Chronic wasting disease research shows potential for human infection
New research into chronic wasting disease (CWD) by a team from the University of Calgary shows it has the potential to cross the species barrier from deer to humans.
CWD is caused by prions — a form of misshapen protein that can trigger the fatal degenerative neurological condition.
“We show that there is some potential of CWD prions to cross the barrier to humans,” said Dr. Sabine Gilch, an associate professor at U of C's faculty of veterinary medicine and the Canada research chair in prion diseases.
“We cannot predict that it happens (in the real world), but the potential is there.”
Albertans consumed the meat of roughly 70,000 deer last year.
Click for more info: 2021 provincial CWD testing report
Of 10,909 cervids (deer, elk and moose) tested by the province, 1,156 tested positive for the disease.
The large majority of those were Mule deer. Eight were elk. No moose tested positive.
The peer-reviewed research paper was recently published in the journal Acta Neuropathologica. Lead author Samia Hannaoui was in Germany this week presenting the findings at a prion disease conference.
Using transgenic humanized mice, which mimic the response of human bodies, researchers injected CWD prions directly into the brains of the mice.
“The majority of those mice developed a clinical prion disease, so they got sick from this injection,” Gilch said.
Click for more info: The research paper from the University of Calgary
But there were further surprises, some of which are encouraging.
It took the infected mice two to three times longer to develop symptoms.
“Even though there is potential to transmit to humans, the barrier is really high. So it’s not a very efficient process, I would say,” Gilch said.
The peer-reviewed research did not look at whether mice could be infected under real-world conditions, where an unknown critical load of prions would have to be ingested and pass through the digestive tract and on to the brain.
There were two concerning findings as well.
“Despite the clinical disease, it was very difficult to confirm the disease with the diagnostic tests that are currently used for diagnosing prion diseases in humans,” Gilch said, adding that doctors examining patients with an apparent prion disease will need to not only test for CWD specifically, but may need to use improved testing procedures.
CWD has never been detected in humans, but the findings suggest that may be a function of long periods before symptoms appear, inadequate testing and the difficulty in triggering an infection under real-world conditions.
Click for more info: Data on the dose required to trigger infection
The final surprise was the presence of infectious prions in the mouse faeces.
"This is really something that has not been shown before for any human prion disease and also not for this specific mouse model, and it's something that really concerns us,” Gilch said.
The finding is significant because it shows that human-to-human spread would be possible, although modern hygiene may make that highly unlikely.
For people who may eat wild venison, the research doesn't change handling or consumption recommendations — have cervids tested for CWD, label meat, avoid handling brain or spinal tissue and don't eat meat from an infected animal.
While the law generally requires all edible portions of hunted animals to be eaten, CWD-positive animals are explicitly exempt.
CTVNews.ca Top Stories
DEVELOPING Live updates as Stormy Daniels testifies at Trump hush money trial
Adult film star Stormy Daniels will take the stand a second time Thursday as former U.S. president Donald Trump’s hush money case continues in Manhattan. Follow live updates here.
NEW Why these immigrants to Canada say they're thinking about leaving, or have already moved on
For some immigrants, their dreams of permanently settling in Canada have taken an unexpected twist.
Here are the ultraprocessed foods you most need to avoid, according to a 30-year study
Studies have shown that ultraprocessed foods can have a detrimental impact on health. But 30 years of research show they don’t all have the same impact.
NEW Capital gains tax change 'shortsighted' and 'sows division' business groups tell Freeland
Forging ahead with increasing Canada's capital gains inclusion rate 'sows division,' and is a 'shortsighted' way to improve the deficit, business groups are warning Finance Minister Chrystia Freeland.
Ontario man frustrated after $3,500 paving job leaves driveway in shambles
An Ontario man considering having his driveway paved received a quote from a company for $7,000, but then, another paver in the neighbourhood knocked on his door and offered half that rate.
RateMDs violates privacy of health professionals, class-action lawsuit claims
A lawsuit against RateMDs has been given the go-ahead by a B.C. Supreme Court judge who found the claim that the website violates the privacy rights of medical professionals is not 'bound to fail.'
Defence attacks Stormy Daniels' credibility as she returns to the stand in Trump's hush money trial
Stormy Daniels will return to the witness stand Thursday in Donald Trump's hush money trial as the defence tries to undermine the credibility of the porn actor's salacious testimony about their alleged sexual encounter and the money she was paid to keep quiet.
With contactless screening tech, this Toronto startup hopes to catch breast cancer early — and save lives
Amid evidence of rising breast cancer rates among young women in Canada, one Toronto startup is offering a contactless and radiation-free device that can help doctors identify suspicious changes in breast tissue. The company, Linda Lifetech, says this can lead to earlier detection of breast cancer.
Tornadoes tear through southeastern U.S. as storms leave 3 dead
Forecasters warned a wave of dangerous storms in the U.S. could wash over parts of the South early Thursday, a day after severe weather with damaging tornadoes and large hail killed at least three people in the region.