Posts Tagged ‘seafood’

Potentially deadly.

Potentially deadly.

Dungeness and rock crabs in California have been found to contain toxic levels of an acid that can kill.

The authorities in California are advising people to avoid consumption of crabs contaminated by a natural toxin that has spread throughout the marine ecosystem off the West Coast, killing sea mammals and poisoning various other species.

Kathi A. Lefebvre, the lead research biologist at the Wildlife Algal Toxin Research and Response Network, said on Wednesday that her organization had examined about 250 animals stranded on the West Coast and had found domoic acid, a toxic chemical produced by a species of algae, in 36 animals of several species.

“We’re seeing much higher contamination in the marine food web this year in this huge geographic expanse than in the past,” Ms. Lefebvre said.

She said that the toxin had never before been found in animals stranded in Washington or Oregon, and that there were most likely greater numbers of contaminated marine mammals not being found by humans.

The guilty algae’s growth has been exponential recently, largely because of record temperatures in the Pacific Ocean. Warm water causes the toxic algae to divide more rapidly and to outcompete other species in the water. The algae then becomes a more prominent element of local plankton, a kind of marine trail mix made up of tiny particles that various species of aquatic wildlife subsist on.

The California Department of Public Health recently advised people to avoid consumption of certain species of crabs because of potential toxicity. Razor clam fisheries in Washington have been closed throughout the summer for the same reason.

In a statement released on Tuesday, the California department said that “recent test results” indicated dangerous levels of domoic acid in Dungeness and rock crabs caught in California waters between Oregon and Santa Barbara, Calif.

Domoic acid is a naturally occurring toxin that in severe cases can cause excessive bronchial secretions, permanent loss of short-term memory, coma or death in humans, according to the California department’s statement. Milder cases can result in vomiting and diarrhea.

A release from the National Oceanic and Atmospheric Administration Fisheries specified that “commercial seafood remains safe and state public health agencies monitor recreational fisheries for algal toxins.”

Pseudo-nitzschia, the type of algae that produces the acid, is a single-celled organism consumed directly by marine wildlife like anchovies, sardines, krill and razor clams. Those species are then eaten by larger predators, and the acid makes its way up the marine food chain.

This summer, the West Coast experienced the largest algal bloom that scientists have on record. Ms. Lefebvre said that though there was not a lot of monitoring for species that had consumed domoic acid in Alaska, it was likely that the blooms reached the Alaskan coast as well.

Michael Parsons, a professor of marine science at Florida Gulf Coast University, said there were several hypotheses for why Pseudo-nitzschia produces acid.

“We’re not sure exactly why they do it,” he said. “Maybe it’s meant to keep things from eating them. It might be a result of stress.”

If acid secretion is meant to deter predators, it is clear that it is a failing strategy on the part of the algae. Ms. Lefebvre expressed concern that the acid poisoning of sea life would continue to spread.

“My concern is that we’re going to see an increase in the number and geographic range of marine mammals being affected,” she said.

Or in other words, global warming is killing the seas, and now it can kill you too. And that’s before we even return to the topic of ocean acidification and its affect on our food chain. Or how this news will affect commercial fishers, and restaurants.

But don’t worry, everyone, go back to sleep, go back to sleeeeeeep ….

(NY Times and others)

Seafood-buffet

 

Wellthisiswhatithink’s Mum used to scoff oysters with cheerful excess until one day she ate a bad one. She was so crook she never touched another one for the next thirty years till old age carried her off.

Well, oysters now appear to be an important link in the transmission of norovirus among humans, according to new research from China.

Norovirus — better known as “cruise-ship flu,” “stomach flu” or “winter vomiting flu” — is one of the world’s most common causes of gastrointestinal distress. Although most patients recover after a few days of misery, and sometimes ruined vacations, the virus can sadly be lethal to infants, older adults and people with weak immune systems.

It is highly infectious — especially in confined environments like ships — but exactly how it is transmitted has been a mystery.

The unwashed hands of food workers have been blamed. But recently, scientists at North Carolina State University built a “vomiting machine” that showed tiny infectious droplets of vomit can fly through the air to infect other people, just as droplets from a sneeze will do.

In the current study, published last month in Applied and Environmental Microbiology, researchers analyzed the genetic sequences of 1,077 samples of noroviruses found in oysters. Some sequences had been stockpiled in genetic databases since 1983.

The scientists found that 80 percent of the known human noroviruses matched those found in oysters. The majority of the matches were in oysters from coastal waters, more likely to be contaminated with human sewage.

Noroviruses mutate very quickly, as do influenza viruses, and big outbreaks usually begin after a new strain emerges. There was a “convergence” between new strains circulating in oysters and those circulating in humans, the researchers also found.

Yongjie Wang, a food science specialist at Shanghai Ocean University and lead author of the study, concluded that oysters were an important reservoir for human noroviruses — a place where they can hide between outbreaks and mutate. They also can be transmitted back to humans, presumably when oysters are eaten raw. A way to detect noroviruses in oyster flesh and in the beds where they grow needs to be developed, Dr. Wang said.

Alternatively, avoid enclosed spaces where people are vomiting, and go easy on the seafood buffet.

(NY Times)