According to a new study by the U.S. Geological Survey (USGS) and the Wyoming Game and Fish Department, harvesting more bucks can curb the spread of chronic wasting disease (CWD).
The study’s authors looked at CWD trends in 10 different mule deer herds across central and eastern Wyoming with varying levels of hunting pressure. They analyzed data from 2000 to 2021 gathered by the Wyoming Game and Fish Department to determine if hunting pressure affected the spread of CWD. “We found that harvesting a high proportion of the adult males in the herd – around 40% every year for 20 years, is expected to keep chronic wasting disease infections at low numbers,” said Wynne Moss, lead author and USGS scientist. If high buck harvests continue consistently (over 20 years), less than 5% of the males on average are expected to be infected. A lower level of hunting pressure, such as 20% of adult males harvested per year, would result in a much higher prevalence of around 30% infected.
The study outlines several non-mutually exclusive mechanisms by which buck harvest reduces CWD spread:
- Removal of infected individuals: Mature bucks often have higher infection rates; removing them reduces the number of infectious deer.
- Shortening the infectious period: Harvest removes infected animals earlier in the course of disease, shortening their time to transmit prions.
- Demographic shifts: Reducing adult male density lowers contact rates among high-risk groups.
- Density effects: Overall deer density (and thus contact opportunities) declines, slowing transmission.
The study also showed that a high buck harvest over a shorter period — 3 years in a row — still curbed the spread of the disease but was not as effective as high harvest numbers over multiple decades.
“Our results suggest that the use of hunting is a promising, scientifically supported way to manage chronic wasting disease; however, it is important to note that this approach is more likely to slow the disease down than eradicate it,” said Paul Cross, co-author on the study and USGS scientist. “This study provides important evidence about the effects of hunting on wildlife disease management for deer.”
