WHO chimes in: Risk of Vibrio

There has been an increase in reported outbreaks and cases of foodborne disease attributed to pathogenic Vibrio species. As a result, there have been several instances where the presence of pathogenic Vibrio spp. in seafood has led to a disruption in international trade. The number of Vibrio species being recognized as potential human pathogens is increasing. The food safety concerns associated with these microorganisms have led to the need for microbiological risk assessment to support risk management decision making for their control.

V. parahaemolyticus is considered to be part of the autochthonous microflora in the estuarine and coastal environments in tropical to temperate zones. Food safety concerns have been particularly evident with V. parahaemolyticus. There have been a series of pandemic outbreaks of V. parahaemolyticus foodborne illnesses due to the consumption of seafood. In addition, outbreaks of V. parahaemolyticus have occurred in regions of the world where it was previously unreported. The vast majority of strains isolated from patients with clinical illness produce a thermostable direct haemolysin (TDH) encoded by the tdh gene. Clinical strains may also produce a TDH-related haemolysin (TRH) encoded by the trh gene. It has therefore been considered that those strains that possess the tdh and/or trh genes and produce TDH and/or TRH should be considered those most likely to be pathogenic. V. vulnificus can occasionally cause mild gastroenteritis in healthy individuals following consumption of raw bivalve molluscs. It can cause primary septicaemia in individuals with chronic pre-existing conditions, especially liver disease or alcoholism, diabetes, haemochromatosis and HIV/AIDS. This can be a serious, often fatal, disease with one of the highest fatality rates of any known foodborne bacterial pathogen.

The 41st Session of the Codex Committee on Food Hygiene (CCFH) requested FAO/WHO to convene an expert meeting to address a number of issues relating to V. parahaemolyticus and V. vulnificus including:

  • conduct validation of the predictive risk models developed by the United States of America based on FAO/WHO risk assessments, with a view to constructing more applicable models for wider use among member countries, including adjustments for strain virulence variations and ecological factors;
  • review the available information on testing methodology and recommend microbiological methods for Vibrio spp. used to monitor the levels of pathogenic Vibrio spp. in seafood and/or water; and,
  • conduct validation of growth rates and doubling times for V. parahaemolyticus and V. vulnificus in Crassostrea virginica (Eastern or American oyster) using strains isolated from different parts of the world and different bivalve molluscan species.

The requested expert meeting was held on 13-17 September 2010, and this report is the outcome of this meeting. Rather than undertaking a validation exercise, the meeting considered it more appropriate to undertake an evaluation of the existing risk calculators with a view to determining the context to which they are applicable and potential modifications that would need to be made to extend their application beyond that context. A simplified calculator tool could then be developed to answer other specific questions routinely. This would be dependent on the availability of the appropriate data and effort must be directed towards this.

The development of microbiological monitoring methods, particularly molecular methods for V. parahaemolyticus and V. vulnificus is evolving rapidly. This means the identification of any single method for the purposes of monitoring these pathogens is challenging and also of limited value as the method is likely to be surpassed within a few years. Therefore, rather than making any single recommendation, the meeting considered it more appropriate to indicate a few of the monitoring options available while the final decision on the method selected will depend to a great extent on the specific purpose of the monitoring activity, the cost, the speed with which results are required and the technical capacity of the laboratory.

The meeting considered that monitoring seawater for V. parahaemolyticus and V. vulnificus in bivalve growth and harvest areas has limited value in terms of predicting the presence of these pathogens in bivalves. A linear relationship between levels of the vibrios in seawater and bivalves was not found and whatever relationship does exist can vary between region, the Vibrio spp. etc. Also, the levels of Vibrio species of concern in seawater tend to be very low. This presents a further challenge as the method used would need to have an appropriate level of sensitivity for their detection. Nevertheless, this does not preclude the testing of seawater for these vibrios; for example, in certain situations testing can provide an understanding of the aquatic microflora in growing areas. Monitoring of seafood for these pathogenic vibrios was considered the most appropriate way to get insight into the xii levels of the pathogens in these commodities at the time of harvest. Monitoring on an ongoing basis could be expensive, so consideration could be given to undertaking a study over the course of a year and using this as a means to establish a relationship between total and pathogenic V. parahaemolyticus and V. vulnificus in the seafood and abiotic factors such as water temperature and salinity. Once such a relationship is established for the harvest area of interest measuring these abiotic factors may be a more cost-effective way of monitoring. The meeting undertook an evaluation exercise rather than attempting to validate the existing growth models. The experts considered the JEMRA growth model for V. vulnificus and the FDA growth model for V. parahaemolyticus were appropriate for estimating growth in the American oyster (Crassostrea virginica). The JEMRA growth model for V. vulnificus was appropriate for estimating growth in at least one other oyster species, Crassostrea ariakensis. The FDA model for V. parahaemolyticus was also appropriate for estimating growth in at least one other oyster species, Crassostrea gigas, but was not appropriate for predicting growth in the Sydney rock oyster (Saccostrea glomerata). There was some evidence that the V. parahaemolyticus models currently used over predict growth at higher temperatures (e.g. > 25 °C) in live oysters. This phenomenon requires further investigation. Growth model studies were primarily undertaken using natural populations of V. parahaemolyticus as these were considered to be the most representative. Data were limited and inconsistent with respect to the impact of the strain on growth rate although recent studies in live oysters suggest differences exist between populations possessing tdh/trh (pathogenic) versus total or non-pathogenic populations of V. parahaemolyticus. There was no data to evaluate the performance of the growth models in any other oyster species or other filter feeding shellfish or other seafood and as such its use in these products could not be supported. If the models are used there should be a clear understanding of the associated uncertainty. This indicated a data gap which needs to be addressed before the risk assessments could be expanded in a meaningful manner.

Risk assessment tools for vibrio parahaemolyticus and vibrio vulnificus associated with seafood, 2020

World Health Organization

https://apps.who.int/iris/bitstream/handle/10665/330867/9789240000186-eng.pdf?sequence=1&isAllowed=y

Vibrio risk model development using various water inputs

Vibrio parahaemolyticus is a leading cause of seafood-borne gastroenteritis. Given its natural presence in brackish waters, there is a need to develop operational forecast models that can sufficiently predict the bacterium’s spatial and temporal variation.

 This work attempted to develop V. parahaemolyticus prediction models using frequently measured time-indexed and -lagged water quality measures. Models were built using a large data set (n = 1,043) of surface water samples from 2007 to 2010 previously analyzed for V. parahaemolyticus in the Chesapeake Bay. Water quality variables were classified as time indexed, 1-month lag, and 2-month lag. Tobit regression models were used to account for V. parahaemolyticus measures below the limit of quantification and to simultaneously estimate the presence and abundance of the bacterium. Models were evaluated using cross-validation and metrics that quantify prediction bias and uncertainty.

Presence classification models containing only one type of water quality parameter (e.g., temperature) performed poorly, while models with additional water quality parameters (i.e., salinity, clarity, and dissolved oxygen) performed well. Lagged variable models performed similarly to time-indexed models, and lagged variables occasionally contained a predictive power that was independent of or superior to that of time-indexed variables. Abundance estimation models were less effective, primarily due to a restricted number of samples with abundances above the limit of quantification. These findings indicate that an operational in situ prediction model is attainable but will require a variety of water quality measurements and that lagged measurements will be particularly useful for forecasting.

Future work will expand variable selection for prediction models and extend the spatial-temporal extent of predictions by using geostatistical interpolation techniques.

IMPORTANCE Vibrio parahaemolyticus is one of the leading causes of seafood-borne illness in the United States and across the globe. Exposure often occurs from the consumption of raw shellfish. Despite public health concerns, there have been only sporadic efforts to develop environmental prediction and forecast models for the bacterium preharvest.

This analysis used commonly sampled water quality measurements of temperature, salinity, dissolved oxygen, and clarity to develop models for V. parahaemolyticus in surface water. Predictors also included measurements taken months before water was tested for the bacterium. Results revealed that the use of multiple water quality measurements is necessary for satisfactory prediction performance, challenging current efforts to manage the risk of infection based upon water temperature alone.

The results also highlight the potential advantage of including historical water quality measurements. This analysis shows promise and lays the groundwork for future operational prediction and forecast models.

Vibrio parahaemolyticus in the Chesapeake Bay: Operational in situ predition and forecast models can benefit from inclusion of lagged water quality measurements

Public and Environmental Health Microbiology

Benjamin J. K. Davis, John M. Jacobs, Benjamin Zaitchik, Angelo DePaola, Frank C. Curriero

DOI: 10.1128/AEM.01007-19

https://aem.asm.org/content/85/17/e01007-19.abstract?etoc

Texas man ‘skinned like a deer’ by Vibrio that killed him slowly over two weeks after fishing trip

Mia De Graaf of the Daily Mail writes a 78-year-old Texas man died after an agonizing two-week battling against flesh-eating bacteria he contracted on a fishing trip last month.

Jerry Sebek, of San Marcos, did not get in the water, did not have any open wounds, and did not have any health issues that would weaken his immune system.

And yet, hours after returning from Turtle Bay on June 13, he became delirious, vomiting, and struggling to breathe.

His daughter Kim took him to a clinic, where doctors said it looked like heat stroke.

But the next morning, he was taken to hospital, where he tested positive for vibrio, an aggressive type of bacteria that eats away at muscle and tissue.

His right arm, where the infection started, was ‘skinned like a deer,’ Kim told SanAntonio.com.

Despite amputating his arm and leg, and putting him in a medically-induced coma, doctors could not defeat the infection.

‘I’m still a little shocked and in disbelief,’ Kim told the site. 

‘Dad was a wonderful family man who loved to hunt and fish and do things out in the water.’

She added: ‘We’ve been coming here [to Turtle Bay] for years and this is just an unfortunate thing that happened.’

NZ mussels at centre of food poisoning outbreak

Seafood lovers have been warned to be careful with raw mussels after an outbreak of food poisoning.

New Zealand Food Safety announced on Friday it’s seen an uptick in the number of people contracting food poisoning from Vibrio parahaemolyticus.

Most of the people who got sick ate commercial grown mussels harvested in Coromandel.

“It is possible that the strain of vibrio parahaemolyticus is unusually aggressive, which may mean that even low numbers could cause illness,” NZ food safety director of regulation Paul Dansted said.

“Additional testing of mussels and the waters that they are being grown in is also underway to help us understand why this has happened.

“The mussels at the centre of the outbreak were all bought in their raw state, in the shell. They are not the mussels that can be bought in plastic pottles. Those mussels are cooked and marinated and are not affected.”

NZ Food Safety says people need to be careful when cooking mussels and heat them above 65C. It’s also advised to wash hands after handling shellfish, and avoid cross-contamination between raw and cooked shellfish.

Raw is risky: South Korean man, 71, had hand amputated when skin started rotting 12 hours after eating sushi

Zoe Drewett of Metro wrote in August that a man from South Korea became infected with a potentially deadly flesh-eating bacteria which caused painful black ulcers to grow across his skin 12 hours after indulging in the raw seafood. The infection was so bad that he had to have his hand and forearm amputated 25 days later.

The 71-year-old man went to hospital after two days of fever and excruciating pain in his left hand that had developed 12 hours after eating raw seafood Medics drained the blisters before deciding his limb could not be saved because the unnamed man’s skin had started rotting so badly. The pensioner visited doctors in Jeonju, South Korea, after experiencing excruciating pain in his hand for two days. His story, published in the New England Journal of Medicine, took a turn when a blister on the palm of his hand grew to 3.5cm by 4.5cm – approximately the size of a golf ball.

39 sick from Vibrio in sushi in Japan

They have a video, but this one is better.

The Japan News reports that Totoyamichi, a conveyor-belt sushi restaurant operator affiliated with Japan’s Skylark Holdings Co., — which sounds creepy enough on its own — has been shutting all 24 outlets since Monday after food poisoning occurred at some of them.

At least 39 customers have complained of food poisoning symptoms after eating at Totoyamichi restaurants.

Skylark reported the case only on its website while stopping short of holding a press conference. The restaurant group may thus come under fire for failing to fully explain the incident, analysts said.

According to Skylark, food poisoning symptoms, such as diarrhea and stomachache, were reported from customers who used eight Totoyamichi outlets in Tokyo and neighboring Kanagawa and Saitama prefectures between Aug. 31 and Sept. 3. The affected customers are recovering from their illness.

In a survey by Skylark, Vibrio parahaemolyticus, a type of bacteria that causes stomachache and other symptoms, was detected from raw sea urchin at some outlets.
 

 

Multistate outbreak of Vibrio parahaemolyticus infections linked to fresh crab meat imported from Venezuela

The U.S. Centers for Disease Control (CDC), is getting in on the vibrio outbreak linked to crab meat imported from Venezuela – often posing as Maryland crab – along with state and local health officials, and the U.S. Food and Drug Administration.

CDC recommends that consumers not eat, restaurants not serve, and retailers not sell fresh crab meat imported from Venezuela at this time.

How would consumers know? Ask questions?

Consumers are not the critical control point of this food safety system.

Yet my 9-year-old knew enough to ask if the aioli that was served with her chips at a hockey tournament in Newcastle, Australia, this was weekend, contained raw egg.

I wasn’t around, but a shiver of pride went through my body.

This type of product may be labeled as fresh or precooked. It’s commonly found in plastic containers.

Food contaminated with Vibrio parahaemolyticus usually looks, smells, and tastes normal.

Steamed crab meat from blue crab (close up)

If you buy crab meat and do not know whether it is from Venezuela, do not eat, serve, or sell it. Throw it away.

CDC, state and local health officials, and the U.S. Food and Drug Administration are investigating a multistate outbreak of Vibrio parahaemolyticus infections linked to eating fresh crab meat imported from Venezuela.

Epidemiologic evidence indicates that precooked fresh crab meat imported from Venezuela is the likely source of this outbreak.

Twelve people infected with Vibrio parahaemolyticus who ate fresh crab meat have been reported from Maryland, Louisiana, Pennsylvania, and the District of Columbia.

Four people (33%) have been hospitalized. No deaths have been reported.

Illnesses started on dates ranging from April 1, 2018 to July 3, 2018.

Food fraud: Crab meat from Venezuela linked to 9 cases of vibrio in Maryland

While Maryland Blue Crabs are a staple in the DMV, many places do sell crabs, packaged crab meat, and crab cakes with crab from elsewhere.

Anne Cutler of Fox 26 says the National Aquarium in Baltimore reports that due to environmental degradation and years of overfishing, there’s not enough blue crab in the region to support demand, and grocery stores and restaurants often resort to selling imported crab.

According to ocean conservancy organization Oceana, 33 percent of the seafood purchased in the United States is actually mislabeled.

The National Aquarium reports that under current law, crab meat can be imported from around the world, pasteurized in-state and relabeled as “Maryland crabmeat.”

Nine people have contracted dangerous Vibrio infections in Maryland alone. The state’s Department of Health is warning residents to not eat crab meat from Venezuela.

“We’re selling a lot of crab meat, shrimp, lobster, whatever you want. We’re steaming it for you. And as far as this crab meat, we gotta get it from the eastern shore now, because we heard from the media what’s going on,” said Clarence Goodman, with Jessie Taylor Seafood.

Goodman says the company is not taking any chances — sticking with products almost exclusively from the eastern seaboard. 

The crab in question comes in the little plastic tubs. Consumers should look for a label on the side of the container that says where the meat is from. If it comes from Venezuela, you don’t want to get it.

Diners should also pay attention when buying crab cakes as well.A 2015 study from Oceana found that 38 percent of crab cakes being advertised as having locally sourced Chesapeake blue crab were actually made of imported meat.

In the state of Maryland, only a few dozen restaurants in the state reliably make their crab cakes from local crabmeat and the state does not require restaurants to identify the specific source of the meat.

The state has a listing of “True Blue” local restaurants that serve Maryland blue crab.

Food safety and tourism are mutually dependent: Vibrio in conch in Bahamas

Morgan Adderley of Tribune 242 reports there have been four confirmed cases of conch poisoning and as many as six unconfirmed cases, Bahamas Health Minister Duane Sands announced yesterday.

According to Dr Sands, the exposure took place in the previous 72 to 96 hours with a number of the patients affected having eaten at Potter’s Cay.

Noting that an outbreak of conch poisoning is something the country can “ill afford” right now, Dr Sands was adamant the issue can be easily mitigated if proper hygiene is maintained.

Four cases have been confirmed via laboratory testing but Dr Sands said there are a number of unconfirmed cases – “possibly as many as six” awaiting laboratory results. He added the affected people are being treated at both Doctors Hospital and Princess Margaret Hospital, and so far, all the self-identified patients are Bahamian.

Dr Sands said the steps to controlling the outbreak lie in proper hygiene and public and vendor awareness.

“Environmental Health teams (are speaking) directly with the vendors, not only at Potter’s Cay but throughout New Providence and anywhere else that we may have reason to suspect possibility of exposure,” Dr Sands said.

“We learned back in the 1990s that this is easily controlled if people practice very simple techniques of washing conch with fresh water. And that minimises, if not eliminates the possibility of transmission.

If it’s so simple, why do so many people get sick?

Vibrio cholerae on Vancouver Island linked to herring eggs

Island Health says it is investigating confirmed cases of Vibrio cholerae infection contracted by people who ate herring eggs on Vancouver Island.

The health authority is now warning the public not to consume herring eggs found on kelp, seaweed or other surfaces that have been harvested from the French Creek to Qualicum Bay area, as they could be tainted.

Island Health did not specify how many people fell ill from eating the herring eggs or how severe their symptoms were.

Vibrio cholerae is a bacterium found in water that can cause intestinal illness including the disease cholera. 

It called the situation “unique” and said it will release more information as it becomes available.

Still waiting.