COMMENTARY BY DR. DAVE SAMUEL
Chronic Wasting Disease is as nasty for deer as the COVID-19 is for people. Maybe worse. True, we don’t have CWD in deer anywhere near us here. In fact, the only place it is found in West Virginia is in the Eastern Panhandle. Counties to have officially reported CWD are Berkeley, Hampshire, Hardy, Morgan, and Mineral, with the first being found in 2005, then more in 2008 and 2011. Since that time many more positive CWD deer have been found in those five counties, but none anywhere else in West Virginia.
As I’ve noted in former columns, CWD is not caused by a bacteria, and not a virus. It’s a mutated protein that is called a prion, and prions literally destroy the brain. The nasty thing about prions is that they are indestructible. Most chemicals do not destroy them. Heat does not destroy them. Once an infected deer deposits the prions via mucous, urine, or feces, they remain viable for years. Biologists have no idea how long they remain viable in the soil. We do know that it’s at least 10 years. Most suspect 20 or 30 years. I believe they remain viable even longer.
How does the disease spread once it occurs in an area? In other words, how do prions get spread in the environment? As mentioned, they are deposited by infected deer. Once on the ground, studies show that plants such as alfalfa pick them up and when that plant is eaten by a healthy deer, it gets the disease. That deer may not show symptoms, but it has the disease. (Sounds a bit like COVID-19 doesn’t it?). One study showed that crows can carry them around. And infected yearling bucks that disperse from their birth home range, an average of five miles in forested habitats, take the prions with them.
I suspect that if they end up in streams, water will carry them downstream. As you can see there are several ways that CWD has slowly spread in the Eastern Panhandle. If you get the impression that once prions are in the environment, CWD will be impossible to eliminate, then you are right.
If we can’t stop the spread of CWD, can we at least slow it down? The answer is yes. The number one technique used to slow the spread is to lower deer numbers, and lower them significantly. Of course this isn’t what hunters want to hear. They love seeing lots of deer. And they love seeing older bucks, which is why some states implemented antler restrictions. In some states you cannot shoot a buck until it has at least four points on one side. Such bucks are usually at least two years of age. Lowering deer numbers including bucks, doesn’t sit well with hunters. Can’t say that I blame them.
Over the past 15 years or so there has been a trend in state deer management programs to protect yearling bucks and let them age before harvest. Even though such management is favored by most hunters, the trend to protect yearling bucks from harvest may change because of CWD. At least one state, Missouri, has taken a step back by eliminating antler restrictions (a practice that protects yearling bucks) and encouraging hunters to shoot yearling bucks before they disperse. It is one technique to slow the spread or CWD. Is it working? Only time will tell.
The other aspect of increasing the kill, is to harvest more does. As deer numbers decrease in an area, the idea of harvesting more does won’t, and doesn’t, sit well with hunters, and maybe non-hunters, too. Hunters and non-hunters like seeing more deer.
At this point the best thing that could happen would be that we do not get CWD in any other part of the state. OK, but how do you prevent the disease from cropping up in new areas? There are several answers here, but the number one thing to do is to curb deer farms. CWD often gets its start in deer farms and when one deer farm sends a CWD deer to another part of the state, or to a farm in another state, the disease spreads. The prions inside a deer farm fence don’t know the boundary of that fence and can end up outside the fence and infect wild deer in that area. It has happened often in the past.
In our state, when CWD pops up many miles from the Eastern Panhandle, it will probably be because of contaminated deer on deer farms. We don’t have many farms, but that is what will probably happen.
Given all that, most hunters aren’t all that concerned about CWD. They point out that no human has gotten the disease from eating meat from infected deer (and thousands of hunters have eaten prion-infected meat). Studies show that hunters believe this stuff is bad, but the realities of slowing the spread by increasing the deer harvest is not supported by many hunters.
Just as with COVID-19, states want data to help them decide how to manage deer herds when CWD is in the picture. Most states collect parts of dead deer and look to see how many have CWD. It gives the states an idea of how fast and how far the disease has spread, and helps those states decide what their management strategy will be. My brother in Alberta sent me the 2019 surveillance data for CWD in that province. CWD was first detected on a game farm in Alberta in 2002. Then a farmed elk was found with the disease. The first infected wild deer was found on the border of Alberta and Saskatchewan and it was a mule deer. In fact, in Alberta, mule deer have a bigger CWD problem than whitetails. The concern Alberta officials had with Saskatchewan was the fact that elk farms in the province were major spreaders of the disease.
From 2005 on, many harvested whitetails and mule deer were sampled along the Saskatchewan border and as the years went by the infected numbers increased. Starting in 2005 when CWD animals were found in an area, the province initiated winter control programs to reduce animal numbers. This meant that after the hunting season, more animals were harvested. This brings me to the data my brother forwarded.
Of 10,400 deer heads tested, CWD was detected in: 17.5 % of 5,632 mule deer; 3.9 % of 4,295 white-tailed deer; 1.3 % of 231 elk; 0.9 % of 232 moose
The following data were of special interest to me. They had species and gender data for 9,877 deer, and CWD was detected in: 24.5 % of 3,133 male mule deer; 8.8 % of 2,485 female mule deer; 4.8 % of 3,226 male whitetails; 1.4 % of 1,033 female whitetails.
As you can see, bucks are more likely to have CWD, probably because they are exposed to CWD in the wild (lick urine of females in the rut, hang out in buck groups in September and thus get it from other bucks, etc.) more than does. Thus the prevalence in bucks is higher.
I might add that states such as Wisconsin and Wyoming report much higher rates of infection for whitetails than what was reported in Alberta. In addition, and very alarming, is the fact that in states where data have been collected on ages of deer that are infected (e.g. Wisconsin), older bucks have the highest rate of infection.
Older bucks are the ones hunters want to harvest, and time will tell whether CWD in the Eastern Panhandle is lowering the numbers of older bucks.
CWD is always fatal, so some have asked why we don’t find large numbers of dead deer laying around in the woods in places like Hampshire County. The answer comes from data showing that deer with CWD, even if they don’t show symptoms, are more easily taken by predators. Also, deer with CWD have a higher mortality from automobiles than deer without CWD. Deer with CWD are harvested by hunters at a higher rate than deer that do not have CWD. You don’t find a lot of dead bucks laying around the woods, killed by CWD, because they have already died from other causes. If they didn’t have CWD, more would escape predators, more would dodge vehicles and thus, more older bucks would be out there for hunters to harvest.
Just like COVID-19, CWD is deadly, complicated and difficult if not impossible to eliminate. We may come up with a vaccine for COVID-19, but even if you could find a vaccine for CWD, how would you administer it? Lots of questions about CWD, but for now, there is no reason to panic. Be concerned, collect data, support the DNR policies, and go deer hunting. Social distancing in the deer woods is far easier than most places. This fall, I’ll see you out there.
