Information About Vibrio Bacteria

Vibrio are bacteria that occur naturally in Delaware’s brackish and marine waters, especially during warm weather months. Vibrio are a normal part of the marine ecosystem, not the result of pollution.

Vibrio infections are relatively rare in Delaware and nationwide. Individuals considered at-risk for serious Vibrio infection include small children, senior citizens, and people with certain health conditions including:

Liver disease
Alcohol abuse
Diabetes
Chronic kidney disease
Stomach disorders and inflammatory bowel disease

Cancer
Iron overload disease (hemochromatosis)
HIV/AIDS
Any illness or medical treatment that weakens the immune system

If you are unsure whether you are in the at-risk group, please consult your doctor.

For more information, please contact the DNREC Shellfish and Recreational Water Programs, at dnrec_shellfish_recwater@delaware.gov or 302-739-9939.

Contracting Vibrio

Because Vibrio occurs naturally, seawater or seafood that comes into contact with a skin cut or wound could cause a serious infection.

Vibrio wound infections are rare, and most healthy people are not at serious risk. Because infection may progress rapidly, immediate medical attention should be sought if any symptoms occur; these include fever, chills, redness, swelling, blisters, pain or skin discoloration around the wound.

Infection in individuals in the at-risk group may require limb amputation or result in death.

Vibrio infection can also be contracted through consumption of raw or partially cooked seafood, especially bivalve shellfish (oysters, clams, mussels, scallops). While Vibrio illness from shellfish is rare and generally mild in healthy people, it can be serious or fatal in those with certain medical conditions or weakened immune systems. People considered at-risk should only eat shellfish if it is fully cooked to an internal temperature of 145 degrees F for at least 15 seconds.

DNREC partners closely with the commercial shellfish industry to lower the risk of Vibrio illness by establishing Vibrio Control Plans in the warmer months.

Protect Yourself from Vibrio Infection

If you have any wounds, avoid the water.
If you go in the water, cover any wounds with waterproof bandages.
Wear water shoes to avoid cuts and scrapes.
Wear gloves or use extra care when fishing or handling crab pots or other equipment.
Wear gloves when handling raw seafood or its drippings.
If you get a cut or a scrape, get out of the water and clean it with soap and clean water, or hand sanitizer if nothing else is available.
Shower after contact with natural waters.
Wash hands before handling or eating food.
Keep shellfish iced or refrigerated under 45 degrees F.
Take care to avoid wounds when shucking shellfish.
If you are in the at-risk group for serious Vibrio infection, fully cook shellfish and other seafood to an internal temperature of 145 degrees F for at least 15 seconds.
If you have been in the water and develop symptoms, seek medical attention immediately. Tell your health care provider that you came in contact with brackish or salt water.

Does Delaware Monitor for Vibrio?

There are numerous species and strains of Vibrio bacteria, but not all of them can make people sick.

Delaware does not monitor for Vibrio because there is no numerical threshold or standard that can be linked to risk of infection. The potential for infection is variable and based on an individual’s existing health condition, so it is difficult to determine a risk standard and monitoring information would not be useful for issuing recreational water advisories

Since there is no standard that identifies risk of illness, follow the recommendations listed above to protect yourself from infection, especially when water temperatures are warm (exceeding 60 degrees F).