Tag Archives: paralytic shellfish poison

With caution, one can avoid the risk of illness when gathering shellfish

If you are planning to gather some shellfish to eat over Labor Day weekend — or anytime for that matter — state health officials urge you to follow the “three Cs” of shellfish — check, chill and cook.

The state’s Shellfish Safety Map shows areas open and closed to harvesting.
Map: Washington State Dept. of Health

At least 10 cases of an intestinal illness called vibriosis have been reported this year to the Washington State Department of Health, all resulting from people picking oysters themselves and eating them raw or undercooked. The disease is caused by a bacteria, Vibrio parahaemolyticus, an organism that occurs naturally and thrives in warm temperatures.

“The shellfish industry follows special control measures during the summer months to keep people who choose to eat raw oysters from getting sick,” said Rick Porso, director of the Office of Environmental Health and Safety, in a news release. “For those who enjoy collecting and consuming their own shellfish, it’s important that they follow a few simple measures to stay healthy.”

The combination of warm weather, lack of rain and low tides all contribute to the growth of bacteria in oysters growing on the beach.

The state Department of Health uses the “three Cs” as a reminder for recreational shellfish harvesters as well as people who gather shellfish from their own beaches:

  • CHECK: Before heading to the beach, make sure that shellfish in the area are safe to eat. The Shellfish Safety Map, updated daily, will tell you where it is safe to gather shellfish. At the moment, many areas are closed because of paralytic shellfish poison produced by a type of plankton. Unlike Vibrio, PSP cannot be destroyed by cooking.
  • CHILL: Gather shellfish as the tide goes out, so they are not allowed to sit for long in the sun. Put them on ice immediately or get them into a refrigerator.
  • COOK: Cooking at 145 degrees F. for at least 15 seconds should destroy Vibrio bacteria, health officials say. It is not enough to cook them until their shells open.

Symptoms of vibriosis include diarrhea, abdominal cramps, nausea, vomiting, headache, fever and chills. The illness usually runs its course in two to three days. For information see “Vibriosis” on the Department of Health’s website.

Symptoms of paralytic shellfish poisoning usually begin with tingling of the lips and tongue, progressing to numbness in fingers and toes followed by loss of control over arms and legs and difficulty breathing. Nausea and vomiting may occur. PSP can be a life-threatening condition, so victims should seek medical help immediately. For information, see “Paralytic shellfish poison” on the Department of Health’s website.

Besides health advisories, the Shellfish Safety Map mentioned above also includes the water-quality classification, a link to shellfish seasons to determine whether a beach is legally open along with other information,

Automated monitor provides early warning of harmful algae blooms

Automated equipment installed Monday off the Washington Coast will track concentrations of six species of plankton that could become harmful to humans and marine species.

The Environmental Sample Processor, or ESP, collects discrete samples of water and processes them for analysis. Imbedded modules can test for DNA and antibodies to identify the organisms picked up in the seawater. Concentrations of the plankton and their toxins are sent to shore-based researchers via satellite.

The equipment was installed by scientists with the National Oceanic and Atmospheric Administration and the University of Washington. The device was developed at the Monterey Bay Aquarium Research Institute. Stephanie Moore of NOAA’s Northwest Fisheries Science Center explains the benefits of the device in the first video on this page. The second video provides a few more technical details with graphic depictions of the device.

The ESP was deployed in the Juan de Fuca eddy, a known pathway for toxic algae 13 miles off the Washington Coast near LaPush. The remote, self-operating laboratory will operate about 50 feet underwater.

One of the primary targets of the monitoring is Pseudo-nitzschia, a harmful algae capable of producing domoic acid. This toxin can accumulate in shellfish and can cause diarrhetic shellfish poisoning, which can progress to severe illness. Last year, a massive bloom of this toxic algae canceled scheduled razor clam seasons on Washington beaches with untold economic consequences.

The harmful algal bloom (HAB) affected the entire West Coast, from California to Alaska. It was the largest and longest-lasting bloom in at least 15 years, according to NOAA’s National Ocean Service.

“Concentrations of domoic acid in seawater, some forage fish and crab samples were among the highest ever reported in this region,” says a factsheet from the service. “By mid-May, domoic acid concentrations in Monterey Bay, California, were 10 to 30 times the level that would be considered high for a normal Pseudo-nitzschia bloom.”

“Other HAB toxins were also detected on the West Coast. Shellfish closures in Puget Sound protected consumers from paralytic shellfish poisoning and diarrhetic shellfish poisoning.”

Paralytic shellfish poisoning is associated with a group of plankton called Alexandrium, typically Alexandrium catenella in the Puget Sound region.

In addition to sampling for Alexandrium and four species of Pseudo-nitzchia, the ESP is monitoring for Heterosigma akashiwo, which is associated with massive fish kills, including farmed salmon.

Anyone can track some of the data generated by the equipment by visiting NANOOS — the Northwest Association of Networked Ocean Observing Systems.

Early warning of toxic algal blooms can assist state and local health officials in their surveillance of toxic shellfish.

“Anyone can access the data in near-real-time,” UW oceanographer and NANOOS Director Jan Newton told Hannah Hickey of UW News and Information. “It’s an early warning sentry.”

Map points toward safe — and hazardous — shellfish

A highly informative map, just released by state shellfish officials, can show you at a glance where it is safe to harvest shellfish in Western Washington.

Shellfish_map

Besides pointing out the locations of public beaches where recreational harvesters may safely gather clams and oysters, the new map provides links to information about the approved seasons and limits, with photographs of each beach. One can choose “map” or “satellite” views, as well as enhanced images to simplify the search.

If you wish, you can track down locations by searching for the name of a beach, nearby landmarks or the address. You can obtain the latest information about entire shorelines as well as specific beaches.

The map was created by the Office of Shellfish and Water Protection, a division within the Washington State Department of Health.

Jim Zimny, recreational shellfish specialist at Kitsap Public Health District, said he expects the map to be updated immediately when new health advisories are issued.

“It’s a great resource, very easy to use,” Jim said.

Jim works with state shellfish officials to collect shellfish samples and report results, including findings of paralytic shellfish poison, a biotoxin. Closures are announced when high levels of PSP or dangerous bacteria are found. Hood Canal, for example, is covered with the letter “V,” meaning one should cook shellfish thoroughly to kill Vibrio bacteria, which can lead to intestinal illness.

Since I generally write the geographic descriptions of shellfish closure areas, I can assure you that looking at a map will be a better way to see what is going on.

A news release about the new map points out that the risk of eating shellfish increases in summer. That’s why it especially important in summer to follow the three C’s of shellfish safety: “check, chill and cook.”

Those three C’s refer to checking the map for health closures and looking on the beach for warning signs; chilling the shellfish to avoid a buildup of bacteria; and cooking to 145 degrees to kill pathogens. (Cooking does not destroy PSP and other biotoxins, so it’s important to avoid closed areas.)

For additional information about recreational shellfish harvesting, including a “Shellfish Harvest Checklist,” visit the Department of Health website.

China maintains ban on shellfish imports

Business and government officials involved in the lucrative geoduck export market got some bad news on Friday, when federal authorities released a letter they had received from the Chinese government.

Kitsap Sun photo
Kitsap Sun photo

The letter raises many questions — at least from a Chinese perspective — about how the U.S. regulatory system protects public health. The message from Chinese health authorities dashes the hopes of industry officials for a quick lifting of the Chinese ban on shellfish imports from the U.S. West Coast.

I wrote about this issue for Saturday’s Kitsap Sun (subscription). My story was picked up by the Associated Press and distributed widely. (If you don’t subscribe to the Sun, see The Columbian, Vancouver, for the AP version.)

Washington state has a proud reputation for protecting public health when it comes to shellfish, and the letter from China does little to dispel suspicions among those who think that China may have ulterior motives. After all, Chinese authorities have done nothing to limit the geographic scope of the import ban or even limit the ban to geoducks only.

A statement (PDF 114 kb) from the National Oceanic and Atmospheric Administration concludes that the letter contains about 20 separate requests for information about testing and safety.

You may wish to read the the letter from China’s General Administration of Quality Supervision, Inspection and Quarantine (PDF 150 kb). As translated, the letter includes this statement:

“We don’t not have a full understanding of the US regulatory system including the definition of sea region and management, the official monitoring on PSP and heavy metals and the responsibility among the relevant government agencies, and we have not conducted an on-site evaluation neither.”

The letter says the suspension of imports may be reduced to a specific area after certain questions are answered. It calls on the U.S. to develop an action plan for evaluation and outlines a review process, including a visit by an “expert team” from China to evaluate the geoduck inspection programs.

Officials at all levels in the U.S. say they are evaluating the questions posed in the letter and preparing a coordinated response.

Previous entries in Water Ways:

Jan. 9, 2014: Geoducks test OK, but what’s behind Chinese ban?

Dec. 24, 2013: Health officials to quickly test geoducks for arsenic