For those who are trying to puzzle out the best strategy for managing chronic wasting disease, 2006 is very much an experimental year.
Wildlife officials and UW-Madison researchers are closely watching for results of new control strategies designed to contain the disease in the southern part of the state.
Researchers are also employing landscape genetics technology to better understand how deer move and how various herds are related.
The largest change from last year is the compression of the white-tailed gun deer season. By shortening the season to a more traditional Thanksgiving-week hunt, the Department of Natural Resources hopes to control this prion disease, and in the process, increase hunter satisfaction.
Part of the thinking is that the shorter season will make the deer more vulnerable, explains Scott Craven, chair of the wildlife ecology department in the UW-Madison College of Agricultural and Life Sciences. Wildlife specialists also hope it will minimize competition for hunters’ time from other activities, such as other recreational endeavors, family holiday gatherings and football.
“We”ll have to find out how these changes in regulations affect the population of deer,” says Michael Samuels, a wildlife ecologist at UW-Madison and the Assistant Leader of the USGS-Wisconsin Cooperative Wildlife Research Unit.
Samuels researchers continue to address several key questions in their effort to demystify the disease that has infected at least 652 deer in the state since surveillance began in 2002:
-How is CWD transmitted through the environment (via soil, deer scrapes, or other animals) and how does this compare to deer-to-deer transmission?
-Why are bucks twice as likely as does to be infected?
-Does the rate of CWD infection depend on the density of deer in a particular area or not?
-How fast is the disease spreading across the landscape?
Answering these questions is likely to take some time, Samuel says, particularly because a deer infected with CWD may take up to two years to reach the stage at which it becomes clinically ill.
“Even if we started a successful strategy to manage the disease two years ago, it would probably be three to four years or even a little longer before we saw a decline in prevalence,” he says. “It is going to take a lot of patience on everyone”s part to figure out what is going on, and whether we”re successful.”
One of the newer tools that Samuel will be using this year is landscape genetics, which allows researchers to assess the relatedness, breeding and movement of the deer population.
“We”re doing some pilot work on this right now to test it, and it’s looking very promising,” Samuel says.
The initial testing has revealed more genetic connectedness between deer in the Mount Horeb area and those in forested areas to the west than between deer in the Mount Horeb and north toward the Wisconsin River or toward Madison. This type of research tool could help Samuel and other researchers determine whether highways or rivers are barriers to the spread of CWD, and devise new management plans accordingly.
“If you look at the maps of where they detected positive animals, you’ll see that last year there were a lot more positive detected outside the eradication zone,” Samuel says. “What it made us realize is that the disease is probably distributed over a larger geographic scale than a lot of us expected. Even under optimistic scenarios, it looks like we”re going to be at this for awhile.”
For more information on CWD, 2007 deer seasons, and hunting regulations, visit the Department of Natural Resources website at http://www.dnr.state.wi.us/org/land/wildlife/whealth/issues/CWD/.