FAYETTE - Bryan Richards, Chronic Wasting Disease specialist with the U.S. Geological Survey National Wildlife Health Center in Madison, spoke to approximately 25 members of the Fayette Sportsman's Club Tuesday night about the "spooky" developments in some parts of the western United States.
"Adult male deer have about a 33 percent chance of acquiring CWD in some parts of Colorado and Wyoming," Richards warned, while does are somewhat less likely to contract the disease. Neither a virus nor a bacteria cause the disease, he said. Instead, CWD is the result of a naturally occurring protein that has changed to a disease causing prion.
Using Hunt Area 65 in Colorado as an example, Richards said hunters are no longer allowed to shoot does, emphasizing instead the harvesting of male deer since they are most likely to carry the disease.
As a consequence of the buck only harvest, the population would be expected to rise. "It's not; it's going down," he said. "Fawn production is also down significantly."
The disease was first detected in a fenced facility near Fort Collins, Colo. in 1967, Richards explained, and has now reached a level of prevalence at which the deer population is beginning to decline as a result.
Near Boulder, Colo., officials report a 50 percent population decline over the past 20 years. In addition, outfitters who make their living by offering hunts for mule or white-tailed deer are not seeing the five- and six-year-old deer that were once abundant.
In Wisconsin, disease prevalence in the core area in western Dane County and eastern Iowa County has now reached approximately 10 percent. Other areas within the CWD Management Zone have infection rates of less than one percent, Richards claims.
However, this assessment does not take into account the reduced level of testing that now exists within the CWD Management Zone and the relatively long distances some must travel to reach a collection facility. Also left unexplained are the occurrences of so-called spark zones, like the one near Hollandale in Iowa County and in the Devil's Lake area of Sauk County where higher prevalence levels exist.
Richards suggests that infection rates will stay relatively low for several years, but will eventually start to rise. "Out west, the disease started slow and then began to spread rapidly."
He believes the disease has existed here in Wisconsin for at least 20 years. The DNR began testing deer for CWD in 1999.
Also problematic from a population management perspective is the results of public surveys that suggest hunters will go elsewhere to hunt when prevalence rates reach 40 percent or more. If that occurs, according to Richards, an immediate population explosion will occur, leading to even higher rates of infection, followed by a steady decline in population.
Also of concern is the length of time that the prions remain in the soil after contamination. Richards cited an example in Iceland of a farm that had been depopulated after an outbreak of a prion-related disease among livestock. A shed left unused for 16 years, was determined to be the cause of another outbreak of the disease.
Similar findings occurred at an enclosed deer farm in Echo Valley, Colo. The facility was depopulated, and then later re-opened only to experience another outbreak of CWD. Captive cervids from this facility were shipped to more than a dozen states before it was shut down.
Regarding the Department of Natural Resources new Five Year Management Plan for combating the disease, Richards sees little chance of success for stopping the spread of the disease. The goals and objectives are lofty and appropriate, he suggests, but there is a "disconnect" from the means through which they will be met.
He concludes that words such as "substantially," "significant," and "when warranted" have no clear definition and suggests the agency has decided "it may be easier to not act than to act."
"As long as deer can walk, we can't stop it," he added.
Richards' written comments on the subject were included in the discussion at the August meeting of the Natural Resources Board meeting in Hayward. The Board tabled a motion to approve the Five Year Plan.
- Lee Fahrney is the Monroe Times outdoors writer. He can be reached at (608) 967-2208 or at fiveoaks@mhtc.net.
"Adult male deer have about a 33 percent chance of acquiring CWD in some parts of Colorado and Wyoming," Richards warned, while does are somewhat less likely to contract the disease. Neither a virus nor a bacteria cause the disease, he said. Instead, CWD is the result of a naturally occurring protein that has changed to a disease causing prion.
Using Hunt Area 65 in Colorado as an example, Richards said hunters are no longer allowed to shoot does, emphasizing instead the harvesting of male deer since they are most likely to carry the disease.
As a consequence of the buck only harvest, the population would be expected to rise. "It's not; it's going down," he said. "Fawn production is also down significantly."
The disease was first detected in a fenced facility near Fort Collins, Colo. in 1967, Richards explained, and has now reached a level of prevalence at which the deer population is beginning to decline as a result.
Near Boulder, Colo., officials report a 50 percent population decline over the past 20 years. In addition, outfitters who make their living by offering hunts for mule or white-tailed deer are not seeing the five- and six-year-old deer that were once abundant.
In Wisconsin, disease prevalence in the core area in western Dane County and eastern Iowa County has now reached approximately 10 percent. Other areas within the CWD Management Zone have infection rates of less than one percent, Richards claims.
However, this assessment does not take into account the reduced level of testing that now exists within the CWD Management Zone and the relatively long distances some must travel to reach a collection facility. Also left unexplained are the occurrences of so-called spark zones, like the one near Hollandale in Iowa County and in the Devil's Lake area of Sauk County where higher prevalence levels exist.
Richards suggests that infection rates will stay relatively low for several years, but will eventually start to rise. "Out west, the disease started slow and then began to spread rapidly."
He believes the disease has existed here in Wisconsin for at least 20 years. The DNR began testing deer for CWD in 1999.
Also problematic from a population management perspective is the results of public surveys that suggest hunters will go elsewhere to hunt when prevalence rates reach 40 percent or more. If that occurs, according to Richards, an immediate population explosion will occur, leading to even higher rates of infection, followed by a steady decline in population.
Also of concern is the length of time that the prions remain in the soil after contamination. Richards cited an example in Iceland of a farm that had been depopulated after an outbreak of a prion-related disease among livestock. A shed left unused for 16 years, was determined to be the cause of another outbreak of the disease.
Similar findings occurred at an enclosed deer farm in Echo Valley, Colo. The facility was depopulated, and then later re-opened only to experience another outbreak of CWD. Captive cervids from this facility were shipped to more than a dozen states before it was shut down.
Regarding the Department of Natural Resources new Five Year Management Plan for combating the disease, Richards sees little chance of success for stopping the spread of the disease. The goals and objectives are lofty and appropriate, he suggests, but there is a "disconnect" from the means through which they will be met.
He concludes that words such as "substantially," "significant," and "when warranted" have no clear definition and suggests the agency has decided "it may be easier to not act than to act."
"As long as deer can walk, we can't stop it," he added.
Richards' written comments on the subject were included in the discussion at the August meeting of the Natural Resources Board meeting in Hayward. The Board tabled a motion to approve the Five Year Plan.
- Lee Fahrney is the Monroe Times outdoors writer. He can be reached at (608) 967-2208 or at fiveoaks@mhtc.net.
