and in estuaries). Infection with Vibrio can cause two distinct types of illness: cholera and vibriosis. The information on this webpage pertains to non-cholera Vibrio species and vibriosis specifically. For more information about cholera, which is caused by other strains of Vibrio (i.e., toxigenic Vibrio cholerae serogroup O1 or O139), please visit the CDC Cholera website.
More than 20 non-cholera Vibrio species can cause human illness (vibriosis), accounting for an estimated 80,000 illnesses, 500 hospitalizations, and 100 deaths each year in the United States. Non-cholera Vibrio species most frequently cause gastrointestinal illness but may also cause infections ranging from wound or ear infections to severe systemic disease.
In the U.S., the most common non-cholera Vibrio species causing vibriosis are V. parahaemolyticus, V. alginolyticus, V. vulnificus, and non-toxigenic V. cholerae. Consuming raw or undercooked shellfish is the most common cause of vibriosis. Exposing wounds to seawater or contaminated raw shellfish harvested from such waters can also cause skin or soft tissue Vibrio infection.
Vibriosis in California
Vibriosis cases in California have been reported year-round, but more than 70% of cases occur during June through October, when water temperatures are warmer. In recent years, California patients have been involved in vibriosis outbreaks due to shellfish contaminated with Vibrio, particularly oysters. While most cases of vibriosis appear to be sporadic rather than outbreak-related, there have been outbreaks associated with raw oyster consumption from certain harvest or growing areas. Thus, it is important for local health departments (LHDs) to follow up with patients with Vibrio infection.