Chronic wasting disease (CWD) is a prion disease affecting cervids (deer, elk, moose etc.), first detected in the 1960s. Since then, CWD has been identified in 35 different US states and 5 Canadian provinces. This fatal disease has spread aggressively in wild cervid populations, in part due to its ability to cause long-term infectious contamination in soil, plants and water sources. Of immediate concern, is the potential for CWD to enter threatened caribou populations and the rapid decline of deer populations in endemic areas. Vaccination is the most effective tool for control of infectious diseases in animals and humans. While the development of a prion vaccine is challenging, significant work has been conducted by researchers at the Vaccine and Infectious Disease Organization (VIDO), resulting in a promising vaccine reaching  efficacy trials.

The likely vaccine candidate is an oral vaccine meant to be eaten, like that of the established oral rabies vaccines; however, the rigid blister pack utilized for wildlife rabies vaccines is incompatible with the eating habits of cervids, who are unlikely to chew through the hard plastic packaging material. As deer baiting is common through many areas affected by CWD, methods of deploying the vaccine to reach the largest number of deer in the shortest timeframe are expected to include delivery of the vaccine at bait stations throughout the affected regions. Therefore, we are exploring what different baits would be compatible with the possible methods of “packaging” the vaccine to maximize uptake.

The two vaccine “packaging” methods being investigated by VIDO are liquid-filled “boba/milk tea” balls, and a thin dry film (like a Listerine strip). The liquid “boba” method requires the balls staying wet from being placed at a bait station to when the bait is eaten while the “Listerine” strip method requires the strip staying dry until being eaten. VIDO has partnered with OHMT to research what method is optimal in terms of deer feeding. 

This research and development project will include testing deer feeding preferences followed by engineering of a delivery solution to solve any identified issues, such as environmental control for maintenance of vaccine stability at delivery sites, and ability to limit vaccine access to non-target species and return animals. 

Is CWD an issue you are passionate about? This project has multiple opportunities for citizen science and volunteer involvement. Learn more about our experimental plans for the Spring/Summer of 2025 here. Experimental Summary – CWD Vaccine Deployment 2025