Vibrio parahaemolyticus (Vp) Gastrointestinal Illness

Eating contaminated Shellfish can be life threatening: Always check for Marine Biotoxin and Sanitary Contamination Closures if you plan on harvesting and consuming any shellfish.

Go to the latest Biotoxin Contamination update

Characteristics of the Illness

Vibrio parahaemolyticus (Vp), a naturally occurring bacterium found in shellfish, is present in higher concentrations during the summer months when water temperatures rise. As outdoor temperatures increase, so does the risk of illness associated with eating raw or undercooked bivalve shellfish (e.g. oysters, clams, mussels, scallops, and cockles). To reduce the risk of illness, only harvest shellfish at the water’s edge when the tide is going out, refrigerate or freeze immediately, and cook thoroughly before consuming. Vibrio parahaemolyticus can be present in bivalve shellfish even in harvest areas that are open and approved for shellfish harvesting. When people consume raw or undercooked bivalve molluscan shellfish, especially oysters, they could be susceptible to infection by Vibrio parahaemolyticus.  

For more information please see the BC Centre for Disease Control website


The symptoms of Vibrio parahaemolyticus infection may include watery diarrhea, stomach cramps, nausea, vomiting, fever, and headache. Symptoms usually start within 12 to 24 hours and last up to 3 days.  

At the first sign of such symptoms, contact your Poison Control Center at 1-800-567-8911 for first aid advice and seek medical attention immediately.

Guidelines for cooking bivalve shellfish

  • Boil oysters, clams, scallops, mussels and cockles until the shells open, and then boil for an additional 3-5 minutes. You should also boil or simmer shucked shellfish for at least 3 minutes or until the edges curl.
  • Steam for 4-9 minutes and throw out those that did not open.
  • Fry for at least 3 minutes at 190°C (375°F).
  • Bake for at least 10 minutes at 230°C (450°F)

Control Measures

The single most effective control measure is responsible harvesting and food preparation before consumption.  Always ensure that molluscan bivalve shellfish come only from open harvest areas. However, be aware that Vibrio bacteria may be present in areas that are open for harvest. Proper cooking of bivalves is the best way to reduce the risk of illness from Vibrio infection.

Call before you harvest
Information is also available on the Fishery Report Record Line at: 1-866-431-3474.

For more information, please visit the Canadian Shellfish Sanitation Program page (Canadian Food Inspection Agency site).


For more information about Shellfish Closures, please contact :

Phone: 250-756-7192

Resource Management
Canadian Shellfish Sanitation Program (CSSP) Coordinator
DFO South Coast Division
3225 Stephenson Point Rd.
Nanaimo, BC V9T 1K3

Phone: 250-339-3799
Fax: 250-339-4612

Resource Management
DFO South Coast Division
148 Port Augusta St.
Comox, BC V9M 3N6

Phone: 604-666-1746

Communications Advisor

Shellfish Toxin Updates

Toll free: 1-866-431-FISH

Recorded information

or visit your local DFO Office.