Calvert County Health Department

Local (410) 535-5400, DC Metro (301) 855-1353, Annapolis (410) 269-2216

Personal Health


Health Threats

Health Topics A-Z
Contact Directory
About Our Agency
Links to Organizations
Public Health
Font Size
Print this Page

Vibiro and Shewanella Algae Infections Appear in Waters Around the Chesapeake

Vibrio and Shewanella Algae bacterial infections can occur in the waters of the Chesapeake Bay and its tributaries. If not promptly treated, infections can lead to amputation or death. Vibrio and Shewanella Algae are bacterial species that naturally live in the bay, rivers, and creeks that surround Calvert County. Every year as the weather gets warmer, they multiply in the water and can cause life-threatening infections if they get into a cut or any open wound in the skin.

People over the age of 60 and anyone with a weakened immune system are particularly vulnerable to serious infections.

Vibiro infections appear in waters around the Chesapeake

Vibrio and Shewanella Algae skin and bloodstream infections:

  • Are caused by salty or brackish water
    penetrating an open wound/cut
  • People with weakened immune
    systems most at risk for severe
    symptoms or death

Signs & Symptoms:

  • Redness (may be rapid onset)
  • Ulcers, skin breakdown
  • Swelling


Take the following measures to keep yourself safe:

  • Ideally, stay away from the water if you have a fresh cut.
    Even a splash on an open cut can cause a dangerous infection.
  • If you are crabbing, wear protective gloves and boots
  • Protect open cuts with sealed coverings when in brackish or sea water
  • Seek medical care quickly if any symptoms appear (redness, swelling, tenderness). Vibrio and Shewanella Algae infections spread very quickly and can be fatal once symptoms begin to appear.


Vibrio and Shewanella Algae infections can also cause gastrointestinal (stomach) illness. These are caused by eating shellfish that have been in contact with the vibrio bacteria. The bacteria are easily killed by cooking the seafood. The bacteria do not cause an odor, so if you ate raw or undercooked seafood, you would not know about the vibrio until after you become very sick.

Here are basic cooking guidelines for cooking oysters:

  • Boil until shells open, then cook another 5 minutes
  • Steam until shells open, then steam another 9 minutes
  • Boil shucked oysters 3 minutes or fry at 375 degrees for 10 minutes


For additional information:

Site Policy | Contact Directory | Privacy Statement
975 Solomons Island Road North, PO Box 980, Prince Frederick, MD 20678 | (410) 535-5400 | Fax: (410) 535-5285
Calvert Crisis Response Hotline 1-877-467-5628
© Calvert County Health Department