Norovirus Outbreak Leads Lousiana Officials to Shut Down Oyster Harvest

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The closures came quickly last month. Oyster harvest areas in four Louisiana parishes south of New Orleans have been closed since late March. Areas off limits are located in Plaquemines, St. Bernard, Jefferson and Lafourche parishes.

raw-oysters-featured.jpgThe areas are on the Gulf Coast in locations both east and west of the Mississippi.

Harvest zones closed are numbers 3,7, and 13–all were put off limits to harvesters on the order of Dr. Jimmy Guidry, the state health officer. Guidry began signing closure orders when outbreaks of norovirus sickened more than 50 in both New Orleans and Pascagoula.

People struck with norovirus are usually hit with severe flu-like symptoms including fever, chills, aches, nausea, and diarrhea lasting for a couple of days. Recovery usually follows in short order.

Health officials in Louisiana and Mississippi say they cannot be sure oysters were to blame, but closed the suspected areas as a precaution.

For Area 7, Guidry not only put the harvesting of molluscan shellfish off limits, but also ordered a recall of all shucked, frozen, breaded, and post-harvest processed oysters, and oysters for the half shell market.

The earliest any of the areas could re-open would be later this week. So far, the closures have not had any noticeable impact on the availability of oysters at any of the Gulf Coast’s many raw bars.

New Orleans, however, is just ten days away from its 41st Annual Jazz Festival, an event that will bring thousands of visitors to the Big Easy to hear music by hundreds of musicians including Simon & Garfunkel, B.B. King, and Pearl Jam. When not at the festival, many of those visitors will be out looking for authentic raw oysters.

Louisiana requires harvesters to keep logs of the waters where oysters originated and where they are sold. Sewage runoff can lead to high fecal coliform levels in Gulf waters, causing the norovirus contamination.

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Scientists are concerned that dinophysis acuminata, an algae normally seen on reefs in the North Sea, has made its way to the Gulf Coast.When Alabama officials closed state waters to oystering last week, it marked just the second time one of the nation’s oyster reefs had been shut down because of a one-celled organism that causes diarrhetic shellfish poisoning.

Scientists fear members of the Dinophysis family of algae represent an emerging threat on the Gulf’s shellfish beds, one that could force closures during the height of the winter harvest season.

Dinophysis acuminata, which was found last week on Alabama oyster reefs, is typically seen in colder oceans such as the North Sea. It is a common problem in Scandinavian countries, where its presence can force the closure of mussel beds for weeks or months at a time.

People eating infected oysters may experience abdominal cramping, nausea, vomiting and diarrhea — sometimes as quickly as 30 minutes after consumption. Unlike the viruses and bacteria that can sicken people who eat raw oysters, the acid that causes diarrhetic shellfish poisoning does not disappear when oysters are cooked, meaning even cooked oysters from infected beds can cause illness.

Scientists found 3,800 cells of the algae per liter of water in Grand Bay during routine sampling around the oyster reefs there on March 30. At concentrations over 1,000 cells per liter, shellfish, including oysters, accumulate high levels of the algae in their tissue as they filter water to feed.

“We consulted with the FDA. They said we should close the reefs, so we did,” said Jeff McCool with the seafood branch of the Mobile County Health Department. “The FDA went back a few days later and tested in Grand Bay. All their samples came back negative.”

The Alabama reefs reopened Friday morning.

Texas oyster reefs were closed for a month because of a 2008 bloom of another member of the Dinophysis family, the first time a U.S. shellfish bed was closed for Dinophysis contamination. Scientists believe it reached American waters via the ballast water of ships from Europe.

The FDA attributed a recent rash of oyster-related illnesses in Louisiana and Mississippi to the more-common norovirus. But some biologists have speculated they are actually cases of diarrhetic shellfish poisoning linked to algae blooms, such as the one last week in the Mississippi Sound. FDA officials did not return calls seeking comment.

The two illnesses have identical symptoms lasting one to two days. The primary difference is the speed with which a person becomes sick — norovirus typically takes 24 to 48 hours to incubate, while diarrhetic shellfish poisoning usually takes less than 24 hours.

Norovirus is commonly known as the stomach flu. It can be passed from person to person and is the culprit behind the mass sickness episodes seen on cruise ships.

Three of Louisiana’s seven oyster harvesting areas were shut down in the last few weeks, with norovirus blamed. It is unclear if Louisiana officials looked for D. acuminata. Neither Louisiana nor FDA officials responded to questions about sampling on those reefs.

Ed Cake, an oyster biologist registered with the state of Louisiana, said he believed the disparate locations of the affected Louisiana reefs suggest diarrhetic shellfish poisoning.

“We’ve had an extremely cold winter, plus a lot of rain that put a lot of nutrients in the water. That’s a recipe for these algae blooms, not norovirus. The only way to get norovirus on all these reefs is for an infected person to spread it to each reef,” Cake said. “The problems are too widespread to be caused by people vomiting or going to the bathroom overboard on the reefs.”

Reefs must be infected by humans with norovirus for there to be an outbreak, Cake said, while algae blooms can occur without any help from people. He also noted that there have been a number of dinoflagellate blooms along the Atlantic seaboard this year, most attributable to excess nutrients washed into the sea by unusually heavy rainfall.

In e-mail exchanges with oyster biologists and Alabama officials, FDA scientists said that, based on the time it took for people to get sick in the several episodes this year, they believed people were afflicted with norovirus.

In those e-mails, an FDA scientist acknowledged that the agency had little experience with Dinophysis because it is so seldom seen in the United States, and he held out the possibility that the incubation time for diarrhetic shellfish poisoning may not be fully understood.

“This thing is here now so we are adding it to our list of things we look for in our routine samples,” said McCool, with the Mobile health department. “It’s just a good idea.”

Scott Gordon, head of the Mississippi Shellfish Bureau in the Department of Marine Resources, said his agency’s sampling is stepped up when there are algal blooms in either Louisiana or Alabama.

“We are seeing Dinophysis in some of our samples, but not at the levels associated with a bloom. It’s something we find from time to time,” Gordon said. “We’re watching for it, but so far it is not an issue on the Mississippi reefs.”

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Raw Deal: Is protecting consumers from uncooked oysters a rotten plan?

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Raw oyster being taken from shell

Alejandro Linares Garcia (GNU Free)

Due to multiple accounts of people getting sick with stomach viruses over the last couple of weeks, several areas where oyster beds are located in Louisiana have been closed.

The Louisiana Department of Health and Hospitals have confirmed 38 cases of illnesses in Louisiana and Mississippi from eating raw oysters, including the Norovirus and vibrio vulnificus, a disease that prompted the Federal Food and Drug Administration to consider placing restrictions on eating raw oysters last year.  The oysters causing the sicknesses were traced to several parishes in Louisiana.

Oyster beds have been closed in Plaquemines, and St. Bernard parishes and parts of Lafourche and Jefferson parishes.  This is the largest closure of oyster bed fields in the past ten years in the state of Louisiana.

Symptoms of the Norovirus are nausea, vomiting, fever, chills and aches similar to the flu that will last up to two days.  The Norovirus is very contagious and can be passed on from person to person.

DHH has not found the actual cause of the contamination yet.  It could be from someone processing the raw oysters after harvesting or from contaminated waters.  So far tests in the water in suspected areas have all turned out negative.

The last outbreaks of the Norovirus occurred during the winter months in the 1990′s.

For more information on the oyster bed closures visit http://www.dhh.louisiana.gov/news.asp?ID=1&Detail=1597

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I’ve suspected that the first person to eat a raw oyster was either too drunk to know what they were doing or a freshman college student responding to an pledge challenge (and probably too drunk to know what they were doing).

There are two microbiologic reason to not eat oysters.

1: Oysters syphon seawater. So organisms that normally inhabit seawater are collected by oysters and live within them. The salt-loving (halophilic) bacteria can cause human illness, especially in those humans with iron storage problems (those with alcoholic liver disease). I personally saw a man die after eating a raw oyster at a local restaurant and after he developed shock from the microbe, Vibrio vulnificus. It was memorable to say the least.

2: Oysters syphon seawater. So any microbiologic that aren’t native to seawater but are contaminants in the water will concentrate in the oysters. That means that any fecal contamination of seawater by runoff from land will end up in the oysters. Hence historical concerns about hepatitis viruses (which are carried in human waste into the estuaries and then end up in oysters) are valid. Knowing that cycle (of human to waste to water to oyster) this weekend’s announcement by the US Food and Drug Administration of an outbreak of norovirus (Norwalk agent) contaminating oysters should be of no surprise. (Public Health Agencies Collaborate to Prevent Further Illnesses from Norovirus Outbreak Associated with Oysters Recently Harvested from Area Near Port Sulphur, La.)

Hot sauce doesn’t inactivate bacteria. Sprinkling tabasco sauce on oysters just makes the bacteria taste spicy.

Raw oysters don’t improve sexual powers. If that’s your motive, take a viagra.

The next burning question is “can you eat cooked oysters”?

Yeah, those are probably okay. Nutritionally I still don’t think they are a great idea.

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By Steven Hedlund, SeafoodSource editor
3/26/2010 8:48:23 AM – The U.S. Food and Drug Administration is looking at extending its plan requiring post-harvest processing on raw oysters to include all raw shellfish from the East and West coasts, according to Save Our Shellfish.

On Thursday, the organization, which represents numerous shellfish processors, growers and associations, released a statement claiming the FDA is moving forward with its plan requiring post-harvest processing on raw oysters even though the Interstate Shellfish Sanitation Conference (ISSC) at its meeting in Denver earlier this month again refused to endorse the plan.

The plan, which would effectively ban the sale of raw oysters for several months a year, is designed to protect Americans who suffer from gastrointestinal illnesses and can potentially die from consuming raw oysters tainted with the Vibrio bacterium.

“The FDA appears to be intent on regulating all raw shellfish just to protect a small group of susceptible people,” said Bob Rheault, director of the East Coast Shellfish Growers Association and a member of Save Our Shellfish. “These immune-compromised individuals should not be eating any raw foods.”

Now the FDA is considering extending its plan to include all raw shellfish, including raw clams, from the East and West coasts, said Save Our Shellfish, citing FDA memos.

In a 15 March letter to the U.S. Government Accountability Office, a bipartisan group of six senators and 12 congressmen, including Louisiana Sens. Mary Landrieu and David Vitter and Mississippi Sens. Thad Cochran and Roger Wicker, asked the agency to also conduct an audit of the FDA’s plan when it audits the ISSC’s Vibrio vulnificus risk management plan. The legislators are concerned that the FDA is not performing a thorough cost-benefit analysis of its plan.

In November, Landrieu, Vitter and other legislators spoke out against the plan on behalf of the Gulf Coast oyster industry. The FDA responded that it would engage with the industry, legislators and the ISSC but did not back off its plan, which is modeled after a California initiative enacted in 2003.

The U.S. oyster industry produces roughly 750 million pounds of in-shell oysters annually, two-thirds of which is produced by the Gulf Coast. Oysters from the warm-water region are known to carry the naturally occurring bacterium Vibrio vulnificus.

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(Logo: http://www.newscom.com/cgi-bin/prnh/20090824/FDALOGO )

Public health agencies are warning consumers not to purchase or eat oysters from the affected area and warning retailers and food-service operators not to sell or serve them. Louisiana’s Area 7 is in the Gulf of Mexico near the mouth of the Mississippi River.

The FDA was notified by state authorities that nearly a dozen consumers in Mississippi fell ill with norovirus after eating raw oysters from the affected area on March 10. Norovirus is a foodborne pathogen that can cause acute gastroenteritis in humans.

The Louisiana Department of Health and Hospitals has recalled oysters harvested from Area 7 on March 6 through March 24, 2010. State health officials closed the area to harvesting on March 24 to protect the public health.

Public health officials are currently working to investigate potential sources of pollution that may have caused the area to become contaminated.

Consumers who are uncertain about the origin of oysters they have in their possession should contact the place of purchase to determine if the oysters are from the affected area. Retailers and food service operators can check the tag or labeling that should accompany all raw molluscan shellfish to verify their origin.

Eleven people reported becoming sick after eating raw oysters at a conference center in Jackson County, Miss. Test results by the Mississippi State Department of Health confirmed that the patients were infected with norovirus.

Symptoms of norovirus illness usually include nausea, vomiting, diarrhea, and some stomach cramping. Sometimes people also have a low-grade fever, chills, headache, muscle aches, and a general sense of tiredness. The illness often begins suddenly, and the infected person may feel very sick. In most people the illness is self-limiting with symptoms lasting for one or two days.

People who have eaten raw oysters harvested from the affected area during the specified dates and have had symptoms of norovirus infection are encouraged to contact their health care professionals and local health departments.

People with weak immune systems, including those affected by AIDS, chronic alcohol abuse, liver, stomach or blood disorders, cancer, diabetes, or kidney disease and those taking certain medications for rheumatoid arthritis or cancer chemotherapy, should avoid raw oyster consumption altogether, regardless of where the oysters are harvested.

For more information on seafood safety, please visit www.cfsan.fda.gov/seafood1.html or call FDA’s Food Safety Hotline at 1-888-SAFEFOOD.

For information on Norovirus, go to: http://www.foodsafety.gov/poisoning/causes/bacteriaviruses/norovirus.html

For additional information on seafood, go to: http://www.foodsafety.gov/keep/types/seafood/index.html

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March 25, 2010, 4:53PM

The Louisiana Department of Health and Hospitals today ordered the closure of molluscan shellfish harvesting Area 3 in St. Bernard Parish. The closure takes effect at sunset.

Virus suspected in raw oysters harvested from area in St. Bernard ParishState Health Officer Jimmy Guidry signed the closure order when the department was notified of a possible Norovirus outbreak in New Orleans. Several people became ill over the weekend after eating raw oysters harvested from Area 3.  DHH is investigating to determine whether the oysters are to blame for the outbreak.

Norovirus is a virus that causes the “stomach flu.” Effects of the virus usually begin 24 to 48 hours after exposure. Symptoms, which last for one to two days on average, can include nausea, vomiting, diarrhea and stomach cramping. Occasional symptoms may include low-grade fever, chills, headache, muscle aches and tiredness. Norovirus can be contracted several ways, including by eating food or drinking liquids contaminated by infected food handlers. Outbreaks have occurred from eating undercooked oysters harvested from contaminated waters — cooking kills the virus.

DHH has notified local oyster harvesters that work in the affected areas, as well as the Louisiana Oyster Task Force, and the Louisiana Department of Wildlife and Fisheries.

The Louisiana Department of Health and Hospitals strives to protect and promote health statewide and to ensure access to medical, preventive and rehabilitative services for all state citizens.

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The Louisiana state Department of Health and Hospitals has closed a large section of east bank Plaquemines Parish waters to oyster fishing through at least mid-April, after 11 people in Mississippi – at a seafood conference, repeat, at a seafood conference — became sick after eating oysters believed to be traced to that area.

The Times-Picayune reports the state has also issued a recall of any oysters harvested from that area since March 6, meaning wholesalers must review their records and contact any restaurants, brokers or other buyers who bought oysters from those waters. Under Food and Drug Administration and state health guidelines, oyster dealers are required to have a recall plan in effect.

Updated: March 25, 2010 2:20 AM
Source: Associated Press

An outbreak of illnesses in Mississippi two weeks ago prompted a recall Wednesday of oysters harvested in Louisiana.

The Louisiana Department of Health and Hospitals says 11 people got sick with norovirus at a seafood conference.  One person was hospitalized but has since been released.

The recall affects oysters harvested since March 6 from Basin 4, Area 7 in Plaquemines Parish.  It applies to shucked, frozen, breaded and post-harvest processes oysters, as well as those for the half-shell market.

Cooking kills norovirus, but undercooked oysters can still carry it.

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