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Chronic wasting disease may transmit to humans, research finds

UCalgary vet med researchers publish first study showing risk to humans higher than previously thought
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Risk of transmission of chronic wasting disease exists, discover UCalgary researchers. Photo: Metro Creative Connection

Chronic wasting disease (CWD), a highly infectious and fatal neurological disease that’s spreading through North American herds of elk, moose, mule and white-tailed deer, may be more transmissible to humans than previously thought. Researchers in the University of Calgary Faculty of Veterinary Medicine (UCVM) have published a paper that shows there is a risk of transmission of the prion disease.

“This is the first study to show there is an actual risk that it can transmit to humans,” said Dr. Sabine Gilch, PhD, associate professor and Canada Research Chair in Prion Disease Research at UCVM. Prion diseases attack proteins in the brain, causing clumps to form and eventually, death.

Two well-known prion diseases are bovine spongiform encephalopathy (BSE), or Mad Cow Disease, in cattle and Creutzfeldt-Jakob disease in humans. “From Mad Cow Disease we know that prion diseases can jump the transmission barrier from animals to humans,” said Gilch. “BSE was transmitted through contaminated meat or food products to humans and caused a new form of human prion disease, called variant Creutzfeldt-Jakob disease.”

Previous research has studied hunters who consume game in geographies with high prevalence of the disease in animals and found no evidence of human infection. “This study is an experimental model, yet it gives a lot of new information and insight to the zoonotic potential of CWD if you compare it with other published studies,” said lead author Dr. Samia Hannaoui, PhD.

Hannaoui and colleagues took CWD isolates from infected deer and injected them into “humanized” mouse models. Over a period of years, the mice developed CWD. Further, the mice were found to shed infectious prions in feces.

“The implication is that CWD in humans might be contagious and transmit from person to person,” said Gilch.

“When we look at humans, we usually see a typical signature. And in this mouse model we did not find that signature, which means if this ever happens with humans, it will not look like the prion diseases that we know. It might be significantly different from whatever we know so far.”

Article courtesy of UCalgary