VIBRIO PARAHAEMOLYTICUS, OYSTERS - USA: (MASSACHUSETTS)
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Date: Thu 10 May 2012
Source: Cape Cod Times [edited]
<http://www.capecodonline.com/apps/pbcs.dll/article?AID=/20120510/NEWS/205100330>
Scientists have always warned there would be a price to pay for global warming and 5 people in 2011 paid heavily. State health and fishery officials told shellfishermen and dealers at a meeting Wednesday night, 9 May 2012, that warming ocean waters in the eastern part of Cape Cod Bay have created a more favorable environment for the _Vibrio parahaemolyticus_ bacterium, both increasing its population size and lengthening its growing season.
The result was that, for the 1st time, the Massachusetts Department of Public Health confirmed that 5 people had fallen ill over the summer and fall of 2011 after eating raw oysters that were contaminated with the bacterium. "This wasn't 5 people getting diarrhea. These people were quite ill, and one came close to death," said Suzanne Condon, associate commissioner at the state Department of Public Health. The bacteria causes diarrhea, cramping, nausea, vomiting and fever. It can also cause bloodstream infections. Eating raw oysters is the most common way to contract it.
After the 1st 2 reported illnesses, which occurred last July 2011 at restaurants in Dennis, the FDA ordered the state DPH and Division of Marine Fisheries to come up with a plan before the summer to protect the public from June to September. The other 3 confirmed cases were from oysters eaten at the Wellfleet OysterFest in the fall of 2011.
_Vibrio parahaemolyticus_ is a naturally occurring bacterium that likes warmer waters and multiplies rapidly in temperatures above 80 degrees. While Massachusetts average water temperatures are cooler than that, much of the harvesting on Cape Cod Bay in the summer is done on tidal flats where oysters can be exposed to the sun for hours.
Plus it can take hours to gather and transport them to the dealer or customers. That gives the bacteria an opportunity to multiply, health officials said.
Martin Dowgert, the FDA Northeast Region shellfish specialist, told the audience that scientific studies had determined that refrigerating or icing oysters within the 1st 5 hours after they had either been exposed by the tide or been harvested, with a goal of chilling it enough to lower the oysters' temperature to 50 degrees within 10 hours would stem the exponential growth of the bacteria and keep them at safe levels to be consumed.
State officials are holding 2 meetings to ask shellfishermen and dealers how to best protect the public while allowing them to continue harvesting oysters for the raw market in the summer months. "This is not optional," said Mike Hickey, DMF's chief shellfish biologist. What is optional, he added, was their ideas on how to keep oysters cool while working in the hot summer sun. Everyone could name the problems:
People couldn't afford refrigerated trucks, dealers weren't open for evening tides, the harvesting process sometimes takes longer than 5 hours. But the bottom line, Hickey said, is finding solutions that could avoid having to close down the fishery in the warm months, or requiring expensive decontamination procedures, or ending the raw oyster market in the summer by only allowing them to be sold for cooking. Much of the rest of the country has such a plan in place because the outbreaks have been more frequent and much more severe.
This past week [?week of 7 May 2012], Louisiana had 14 cases of Vibrio sickness, said Michael Moore, director of the DPH Food Protection Program.
New York state and the West Coast have had cases where 100 people at a time fell sick. "If 2 cases came across my desk in July, I'd have to do a recall," Moore said, pulling back all raw oysters from dealers and restaurants that came from the area where the contaminated shellfish were harvested.
Shellfish, both grown in pens or racks in aquaculture operations, or harvested from the wild, employs thousands and is worth hundreds of millions of dollars, Condon said.
[Byline: Doug Fraser]
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[It is important to stress that _Vibrio parahaemolyticus_ is naturally present in marine waters and does not imply sewage contamination, as would be the case with _Salmonella_ sp. or _E. coli_. It is most common in warmer waters such as those of the American Gulf Coast, but warmer waters in more northern climates can also be associated with oyster-associated _V. parahaemolyticus_.
In 2005, a New England Journal of Medicine report highlighted this infection linked to even Alaskan oysters:
McLaughlin, JB, DePaola A, Bopp CA, et al: Outbreak of _Vibrio parahaemolyticus_ Gastroenteritis Associated with Alaskan Oysters. N Engl J Med 2005; 353: 1463-70 (full article available at <http://www.nejm.org/doi/full/10.1056/NEJMoa051594>).
"Abstract
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Background: _Vibrio parahaemolyticus_, the leading cause of seafood-associated gastroenteritis in the USA, typically is associated with the consumption of raw oysters gathered from warm water estuaries. We describe a recognized outbreak of _V. parahaemolyticus_ infection associated with the consumption of seafood from Alaska.
Methods: After we received reports of the occurrence of gastroenteritis on a cruise ship, we conducted a retrospective cohort study among passengers, as well as active surveillance throughout Alaska to identify additional cases, and an environmental study to identify sources of _V. parahaemolyticus_ and contributors to the outbreak.
Results: Of 189 passengers, 132 (70 percent) were interviewed; 22 of the interviewees (17 percent) met our case definition of gastroenteritis. In our multiple logistic-regression analysis, consumption of raw oysters was the only significant predictor of illness; the attack rate among people who consumed oysters was 29 percent. Active surveillance identified a total of 62 patients with gastroenteritis. _V. parahaemolyticus_ serotype O6:K18 was isolated from the majority of patients tested and from environmental samples of oysters. Patterns on pulsed-field gel electrophoresis were highly related across clinical and oyster isolates. All oysters associated with the outbreak were harvested when mean daily water temperatures exceeded 15.0 C (59 F) (the theorized threshold for the risk of _V.
parahaemolyticus_ illness from the consumption of raw oysters). Since 1997, mean water temperatures in July and August at the implicated oyster farm increased 0.21 C per year (P less than 0.001 by linear regression); 2004 was the only year during which mean daily temperatures in July and August 2004 at the shellfish farm did not drop below 15.0 C (59 F).
Conclusions: This investigation extends by 1000 km (621 miles) the northernmost documented source of oysters that caused illness due to _V. parahaemolyticus_. Rising temperatures of ocean water seem to have contributed to one of the largest known outbreaks of _V.
parahaemolyticus_ in the USA." - Mod.LL
A HealthMap/ProMED-mail map can be accessed at:
<http://healthmap.org/r/1Lkk>.]
[see also:
2011
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Vibrio parahaemolyticus, oysters - USA (04): (WA) expanded alert
20110927.2924
Vibrio parahaemolyticus, oysters - USA (03): (WA) alert 20110915.2820 Vibrio parahaemolyticus, oysters - USA (02): (CA) 20110913.2786 Vibrio parahaemolyticus, oysters - USA: (WA) 20110807.2394 2010
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Vibrio parahaemolyticus, oysters - USA: (WA) 20100803.2604
2008
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Vibrio parahaemolyticus, seafood - Chile 20081223.4041 Vibrio parahaemolyticus, oysters - USA: (MD ex NJ) 20080821.2608
2007
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Vibrio parahaemolyticus, oysters - USA (WA): int'l alert
20070813.2637
Vibrio parahaemolyticus, shellfish - Chile: 2005 20070321.0991 Vibrio parahaemolyticus, shellfish - Chile (San Antonio)
20070202.0422
2006
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Vibrio parahaemolyticus, shellfish - USA (multistate) (03)
20060821.2347
Vibrio parahaemolyticus, shellfish - USA (multistate) 20060807.2211 Vibrio parahaemolyticus, shellfish - USA (WA, NY) (05) 20060805.2175 Vibrio parahaemolyticus, shellfish - USA (WA, NY) 20060721.1999 Vibrio parahaemolyticus - North America: background 20060717.1963 Vibrio parahaemolyticus, oysters - North America: USA (OR, WA), Canada
(BC) 20060716.1956
2005
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Vibrio parahaemolyticus, seafood - Chile (Puerto Montt) (03)
20050223.0578
Vibrio parahaemolyticus, seafood - Chile (Puerto Montt) 20050118.0163
2004
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Food poisoning, birthday guests - USA (FL) (02): vibrio parahaemolyticus 20040927.2664 Food poisoning, birthday guests - USA (FL) 20040922.2619 Vibrio parahaemolyticus, oysters - USA (AK) (02) 20040822.2335 Vibrio parahaemolyticus, oysters - USA (AK) 20040803.2113
2002
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Vibrio parahaemolyticus, shellfish - USA (NY): alert 20020822.5111 Vibrio parahaemolyticus, O3:K6 - USA, Asia 20020716.4770 2000
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Vibrio parahaemolyticus, oysters - USA (Texas) 20000928.1676
1999
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Vibrio parahaemolyticus, oysters - USA (multistate) 19990725.1252] .................................................ll/mpp
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