Can Chronic Wasting Disease (CWD) be transmitted to humans if cut with a knife used for butchering an infected deer?

Risk of CWD Transmission Through Contaminated Butchering Knife

There is currently no documented evidence of Chronic Wasting Disease (CWD) transmission to humans through any route, including contaminated knives used for butchering infected deer, though theoretical risk exists and precautionary measures are strongly recommended. 1, 2

Current Evidence on Human Transmission

• No cases of human prion disease caused by CWD have ever been recorded despite decades of potential exposure in endemic areas 1
• Most experimental data suggest the zoonotic risk of CWD is very low, indicating a strong species barrier between cervids and humans 1, 2
• However, the understanding of prion diseases remains incomplete regarding origin, transmission properties, and ecology 1

Known Routes of CWD Infectivity

• Prion infectivity has been definitively demonstrated in skeletal muscle of CWD-infected deer, meaning humans consuming or handling meat from infected animals are at risk for prion exposure 3
• CWD prions are present in saliva, feces, urine, and environmental reservoirs (soil and water) of infected cervids 4
• Pregnancy-related prion infectivity suggests potential mother-to-offspring transmission in cervids 4

Theoretical Risk from Knife Contamination

• While no specific studies address knife transmission, prions are extraordinarily resistant to standard decontamination methods
• Given that infectious prions exist in muscle tissue 3, a knife contaminated with tissue, blood, or bodily fluids from an infected deer could theoretically harbor prions
• Direct contact with infected animal materials represents a potential source of infection 4

Critical Concerns Warranting Precaution

• CWD prevalence is escalating in endemic areas, now affecting 30 U.S. states and four Canadian provinces, increasing human exposure risk 1
• The emergence of different CWD strains is concerning, as different strains have varying abilities to cross species barriers 2
• If CWD were to adapt to humans, clinical presentation would be unclear, making early detection difficult 2
• The precedent of bovine spongiform encephalopathy (BSE) causing variant Creutzfeldt-Jakob disease (vCJD) in humans demonstrates that animal prions can cross species barriers 1, 2

Recommended Precautionary Measures

• Implement protective measures to minimize human exposure to CWD prions, even in the absence of confirmed human cases 1
• Avoid consuming meat from deer harvested in CWD-endemic areas or from animals showing signs of illness 5
• Use dedicated equipment for processing potentially infected animals and avoid cross-contamination with knives or other tools 5
• Practice meticulous hand hygiene after handling potentially infected animals or equipment 6, 7
• Consider wearing gloves when field dressing or butchering deer from endemic areas

Key Clinical Pitfall

The absence of documented human CWD cases should not be interpreted as proof of safety—the incubation period for prion diseases can span decades, and systematic surveillance for atypical CJD strains potentially linked to CWD is limited 2. The best approach is thorough strain-typing of both harvested cervids and human CJD cases to detect any emerging transmission patterns 2.