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  • shinnie 5:18 pm on November 13, 2015 Permalink | Reply
    Tags: , , Oysters, , skin lesion, V. vulnificus, Vibrio vulnificus, Vibrios   

    Three Cases of “Flesh-eating”

    Bacterial Infections in Hong



    Three cases of necrotizing fasciitis— an infection caused by bacteria that destroys skin, fat, and the tissue covering the muscles in a short period of time—have been reported in Hong Kong during the month of July in 2015. Similar sporadic cases have also been reported in April and August of 2015 in Hong Kong. The affected include: an 82-year-old man and 78-year-old woman with underlying chronic illnesses and a 59-year-old man with good past health.

    Source: http://outbreaknewstoday.com/hong-kong-reports-3-necrotizing-fasciitis-cases-in-july-vibrio-vulnificus-the-culprit-51333/

    The causative agent is a rare but deadly pathogen, Vibrio vulnificus and its name literally translates to “causing wounds” in Latin. V. vulnificus is one of the three major species of Vibrio, with the other two being V. cholera and V. parahaemolyticus both of which are pathogens of humans.

    Vibrio vulnificus

    V. vulnificus is a Gram-negative, lactose-fermenting, opportunistic (similar to L. monocytogenes), and motile curved bacterium commonly found in marine and estuarine environments. It is a moderate halophile (requires salt for growth) and is frequently isolated from oysters, clams, crabs, and other shellfish in warm coastal waters. It is responsible for causing 95 percent of all seafood-related deaths and has a mortality rate of over 50% in North America. The mortality rates varied in Hong Kong, being 35% for septicaemia cases and 20% for wound-infection cases.

    V. vulnificus has the ability to cause wound infections, gastroenteritis, or a syndrome known as primary septicemia. Infections among healthy individuals are acute and do not have long-term consequences; ingestion of this bacterium causes mild symptoms such as vomiting, diarrhea, and abdominal pain usually within 16 hours.

    In the immunocompromised population however, V. vulnificus can trigger further complications and has the potential to invade the bloodstream from an open wound or from the gastrointestinal tract, causing primary septicemia – a severe and life-threatening illnesses. This disease is characterized by fever, chills, septic shock that is soon followed by death. The three patients affected in Hong Kong had to either undergo amputation or excisional debridement.

    V. vulnificus (There are much worse pictures than this one!)

    Individuals are considered high-risk and vulnerable to infection if they have underlying chronic diseases or liver diseases [i.e. diabetes, cirrhosis, leukemia, lung cancer, acquired immune deficiency syndrome (AIDS), AIDS- related complex (ARC), or asthma requiring the use of steroid]. They are 80-200 times more likely to develop primary septicemia than healthy individuals.

    The infective dose for healthy individuals is unidentified but for immunocompromised persons, septicemia occurs with doses of less than 100 total organisms. The incubation period is 1 – 7 days after eating and the duration of illness ranges from 2 to 8 days. Diagnostic methods are similar to those used to detect common foodborne pathogens and revolve around culturing of the organism from wounds, diarrheic stools, or blood. Methods such as the Quantitative Loop-Mediated Isothermal Amplification can quantitatively detect V. vulnificus in raw oysters with high speed, specificity, and sensitivity.

    Measures that can be taken to prevent illness include:
    • Avoid going into the ocean with open wounds (I think most people neglect this)
    • Avoid eating raw or undercooked shellfish
    • Before cooking: Discard any oysters with open shells
    • During cooking: Boil for 3-5 minutes after shells open.
    • After cooking: Discard any oysters with shells that did not open.

    There have been many sporadic cases of V. vulnificus in Hong Kong over the past decade. Although the Centre for Health Protection of Hong Kong offers various Internet resources on how to prevent V. vulnificus infections, many of the victims are the elderly and are less likely to be able to access this information. I believe that more focus needs to be directed to relaying information on opportunistic foodborne pathogens to the elderly and immunocompromised in a manner that is not via the internet, i.e. various clinics and hospitals should offer them pamphlets and communicate with them verbally. In 2013, Health Canada has collaborated with the FAO, WHO, and the government of Japan to produce expert recommendations to the Codex Committee on Food Hygiene regarding V. vulnificus. Appropriate methods to monitor environmental hygiene and hygienic production, etc. can be found in Codex Alimentarius Guidelines on the Application of General Principles of Food Hygiene to the Control of Pathogenic Vibrio Species in Seafood.

    Questions for thought:

    1. Is this pathogen present in other geographical areas?

    2. Which method(s) would be most suitable to detect the presence of this pathogen based on it transmission route?


    Codex Alimentarius (2010). International Food Standards. Guidelines on the Application of General Principles of Food Hygiene to the Control of Pathogenic Vibrio Species in Seafood. Retrieved from: http://www.codexalimentarius.org/standards/list-of-standards/

    FDA (2015). Vibrio vulnificus. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook. Retrieved from: http://www.fda.gov/Food/FoodborneIllnessContaminants/CausesOfIllnessBadBugBook/ucm070473.htm

    Han, F., Wang, F., & Ge, B. (2011). Detecting potentially virulent vibrio vulnificus strains in raw oysters by quantitative loop-mediated isothermal amplification. Applied and Environmental Microbiology, 77(8), 2589-2595.

    Lee, S. E., Kim, S. Y., Kim, S. J., Kim, H. S., Shin, J. H., Choi, S. H.. . Rhee, J. H. (1998). Direct identification of vibrio vulnificus in clinical specimens by nested PCR. Journal of Clinical Microbiology, 36(10), 2887-2892.

    Ma, J (2012). Vibrio vulnificus in food. Food Safety Focus, 72. Retrieved from: http://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_72_01.html

    Stone, J. (2015). With Global Warming, Expect More Deadly Vibrio Cases. Pharma & Healthcare. Forbes. Retrieved from: http://www.forbes.com/sites/judystone/2015/07/30/with-global-warming-expect-more-deadly-vibrio-cases/

    Treasury Board of Canada Secretariat (2015). Food and Consumer Safety Action Plan. Retrieved from: https://www.tbs-sct.gc.ca/hidb-bdih/plan-eng.aspx?Org=0&Hi=85&Pl=403

    Vibrio vulnificus (2013). Vibrio Illness (Vibriosis). Centers for Disease Control and Prevention. Retrieved from: http://www.cdc.gov/vibrio/vibriov.html

    • elaine chan 3:37 pm on November 14, 2015 Permalink | Reply

      Definitely an interesting, yet scary article! Commonly, food illnesses are related to gastrointestinal diseases, it’s my first time seeing how it can also lead to wound formation, and subsequently amputations and excisional debridements! This is definitely a wake up call for the food and marine industry to ensure the safety of their products for consumers. To determine whether or not this pathogen can be found in other geographical areas, I think it will be important to determine the pathogen’s favourable growth conditions and then evaluate which geographical areas has the potential of promoting the growth of such pathogen.

    • csontani 3:46 pm on November 14, 2015 Permalink | Reply

      This is definitely interesting to read! I’ve never heard of this pathogen before and it’s scary knowing what it can do to you. After reading this, the first question that popped in my mind was “is this pathogen a concern in where I’m currently living at?”. I certainly agreed with what you said regarding how the health agency should focus on older citizens who are immunosuppressed since they’re less likely to check the internet regarding the foods they’re eating. Maybe the food product packaging could have more information regarding the food and risks it may content or maybe health agency could talk to the senior care centre to give informations regarding these kinds of concerns.

    • angel519 10:24 pm on November 14, 2015 Permalink | Reply

      Since we live at the coast where we also consume oysters, clams, crabs, and other shellfish, and we also consume imported shellfish from warm coastal water; it is a potential pathogen that could be present at B.C. I think it is necessary to have warnings and publicize the risks of consuming contaminated shellfish to the general public. And for the high-risk population, especially the elderly, grocery stores can have brochures and signs by the shellfish section to tell them how to properly cook shellfish, symptoms of infections and to seek doctors if feel unwell after consumption. It is also important to have regular inspections on shellfish to prevent infected products spreading in the market.

    • Jasmine Lee 1:35 am on November 15, 2015 Permalink | Reply

      This pathogen is by far the most frightening of those that I have come across in this class. It is interesting to learn about a pathogen that thrives in environments with high salt levels. This is concerning since high osmolarity and low water activity are commonly used as hurdles for food safety and bacterial control. I also found it surprising that gender may play a role in regards to the pathogenicity of the V. vulnificus’ toxin. An article claimed that estrogen may assist in protecting against endotoxic shock and lowering the risk of mortality in individuals (Merkel et al., 2001). Furthermore, I agree with Angel that regular inspection of shellfish products and consumer awareness are critical for lowering the risk of exposure. It is also important to post signs along coastlines and have restaurants alert consumers about the associated risk with eating raw seafood. With many biological hazards in raw foods, I hope consumers are more diligent in terms of ensuring food safety and will make informed decisions for themselves.

      Merkel, S.M., Alexander, S., Zufall, E., Oliver, J. D. and Huet-Hudson, Y. M. (2001). Essential role for estrogen in protection against Vibrio vulnificus-induced endotoxic shock. Infection and Immunity, 69(10):6119-6122.

    • Susanna Ko 9:28 am on November 15, 2015 Permalink | Reply

      I find this article really scary because I can see my parents falling victim to this. There’s a lot of canned seafood products (clams, oysters) on the market. Cuisine with oysters is probably very popular as well. My parents like to add canned oysters into their congee. Perhaps popular asian newspapers should have a food safety section. I know my parents will probably read it.

    • cheryl lau 3:20 pm on December 4, 2015 Permalink | Reply

      This was a very scary article to read! However, I think it is necessary to point out the dangers we face when we expose ourselves to harmful microorganisms. Even though our bodies have defenses in place to fight invaders, they may not be as sound as we think. In this case, V. vulnificus caused serious consequences. I feel that most people in Hong Kong do not realize the serious affects that could follow from eating contaminated seafood. Specifically, the elderly or the people from our parents’ generation may not have been educated in food safety and I think these issues should be more prominent in the media.

    • EmilyLi 9:40 pm on December 13, 2015 Permalink | Reply

      This is a very interesting yet scary article to read. I think you title is very eye catching too. I personally like to eat seafood, and especially if you travel to coastal city like Hong Kong how could you resist the seafood there. Although in the article it mention that the pathogen is only high risk for immunocompromised individuals. However, with knowing that you are infected with a pathogen that is likely to breakdown flesh in your body is quite scary. Especially when you could catch those with just wound on you legs and going to the beach.

    • EmilyChow 3:25 am on December 15, 2015 Permalink | Reply

      It’s scary to think about these cases because they could potentially also happen here on the west coast of North America! This bacteria can possibly survive in pacific water conditions and contaminate the seafood we have here. In addition, seafood is imported and exported around the world so this is a concern for international seafood lovers. Since seafood can be enjoyed in different ways (canned, cooked, raw), it’s important to have strict processing regulations and make sure that such regulations apply for all pathogens, considering V. vulnificus is relatively rare.

  • DeniseZhang 1:58 am on November 12, 2015 Permalink | Reply
    Tags: BC, , Vibrios   

    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.

    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.

    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:


    • ayra casuga 8:43 am on November 12, 2015 Permalink | Reply

      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 | Reply

      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 | Reply

        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 | Reply

      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 | Reply

      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 | Reply

      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?

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