by Catherine Krikstan
August 07, 2014
During summer months, Chesapeake Bay waters become home to a range of bacteria. One of the most talked-about bacteria is Vibrio, which occurs naturally in warm estuarine waters and can infect those who eat contaminated shellfish or swim with open wounds in contaminated waters. But illness can be avoided. Learn about the bacteria—and how to avoid infection—with this list of five Vibrio facts.
1. Vibrio is a naturally occurring bacteria. There are more than 80 species of Vibrio, which occur naturally in brackish and saltwater. Not all species can infect humans, but two strains that can have raised concern in the Bay watershed: Vibrio vulnificus and Vibrio parahaemolyticus. The bacteria are carried on the shells and in the bodies of microscopic animals called copepods.
2. The presence of Vibrio in surface waters is affected by water temperature, salinity and chlorophyll. Because Vibrio prefers warm waters, it is not found in the Bay during winter months. Instead, it is common in the summer and early fall. When water temperatures are warm, algae blooms form, fed by nutrients in the water. These blooms feed the copepods that carry the Vibrio bacteria. When the copepods die, Vibrio bacteria are shed into the water. As climate change increases the temperature of the Bay, both algae blooms and Vibrio could persist later in the season.
3. Vibrio infections can occur in people who eat raw or undercooked shellfish or who swim with open wounds or punctures in contaminated waters. While infections are rare, they do take place and can be particularly dangerous for people with compromised immune systems. The ingestion of Vibrio can cause vomiting, diarrhea and abdominal pain, and in some cases can infect the bloodstream. If an open wound or puncture comes into contact with the bacteria, the area around the wound can experience swelling, redness, pain, blistering and ulceration of the skin.
4. Infection can be avoided. To avoid Vibrio infection, follow these tips:
- Don’t eat raw or undercooked shellfish (especially during warm months).
- Avoid contact with Bay waters.
- When water contact cannot be avoided, cover wounds with waterproof bandages and wear water shoes to avoid cuts and scrapes.
- If cuts, scrapes or other wounds occur while in the water, wash immediately with clean water and soap.
- Shower after swimming in natural waters and wash hands before handling food.
5. Vibrio symptoms can start 12 to 72 hours after exposure. If you think you’ve been infected with Vibrio, seek medical attention. Make sure to let your doctor know that you have eaten raw or undercooked shellfish or crabs or have come into contact with brackish or saltwater.