Raw-fish buyer got rare bellyful of worms
Sushi lovers, beware: stomach-burrowing parasites may bite if you try to make the Japanese delicacy at home.
An Alberta man had the misfortune of hosting the first-recorded Canadian case of a nasty parasitic worm from raw fish he bought at a grocery store.
Doctors at Calgary’s South Health Campus were stumped when a 50-year-old man showed up in the emergency room in August 2014 in extreme pain with perpetual vomiting, doctors report in a paper published last month.
“This is such a rare, unusual etiology, I don’t think most people would put it too high on their list,” said Dr. Stephen Vaughan, an infectious diseases consultant with a special interest in tropical medicine.
An X-ray and CT scan showed irregularities in the man’s stomach just hours after he made himself sushi at home with raw wild salmon he bought at a Calgary Superstore.
When a gastrointestinal specialist sent a little camera down his throat into his stomach, what he found was the stuff of squeamish people’s nightmares.
Worms, about a centimetre long, were chomping their way through the man’s stomach lining. Doctors plucked a few of the larva out using endoscopic forceps, Vaughan said.
A microbiologist identified the worms as anisakis, which, on rare occasions, infect people who eat raw or undercooked seafood, the doctors report in the Canadian Journal of Infectious Diseases and Medical Microbiology.
In a shudder-worthy description, the U.S. Centres for Disease Control and Prevention says some diners feel a tingle in their mouth and throat when they unknowingly eat the worms.
Alberta has rules governing how restaurants must prepare sushi to prevent these kinds of infections, Vaughan said. Raw fish must be frozen below -20 C for at least a week or flash frozen below -35 C for at least 15 hours.
We have extremely rigorous policies and procedures to ensure the safety of the food in our stores.
An experienced sushi chef can sometimes see the creepy critters inside raw fish as they chop open the animals, he said.
Loblaws, which owns Superstore, was unaware of the worms incident, company spokeswoman Catherine Thomas said in an email.
“We have extremely rigorous policies and procedures to ensure the safety of the food in our stores. We do not market any of our fish for raw consumption,” Thomas said.
Raw farm-fed salmon and saltwater fish such as tuna are generally safe to eat, Vaughan said. However, the possibility of other parasites and bacteria in seafood prompts the paper’s authors to warn doctors to tell their patients to avoid eating raw fish at home.
The treatment of choice is to pluck the worms out of the patient’s stomach, both to help stop the symptoms and to identify the culprit. Left untreated, pain could last for weeks, and the worms could poke a hole in the stomach, leading to dangerous complications, Vaughan said.
“As more and more people eat sushi at restaurants, they’re going to be inclined to make sushi at home. If that’s the case, we’ll probably see more cases of this,” Vaughan said.