Vibriosis (“vibrio”) is a rare but potentially dangerous infection associated with swimming in natural waters, particularly warm bodies of salt or brackish water such as the Chesapeake Bay and its tributaries.  Maryland averages approximately 25 cases of vibrio infection each year.

Vibrio vulnificus/CDC
Vibrio vulnificus/CDC

Vibrio may cause an infection of the skin when open wounds are exposed to warm seawater. These infections may lead to skin breakdown and ulceration. In some people vibrio may then infect the blood stream, causing a severe and life-threatening illness. This illness may be characterized by fever, chills, decreased blood pressure, and blistering skin lesions. While healthy people also can get sick, people with compromised immune systems may be at higher risk for invasion of the organism into the bloodstream and potentially fatal complications.

There are steps that can be taken to avoid this bacterial infection:

  • Wait at least 48 hours after a significant rain event before swimming, and then swim in open waters. Rain events often create high bacteria counts in natural waters due to storm water runoff.
  • Use caution and avoid swimming when the natural water temperatures rise past 80 degrees.
  • Avoid swimming in natural waters if your immune system is compromised, if you have an infection, or if you have existing cuts or sores.
  • If you are injured while swimming (e.g., cut your skin while crabbing, get scraped by a shell or sharp object), thoroughly wash the wound when you get out of the water.
  • Shower thoroughly after swimming and make sure your hands are washed before eating anything.
  • Wear gloves when handling raw shellfish or crabs and their drippings.
  • Keep open cuts and sores away from raw shellfish or crabs, their drippings, and coastal waters.
  • Do not eat raw or undercooked shellfish or crabs. Cook these items completely and throw away shellfish that do not open during cooking. Vibrio vulnificus bacteria are not a result of pollution so, although oysters should always be obtained from a reputable source, eating oysters from “clean” waters or in restaurants with high turnover does not provide protection. Only heat can destroy the bacteria.

Symptoms of vibrio can start from 12 to 72 hours after exposure. If you notice any symptoms of fever, nausea, vomiting, diarrhea, or stomach pain after eating shellfish or crabs, or if there is increased swelling, redness, pain, or blistering at the site of a cut or sore after swimming in natural waters, see a health care provider immediately.