City of Milwaukee Health Department investigating cases of Vibriosis related to consumption of raw oysters

MILWAUKEE – The City of Milwaukee Health Department (MHD) is coordinating an investigation with the City of Franklin Health Department, North Shore Health Department, and the Wisconsin Department of Health Services into multiple cases of Vibriosis (Vibrio parahemolyticus) related to the consumption of raw oysters. At this time, three cases have been confirmed in Milwaukee County.

Vibriosis is an illness caused by infection with Vibrio bacteria. Vibrio bacteria is naturally found in salty waters where oysters are grown and often increases in warmer weather months. Eating undercooked or raw shellfish, especially raw oysters in warm-weather months, is the main risk for acquiring Vibriosis.

Among healthy people, eating Vibrio species can cause vomiting, diarrhea, and abdominal pain. Individuals with compromised immune systems, particularly those with chronic liver disease, can face severe or life-threatening illness if infected. Symptoms usually occur within 24 hours of eating contaminated food.

The only way to kill harmful bacteria in shellfish is to cook them properly. To minimize the risk of infection, the MHD recommends that individuals:

• - Do not eat raw oysters or other shellfish
• - Cook shellfish (oysters, clams, mussels) thoroughly and order fully cooked oysters at restaurants
• - Avoid contaminating other foods with raw seafood or juices from raw seafood
• - Eat shellfish promptly after cooking and refrigerate leftovers
• - Wear protective clothing such as gloves when handling raw shellfish and wash hands thoroughly with soap and water afterward

If you have consumed raw shellfish and are experiencing symptoms, contact your health care provider.