Croatia’s prime oyster farmers in alarm after norovirus discovered

Posted on March 26, 2019 by Douglas Powell

I’m not sure who decided raw oysters were a food, because that gelatinous slime is gross.

Oysters are also vulnerable to norovirus.

Authorities have detected norovirus, which causes diarrhea and vomiting, in parts of the Mali Ston bay in Croatia—triggering shock and alarm among the breeders.

The traditional oyster-tasting feast in March has been canceled and fears are mounting of huge financial losses to the local community that harvests about 3 million oysters each year.

Experts are pointing their fingers at the outdated sewage system in the area that has seen a rise in the numbers of tourists flocking to Croatia’s stunning Adriatic coast.

“I am really sorry but people themselves are to blame that something like this happened,” explained Vlado Onofri from the Institute for Marine and Coastal Research in nearby Dubrovnik. “It’s something that has to be solved in the future.”

While some stomach bugs can be eliminated with cooking, norovirus survives at relatively high temperatures.

Navigating the oyster fields in their small boats, the farmers proudly show visitors rows and rows of oyster-filled underwater farm beds spreading through the bay.

Top municipal official Vedran Antunica questioned the assumption that the local sewage system was to blame for the outbreak.

“Viruses are everywhere, now as we speak, the air is full of viruses,” Antunica said. “We had the same sewage system in the past, so why wasn’t it (norovirus) recorded? What has changed?”

Some would call it knowledge.

And we’re all hosts on a viral planet.

Florida Vibrio vulnificus cases reach 30, Canadian growers upset with ban

Posted on September 13, 2015 by Douglas Powell

As the number of Vibrio cases in Florida hit 30, and 81 in western Canada in a separate outbreak, producers of shellfish in B.C. say they cutting jobs because of a month-long raw oyster ban in Vancouver.

Roberta Stevenson, executive director of the B.C. Shellfish Growers Association says producers are testing the oysters and they meet health requirements, so the ban should be lifted.

“They are tested five times more than they used to be with the new Health Canada guidelines that are more stringent. So we are 100 per cent confident that before those oysters leave that processing plant they are completely safe to eat,” she said.

Local oysters are being sold to customers in the rest of Canada and to the U.S., Stevenson said, so she doesn’t understand why Vancouver Coastal Health isn’t lifting the ban.

If you’re so confident in your data, make it pubic and market food safety at retail.

“We will lift the order when public health officials in B.C. are satisfied that oyster conditions in coastal waters are not at a level to be a food safety concern,” said Vancouver Coastal Health in a statement.

Bad idea: Raw oysters in nursing homes

Posted on August 19, 2015 by Douglas Powell

With at least 67 sick from Vibrio parahaemolyticus linked to raw oysters in Canada and a full recall being launched by the Canadian Food Inspection Agency, one has to wonder why raw oysters would be served in a nursing home.

But that’s what happened in France in 2012.

Researchers report that the presence of norovirus in shellfish is a public health concern in Europe. Here, we report the results of an investigation into a norovirus gastroenteritis outbreak following a festive lunch which affected 84 (57%) residents and staff members of a nursing home in January 2012 in France. Individuals who had eaten oysters had a significantly higher risk of developing symptoms in the following 2·5 days than those who had not, the risk increasing with the amount eaten [relative risk 2·2 (1·0–4·6) and 3·3 (1·6–6·6) for 3–4 and 5–12 oysters, respectively].

In healthy individuals during those days, 29 (32%) subsequently became ill, most of whom were staff members performing activities in close contact with residents. Genogroup II noroviruses were detected in fecal samples, in a sample of uneaten oysters and in oysters from the production area. Identifying a norovirus’s infectious dose may facilitate the health-related management of contaminated shellfish.

A norovirus oyster-related outbreak in a nursing home in France, January 2012

Epidemiology and Infection / Volume 143 / Issue 12 / September 2015, pp 2486-2493

Loury, F. S. Le Guyader, J. C. Le Saux, K. Ambert-Balay, P. Parrot and B. Hubert

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9888431&utm_source=Issue_Alert&utm_medium=RSS&utm_campaign=HYG

31 sick: Restaurants ordered to cook all oysters from B.C.

Posted on August 13, 2015 by Douglas Powell

Vancouver Coastal Health has ordered restaurants to stop serving raw oysters from local waters in response to a rising tide of foodborne illness caused by vibrio parahaemolyticus, a bacteria that naturally occurs in shellfish.

According to an advisory issued Wednesday, 31 cases connected to raw oysters have been reported in B.C. so far this year, although the actual number is likely much higher because not all cases are reported.

Symptoms include diarrhea, cramps, vomiting and fever that can last up to a week.

VCH has ordered restaurants to cook all B.C. oysters and said only oysters from outside the province can be served raw. The order comes as the BC Centre for Disease Control issued a similar warning asking consumers to avoid eating locally harvested oysters raw.

“Normally we see between eight and 10 cases in (June and July),” said Marsha Taylor, an epidemiologist with the BCCDC. “So there has been a really notable increase this year.”

Raw still risky: 102 sickened with Norovirus in oysters at Taiwan restaurant

Posted on July 16, 2015 by Douglas Powell

A recent diarrhea outbreak among 102 tourists on Green Island off Taitung was caused by a norovirus infection at a local seafood restaurant that had served contaminated raw oysters imported from South Korea, Taiwan’s Food and Drug Administration (FDA) reported Thursday.

Taitung health authorities have received seven suspected food poisoning cases between June 26-30 which involved 102 tourists in six tour groups who displayed symptoms of diarrhea, with 76 of whom having been hospitalized.

After an investigation, Taitung County’s Public Health Bureau found that all the 120 people had eaten raw oysters at a seafood restaurant on Green Island and directed that all restaurants around the island to stop serving raw oysters.

In addition, two raw oyster samples have been found with the presence of norovirus, while two travelers who visited local hospitals tested positive for the norovirus, according to a report from the FDA on July 8.

The FDA then traced the sources of the contaminated products and found they were among a total of 16,447.5 kilograms of raw oysters imported by two aquaculture companies in New Taipei and Kaohsiung from South Korea, a FDA official said Thursday.

New regs to control Vibrio in raw oysters

Posted on May 24, 2015 by Douglas Powell

I don’t eat raw oysters.

Lifelong Brisbane residents I know will not eat oysters, raw or cooked (and we have an abundant supply — of oysters, and lifelong Brisbane residents).

JoNel Aleccia of The Seattle Times writes that when a work trip sent Jill Poretta to Seattle two summers ago, the New Jersey resident decided to make a vacation of it, a chance to see the sights and enjoy the city’s fine dining.

But an appetizer plate of mixed oysters soon spoiled the trip. The day after her dinner at a restaurant on the central waterfront, Poretta became so violently ill she had to take a cab to a hospital at 3 a.m.

“I couldn’t get out of the car,” recalled the 43-year-old legal researcher from Haddonfield, N.J. “I’m vomiting as soon as I walk in the door.”

Poretta had to cut short her trip and head home, where she says she felt exhausted and ill for two weeks. Tests showed she’d contracted Vibrio parahaemolyticus, known as Vp, a leading cause of seafood poisoning in the U.S.

In July 2013, her case was one of four traced to Hammersley Inlet, an arm of water in southwest Puget Sound. State health officials closed the shellfish-growing area — but only after Poretta and others had gotten sick.

Starting this month, there’s a new approach — a first-in-the-nation effort by state health officials and shellfish growers — to curb heat-loving Vp long before it hits the plate. It requires quicker cooling of oysters when air and water temperatures get too warm and closing at-risk commercial beds before illnesses occur.

The protocol requires real-time monitoring to determine how fast harvested oysters must be cooled to a safe 50 degrees — and when they shouldn’t be gathered at all.

The rules aims to reduce the 40 to 45 infections tied to Washington oysters that are confirmed each year and another 6,000 to 7,000 cases that go undiagnosed, health officials said.

“Anytime you’re basically waiting for illnesses to trigger an action, it means you’ve missed your peak window for public-health protection,” said Laura Wigand Johnson, a marine and environmental scientist who led the state’s two-year process to put the Vp procedures in place.

But the new strategy, which took effect May 1 and runs through Sept. 30, has sent ripples of concern through Washington state’s commercial shellfish industry. That includes 329 licensed private growers and 39 tribal producers, though only about 150 deal in oysters, Johnson said.

All say they are in favor of reducing hard-to-predict Vp illnesses, even as they acknowledge the move requires new duties, new documentation and extra staff.

“It’s quite a shift in the way we do business as it relates to oysters for raw consumption,” said Bill Dewey, a spokesman for Shelton-based Taylor Shellfish Farms, the largest producer of farmed shellfish in the U.S. “We’re working through the nuts and bolts of how we do it.”

Those nuts and bolts apply to shellfish harvesters and dealers who supply fresh oysters to market to be eaten raw, not oysters designated for shucking or post-harvest processing.

There’s lots more at http://www.seattletimes.com/seattle-news/health/tighter-rules-aim-to-limit-seafood-poisoning-from-raw-oysters/

I don’t eat raw oysters: Iron overload disease causes rapid growth of Vibrio

Posted on January 14, 2015 by Douglas Powell

Every summer, the news reports on a bacterium called Vibrio vulnificus found in warm saltwater that causes people to get sick, or die, after they eat raw tainted shellfish or when an open wound comes in contact with seawater.

People with a weakened immune system, chronic liver disease or iron overload disease are most at risk for severe illness. Vibrio vulnificus infections in high-risk individuals are fatal 50 percent of the time.

Now, researchers at UCLA have figured out why those with iron overload disease are so vulnerable. People with the common genetic iron overload disease called hereditary hemochromatosis have a deficiency of the iron-regulating hormone hepcidin and thus develop excess iron in their blood and tissue, providing prime growth conditions for Vibrio vulnificus.

The study also found that minihepcidin, a medicinal form of the hormone hepcidin that lowers iron levels in blood, could cure the infection by restricting bacterial growth.

The early findings were reported online Jan. 14 in the journal Cell Host and Microbe.

“This is the first time that the association of hepcidin deficiency and susceptibility to Vibrio vulnificus infection was tested,” said senior author Dr. Yonca Bulut, a clinical professor of pediatrics at Mattel Children’s Hospital at UCLA and a researcher with the UCLA Children’s Discovery and Innovation Institute. “The dramatic effectiveness of the new treatment, even after the infection was established, was impressive.”

To conduct the study, researchers compared the fatality of Vibrio vulnificus infection in healthy mice with mice that lacked hepcidin, modeling human hereditary hemochromatosis. The results showed that the infection was much more lethal in hepcidin-deficient mice because they could not decrease iron levels in the blood in response to infection, a process mediated by hepcidin in healthy mice.

Giving minihepcidin to susceptible hepcidin-deficient mice to lower the amount of iron in the blood prevented infection if the hormone was given before the Vibrio vulnificus was introduced. Additionally, mice given minihepcidin three hours after the bacterium was introduced were cured of any infection.

Hereditary hemochromatosis is a genetic disease that causes the body to absorb and store too much iron. It affects as many as 1 in every 200 people in the United States. Since it can take decades for the body to store damaging levels of iron, many people may not be aware that they have the disease until signs of the condition begin to appear later in life.

The co-directors of the UCLA Center for Iron Disorders, Dr. Tomas Ganz, a professor of medicine and pathology at the David Geffen School of Medicine at UCLA, and Elizabeta Nemeth, a professor of medicine at UCLA, led the invention of minihepcidins at UCLA. Minihepcidins are being developed for treatment of iron-overload disorders, such as hereditary hemochromatosis and Cooley’s anemia. The use of minihepcidin to treat potentially lethal infections is a possible new application.

“We found that hepcidin is required for resistance to a Vibrio vulnificus infection,” said the study’s lead author Joao Arezes, a visiting graduate student from the University of Porto in Portugal. “The development of the treatment tested in mouse models could reduce the high mortality rate of this disease.”

The next stage of research is to understand why Vibrio vulnificus bacteria become so lethal when iron levels are high, and to learn which other microbes respond similarly to excess iron.

Journal reference: Cell Host and Microbe

Provided by University of California, Los Angeles

Raw remains risky: Hong Kong investigating raw oyster outbreaks

Posted on December 25, 2014 by Douglas Powell

While waiting in line on Dec. 24 for our Xmas seafood, our local fishmonger was offering raw oysters.

I said, no thanks.

The Hong Kong Centre for Food Safety (CFS) of the Food and Environmental Hygiene Department today (December 25) reminded the public to pay attention to food safety to prevent food-related illness during holidays and seasonal celebrations. Susceptible groups, such as the elderly, young children, pregnant women, and people with weakened immune systems or liver diseases, should avoid eating high risk food like raw oysters.

A CFS spokesman said, “The CFS received referrals from the Centre for Health Protection on two suspected food poisoning clusters recently. Raw oysters were among the suspected food items in both outbreaks.

Upon CFS’ request, sale of raw oyster was suspended on both food premises. The CFS is also tracing the source and distribution of the raw oysters in question.”

104 sickened: increase in Vibrio parahaemolyticus infections associated with consumption of Atlantic coast shellfish — 2013

Posted on April 18, 2014 by Douglas Powell

I don’t eat raw oysters. This is why.

The U.S. Centers for Disease Control reports Vibrio parahaemolyticus (Vp) is found naturally in coastal saltwater. In the United States, Vp causes an estimated 35,000 domestically acquired foodborne infections annually (1), of which most are attributable to consumption of raw or undercooked shellfish. Illness typically consists of mild to moderate gastroenteritis, although severe infection can occur. Demographic, clinical, and exposure information (including traceback information on implicated seafood) for all laboratory-confirmed illnesses are reported by state health departments to CDC through the Cholera and Other Vibrio Surveillance system. Vp isolates are distinguished by serotyping (>90 serotypes have been described) and by pulsed-field gel electrophoresis (PFGE).

Vp serotypes O4:K12 and O4:K(unknown) comprise the Pacific Northwest (PNW) strain and, within the United States, had not been associated with shellfish outside the Pacific Northwest before 2012. During May–July 2012, Vp of the PNW strain associated with shellfish from Oyster Bay Harbor in New York caused an outbreak of 28 illnesses in nine states. Simultaneously, Vp of the PNW strain caused an outbreak of illnesses on a cruise ship docked on the Atlantic Coast of Spain; illness was associated with cooked seafood cooled with ice made from untreated local seawater. All Vp isolates from ill persons in the U.S. and Spanish outbreaks that were further subtyped were indistinguishable by PFGE (2).

In 2013, this same indistinguishable strain was traced from shellfish consumed by ill persons to a larger area of the U.S. Atlantic Coast, causing illness in 104 persons from 13 states during May–September (Figure). The median age of patients was 51 years (range = 22–85 years); 62% were male. Six (6%) patients were hospitalized; none died. Multiple outbreaks appeared to be occurring, accounting for many of these illnesses. Illness was associated with consumption of raw shellfish and seafood traceback was reported for 59 (57%) illnesses. Of these illnesses, 51 (86%) involved seafood that could be definitively traced to a single harvest area. The implicated harvest areas were located in Connecticut (20 illnesses), Massachusetts (15), New York (10), Virginia (four), Maine (one), and Washington (one). The remaining eight illnesses with traceback information involved seafood that could not be definitively traced to a single harvest area (locations reported included harvest areas of the Atlantic Coast of the United States and Canada). In response to the illnesses, four Atlantic Coast states closed implicated harvest areas; two issued shellfish recalls (3). The number of foodborne Vp cases in the United States traced to Atlantic Coast shellfish was threefold greater in 2012 and 2013 compared with the annual average number reported during 2007–2011.

This PNW strain is possibly becoming endemic in an expanding area of the Atlantic Ocean. The mechanisms for this introduction are not known. During the 2014 Vibrio season, beginning in the spring, clinicians, health departments, and fisheries departments should be prepared for the possibility of shellfish-associated diarrheal illness caused by this strain again. Appropriate actions, such as quick closure of implicated harvest areas, will help prevent additional illnesses. The Interstate Shellfish Sanitation Conference maintains a list of shellfish harvest area closures and recalls.* Clinicians seeking an etiology of diarrhea in a patient who has recently consumed raw or undercooked shellfish should notify the microbiology laboratory that Vp is suspected; the use of special culture media (thiosulfate citrate bile salts sucrose) facilitates identification of Vibrio species. Consumers can reduce their risk for Vp infection by avoiding eating raw or undercooked shellfish, especially oysters and clams.†

References

Scallan E, Hoekstra RM, Angulo FJ, et al. Foodborne illness acquired in the United States—major pathogens. Emerg Infect Dis 2011;17:7–15.

Martinez-Urtaza J, Baker-Austin C, Jones JL, Newton AE, Gonzalez-Aviles GD, DePaola A. Spread of Pacific Northwest Vibrio parahaemolyticus strain. N Engl J Med 2013;369:1573–4.

CDC. Increase in Vibrio parahaemolyticus illnesses associated with consumption of shellfish from several Atlantic coast harvest areas, United States, 2013. Atlanta, GA: US Department of Health and Human Services, CDC; 2013. Available at http://www.cdc.gov/vibrio/investigations/index.html.

* Available at http://www.issc.org/closuresreopenings.aspx.

† Additional information available at http://www.cdc.gov/vibrio/investigations/vibriop-09-13/advice-consumers.html.

CDC MMWR 63(15);335-336

Anna E. Newton, Nancy Garrett, Steven G. Stroika, Jessica L. Halpin, Maryann Turnsek, Rajal K. Mody

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6315a6.htm?s_cid=mm6315a6_e

2 sick; oyster farmers back in business

Posted on October 6, 2013 by Douglas Powell

Katama Bay oyster beds in Massachusetts have been reopened a month after closing because of links to at least two Vibrio illnesses.

Katama oysters should be back in the restaurants by Columbus Day. “I’m really happy for all the farmers and I’m certainly relieved,” said Jack Blake, owner of Sweet Neck Farm, in a telephone call with the Times Friday evening, as his wife Susan cheered in the background.

“We haven’t stopped working; I’ve watched the sun rise every day. We’ve been getting our market size oysters ready to go. We have to empty some cages because we need the room, the seed is growing fast.” Mr. Blake said the Offshore Ale Company and The Lookout Tavern could be serving his oysters as early as tomorrow. “

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