Vibrios: Rare but Need to Notice
Eating raw and cold shellfish can be such enjoyment under the hot sun. Living in BC makes us have the advantaged access to fresh and tasty shellfish. However, sometimes such delicacy comes with ricks and the major ones are the toxins produced by other organisms that live with shellfish.
According to Health Canada, Vibrios are toxin-producing bacteria that can be found naturally in water, fish and shellfish. Its main transmission is through consuming contaminated foods and drinks. Most of the pathogenic Vibrios are salt-loving, which means they live in oceans. For example, Vibrio parahaemolytius that caused an outbreak in Canada in the past summer.
During May to September 2015, 82 cases of Vibrio parahaemolytius were reported (60 of them were in BC) to Public Health Agency of Canada. All cases were related to consuming raw shellfish especially oysters. Due to this outbreak, oysters harvested from British Columbia coastal waters for raw consumption on or before August 18, 2015 were recalled from the marketplace.
In response to the the outbreak, Vancouver Coastal Health issued a statement on August 2, 2015 requiring restaurants to serve oysters after cooking as only oyster harvested from BC could be served raw at that time. Fortunately, this outbreak ended fast and well. The latest case was reported on September 3 and only one person was hospitalized. No death case was reported.
Symptoms:
People infected by Vibrio parahaemolyticus usually get mild intestinal illness. After 12 to 24 hours of incubation, most people develop one or more of the following symptoms: diarrhea (watery), stomach cramps, nausea, vomiting, fever and headache. Another pathogenic type of Vibrios, V. vulnificus can cause chills, abnormal low blood pressure and bacteria present in blood to infected individuals especially to the vulnerable. Symptoms last about three days and treatments are seldom required.
More sever than two types above, people infected by V. cholerae usually develop one or more of the following symptoms after one to three days of incubation: diarrhea (watery), leg cramps, vomiting, dehydration and low blood pressure. Due to the rapid loss of body fluid, treatment (re-hydration with fluid containing electrolytes) or antibiotics in serious cases is required.
Prevention:
1. Boil shellfish in shell until open and continue boiling for 5 minutes
2. Steam until shellfish open and continue steaming for 9 minutes
3. Do not eat shellfish that is not open
4. Boil shucked shellfish for 3 minutes or fry them in oil for >10 minutes at 375°F (190°C)
5. Drink water from reliable sources
There is a video on youtube that gives a brief intro of Vibrios, check this out if you are interested:
Sources:
http://www.phac-aspc.gc.ca/phn-asp/2015/vibrioparahaemolyticus-eng.php
http://www.foodsafetynews.com/2015/08/31-vibrio-cases-prompt-bc-health-officials-to-require-cooking-of-bc-oysters/#.VkQ3_99VhBc
http://www.bccdc.ca/dis-cond/a-z/_v/Vibrio/default.htm
http://www.healthlinkbc.ca/healthtopics/content.asp?hwid=ug2972
http://healthycanadians.gc.ca/eating-nutrition/risks-recalls-rappels-risques/poisoning-intoxication/poisoning-intoxication/index-eng.php
Ya Gao, 
cvalencia, 
NorrisHuang, and 3 others are discussing.
ayra casuga 8:43 am on November 12, 2015 Permalink |
I like how your blog is about something that occurred both local and recently as this topic can easily apply to all of us living here in BC! This is a great example of how our food safety sector is doing an awesome job at monitoring potential outbreaks because of the short duration of the shellfish toxin outbreak.
TamaraRitchie 3:14 pm on November 12, 2015 Permalink |
I am curious to know how much this case cost the restaurant industry. In the summer months many tourists come to B.C to enjoy fresh seafood. Due to BC oysters not being able to be consumed raw at the end of the summer I believe many tourist would have chosen another restaurant or another type of oyster that may be more or less expensive causing a loss of income for restaurants. When outbreaks like this happen I feel many are more hesitant to consume raw oysters even after the ban is lifted.
laurenrappaport 10:42 pm on November 15, 2015 Permalink |
I remember hearing about this over the summer so its interesting to learn a bit more about it. Although I do not eat raw oysters myself, the consumption of raw oysters especially in BC seems to be on the rise. It seems like they are a hot food commodity and are in high demand especially in a city like Vancouver where we have access to such fresh seafoods. Even though this recall did not last very long, as you mentioned Vibros are naturally are found in water and more specifically, pathogenic vibros are commonly found in oceans. I wonder if this type of recall is likely to occur again and whether or not it occurs frequently?
NorrisHuang 5:11 pm on December 1, 2015 Permalink |
Raw oyster is absolutely delicious however it is sad that it is also associated with various food-borne diseases as it may be contaminated with microorganisms and toxins (as mentioned by Dr. Kitts in the guest lecture). And even though heating may be effective in terms of killing bacteria, toxins may still remain. I think the best alternative is to cook the oyster when ever possible and reduce the frequency of raw oyster consumption even though cooked oysters don’t taste as good.
cvalencia 4:34 pm on December 4, 2015 Permalink |
It’s a good thing that this is a rare case! I know a lot of friends who absolutely adore raw oysters. It is great to have awareness of such pathogens in our food, and so we can take precautions when consuming them. Hopefully restaurants can ensure that their raw oysters are free from these pathogens, to prevent the consumption of contaminated seafood. Does this pathogen also occur in other seafoods, or just mainly raw oysters? How is contamination controlled if the oysters are eaten raw?
Ya Gao 10:13 pm on December 15, 2015 Permalink |
I really enjoy eating raw oyster and now I know what caused all oyster dish to be served cooked this summer for a period of time. I am glad this is a rare case. Since the incubation period is short, the outbreak could be quickly identified and CFIA was acting fast toward the outbreak. Since this bacteria is naturally present in ocean, I am curious to know if Vibrios could also be seen from fish consumption?