As chronic wasting disease (CWD) continues to spread across Virginia, landowners who have confirmed CWD in a deer harvested on their property may have questions about what they can do in terms of managing the deer on their land after an initial CWD detection. Below is some important information about CWD that may affect management actions.
The Infectious Agent That Causes CWD
- CWD is caused by a prion, which is a mis-folded protein molecule.
- Prions do not reproduce. Rather, they cause other normally folded protein molecules of the same sort to mis-fold as well, leading to fatal brain damage.
- Prions are extremely tough. They remain capable of infecting deer for years after deposition on the landscape.
- Deer can be infected and transmit the infection to other deer for years before showing any symptoms.
- Prions persist for many years in the dirt and remain capable of infecting deer that consume them.
- Prions can be taken up into grasses through their roots, potentially infecting animals eating them.
- Prions are found in various deer body fluids: urine, saliva, feces, nasal discharge, etc.
- Prions can be found in many animal tissues but are most concentrated in the spinal column, lymph nodes, tonsils, and brain.
- Bucks are more likely to be infected than does. This is likely due to certain aspects of deer behavior, such as:
- Does mostly interact with other deer in their family group, and neighboring groups of does will generally avoid each other.
- Does seldom travel far from the place of their birth, usually no more than a few miles.
- Bucks travel much more widely than does and come into direct contact with many other traveling bucks and with many more does, most notably during the rut (i.e. breeding season).
What can a landowner do on their property to try and reduce the spread of the disease from infected deer to healthy deer?
Do Not Leave Carcass Parts on the Landscape
- Keep prions out of the soil and plants by disposing of carcasses (and gut piles) in a lined landfill or a hole greater than 4 feet deep. While neither method destroys the prions, the goal is to keep them away from plants and animals for the years it takes for them to degrade.
Report Sick Deer to the DWR to be Dispatched and Tested
- By the time a deer is showing visible symptoms it has been spreading CWD prions for months to years. CWD symptoms include emaciation, a wide-based stance and swaying gait, lowered head and drooping ears, a lack of fear of humans, and drooling.
Immediately Discontinue All Feeding of Wildlife and Remove Mineral Licks for Deer
- Feeding and extra mineral licks cause deer to congregate and share saliva and other fluids in/around the feed. This increases the chance of the disease spreading.
Reconsider Food Plots
- While food plots do not concentrate deer as much as feed piles, artificial plantings can cause deer to congregate more than they would in their natural habitat. This leads to a greater risk that deer will transmit prions to other deer using the same small area.
Reconsider Killing Predators Like Coyotes and Bobcats
- Predators selectively kill the sick and unwary. CWD impacts the brain and infected animals are likely less aware of their surroundings. Infected animals are known to be more likely to die from any cause (vehicle collision, predation, etc.) then non-infected deer, even early on in the course of the disease before visible symptoms develop. The faster an infected deer is removed from the landscape, the fewer prions it will spread.
Increase Deer Harvest
- This appears to be the only strategy that shows any signs of success at a regional level. Reducing the number of deer in an infected area will lower the contact between animals, and between populations, and will reduce the pressure to disperse. While this won’t eliminate the disease from a small local herd it may help to avoid spreading CWD to new populations. This includes the killing of more bucks as they are more likely to be infected than does and also travel further.