VIBRIO PARAHAEMOLYTICUS, OYSTERS - USA: (WASHINGTON STATE)
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Date: Fri 5 Aug 2011
Source: Examiner [edited]
<http://www.examiner.com/infectious-disease-in-national/washington-vibrio-parahaemolyticus-outbreak-linked-to-raw-oysters>
At least 22 people have become ill after eating raw oysters in Washington State according to a Thu 4 Aug 2011 Washington State Department of Health (WSDH) news release. The illnesses, caused by the bacterium _Vibrio parahaemolyticus_, have been connected to both raw oysters from commercial harvesting (18) and recreational harvesting (4).
The WSDH offers the following steps to avoid vibriosis:
- Put oysters on ice or refrigerate them as soon as possible after harvest.
- If a receding tide has exposed oysters for a long time, don't harvest them.
- Always cook oysters thoroughly. Cooking oysters at 145 F for 15 seconds destroys vibrio bacteria.
- Rinsing fully-cooked oysters with seawater can re-contaminate them.
- For commercial harvesters, special control measures are in place from May through September to keep people from getting sick if they eat raw oysters.
- Shellfish companies must quickly refrigerate oysters after they're harvested. They're required to keep detailed harvest and temperature control records to show that the oysters were handled properly.
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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]
[see also:
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] .................................................sb/ll/msp/dk
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