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Can an infectious and deadly prion disease of deer and elk jump species and infect humans?

New research by the indicates that’s a real likelihood.

“Our new data show that there is the potential for chronic wasting disease (CWD) to infect people,” says Dr. Hermann Schaetzl, MD, PhD, professor of prion biology and immunology and associate dean, research at UCVM. “Whether it already has happened, there's no data, but the more CWD prions you have out there in the environment, the higher the risk that human infections will occur in the future.

Disease rapidly spreading

And there’s a lot of CWD in the environment.  It’s killing deer in Alberta and Saskatchewan and rapidly spreading north, putting already endangered woodland caribou at greater risk. Westward expansion into the Rocky Mountains endangers elk, deer, moose and woodland caribou in Banff and Jasper National Parks.

“CWD is really exploding. In the last year, as many new cases were detected in one hunting season as in the previous 15 years altogether.” says Dr. Sabine Gilch, PhD, associate professor at UCVM and Canada Research Chair in Prion Disease Research. CWD can remain active in carcasses, saliva, and feces of infected animals and elsewhere in the environment for many years, leading to further infection of animals.

CWD is one of a group of infectious illnesses called prion diseases. One of the best-known prion diseases is bovine spongiform encephalopathy (BSE), or mad cow disease. They occur when normal prion proteins, found on the surface of many cells, become abnormal and clump in the brain, causing brain damage and eventually death.

Findings suggest risk to humans

“Prion diseases are known in humans. Previous studies have indicated the probability of CWD to transmit to humans to be very low, but now we have generated newer data in a study where CWD was transmitted to Macaque monkeys. Macaques are very similar to humans, they're currently the best model for testing zoonotic potential of prions,” says Gilch.

These new findings confirming people might be at risk of CWD make another UCVM research project evaluating an oral CWD vaccination strategy more crucial than ever.

“Work with the vaccine is going really well,” says Schaetzl. “We’re collaborating with a few groups including University of Alberta, Colorado State University and VIDO (Vaccine and Infectious Disease Organization at the University of Saskatchewan) and we have different approaches that are looking good in our animal models.”

The vaccine doesn’t prevent the disease, but it delays its onset.  Which is a significant factor in reducing the rapid spread of CWD.

“There's a pretty concerted research and funding effort now. And we're not putting our money on one vaccine, it's two or three vaccines and we have to produce them in an amount, in a packaging form, which allows us to do this oral vaccination in the wildlife,” says Schaetzl. “Three years ago, there was less support for the vaccination strategy, but that’s changed with COVID. Everybody's so much more in favor of vaccines now. We’re still a few years away and the vaccine will not be 100 percent effective, but it will do the job over time.”