Study by Calgary doctors warns home cooks about parasites in raw fish

Calgary doctors say a rare parasite could become more common as uncooked culinary trends such as sushi, sashimi and ceviche grow in popularity. A new report in the Canadian Journal of Infectious Diseases and Medical Microbiology examines the case of a Calgary man stricken by tiny parasitic worms in his stomach after eating raw, wild salmon from a grocery store.

Calgary doctors say a rare parasite could become more common as uncooked culinary trends such as sushi, sashimi and ceviche grow in popularity.

A new report in the Canadian Journal of Infectious Diseases and Medical Microbiology examines the case of a Calgary man stricken by tiny parasitic worms in his stomach after eating raw, wild salmon from a grocery store.

The article says it’s the first time the tiny, toothed worms have been found in a human after consuming Canadian store-bought salmon.

Dr. Stephen Vaughan from Calgary’s South Health Campus led the study and reported the results.

The report says the 50-year-old man arrived in the emergency department with vomiting and upper abdomen pain about one hour after eating raw, wild salmon.

After x-rays and stool tests found nothing remarkable, doctors sent an endoscope camera inside the patient’s stomach and spotted the worms — between one and two centimetres long — wriggling inside several stomach ulcers.

Two worms were removed and identified as anisakis, a parasitic worm that lives in fish and aquatic animals and leads to the condition anisakiasis.

“Although a skilled sushi chef will recognize the distinctive `watch coil’ appearance of the larval worms (approximately 1 centimetres to 2 centimetres) in raw fish, individuals preparing their own sushi may not,” the report’s authors wrote.

Researchers say that raw fish prepared at home can contain anisakis and other dangerous parasites because the fish may not have been frozen — a process typically used by sushi restaurants that kills the tiny larvae.

Several provinces have regulations that ensure that raw fish is frozen before being served at restaurants, but grocery stores are often not included in such regulations.

To err on the side of caution, the report recommends that fish purchased from grocery stores be frozen at -20 C for a week — or at a colder temperature for a shorter period of time — before being eaten raw.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

NDP leader Rachel Notley is calling on the UCP to make a public inquiry into the COVID-19 outbreak at Olymel. (Facebook screenshot)
Notley calls for Olymel inquiry as plant reopens

Union also asks for further consideration to delay opening

Protesters
UPDATE: Rally held outside Red Deer court for slain central Alberta man

Tyler John Campbell charged with second-degree murder for December 2019 homicide

(Contributed image).
Deadline extended for arts scholarship applications for Red Deer-area students

Red Deer Arts Council will accept applications until March 15

Hog slaughter operations resumed on Thursday at Red Deer’s Olymel plant, which was closed for two weeks to curb the spread of COVID-19 among workers. Three employee deaths resulted from the latest outbreak. (Advocate file photo).
Hog slaughtering operations gear up again at Red Deer’s Olymel plant

Workers begin to return after 14-day closure due to COVID-19 outbreak

Alberta’s Chief Medical Officer of Health Dr. Deena Hinshaw says the greater lag time between first and second doses will allow more Albertans to be effectively vaccinated sooner. (File photo)
Alberta extends time between vaccine doses means more people to get shot sooner

National Advisory Committee on Immunization says doses can be to up to four months apart

Bryson, six, and Mara, eight, play with puppies from Dogs With Wings Saturday. (Photo by Sean McIntosh/Advocate staff)
WATCH: Dogs With Wings introduces Red Deer program

A program that trains puppies to be certified service, autism, facility and… Continue reading

Unifor national president Jerry Dias speaks during a press conference in Toronto on Thursday, Oct. 15, 2020. Dias says Air Canada is pledging passenger refunds as negotiations over federal aid for airlines drag on. THE CANADIAN PRESS/Tijana Martin
Unifor’s Dias says Air Canada holding to refund pledge as aid negotiations drag on

OTTAWA — Unifor president Jerry Dias says Air Canada continues to promise… Continue reading

Lionel Desmond (front row, far right) was part of the 2nd battalion, of the Royal Canadian Regiment, based at CFB Gagetown and shown in this 2007 handout photo taken in Panjwai district in between patrol base Wilson and Masum Ghar in Afghanistan. THE CANADIAN PRESS/HO-Facebook-Trev Bungay MANDATORY CREDIT
Desmond inquiry: social worker reveals details about former soldier’s family life

PORT HAWKESBURY, N.S. — An inquiry in Nova Scotia is hearing testimony… Continue reading

Seniors arrive for their COVID-19 vaccination at a clinic in Olympic Stadium in Montreal on March 3, 2021. THE CANADIAN PRESS/Paul Chiasson
Nova Scotia eases COVID-19 restrictions; cases creep up in Ontario

Nova Scotia is easing public-health restrictions in and around Halifax, while new… Continue reading

Infrastructure and Communities Minister Catherine McKenna stands near a bus as she waits to start an announcement at a public transit garage in Ottawa, Thursday March 4, 2021. THE CANADIAN PRESS/Adrian Wyld
Liberals tap $2.5B of promised transit dollars for zero-emission buses

OTTAWA — The federal Liberals are setting aside some of the billions… Continue reading

Canada’s Eliot Grondin looks on after competing in a men’s snowboard cross heat at the Phoenix Snow Park at the 2018 Winter Olympic Games in Pyeongchang, South Korea, Thursday, Feb. 15, 2018. Grondin continued his strong season with his first career World Cup snowboard cross victory on Thursday. THE CANADIAN PRESS/Jonathan Hayward
Canadian Eliot Grondin captures gold at World Cup snowboard cross event

BAKURIANI, Georgia — Canada’s Eliot Grondin continued his strong season with his… Continue reading

FILE - In this Feb. 23, 2021, file photo, a vehicle rests on its side after a rollover accident involving golfer Tiger Woods in the Rancho Palos Verdes suburb of Los Angeles. Detectives are looking at data from the so-called “black box” of Tiger Woods’ SUV to get a clearer picture of what occurred during the Southern California rollover crash last week that seriously injured the golf star, authorities said Wednesday, March 3. (AP Photo/Marcio Jose Sanchez, File)
Detectives look at SUV’s ‘black box’ from Tiger Woods crash

California law allows law enforcement to seek search warrants for data recorders

Most Read