March 16, 2014 at 2:50 am #2475MikeKeymaster
1 in 4 deer in Iowa, western Dane counties has chronic wasting disease
Paul A. Smith
Tom Carlson, a biologist with the Department of Natural Resources in Spooner, holds a lymph node taken from a white-tailed deer at a chronic wasting disease check station in Shell Lake last November. New figures from the DNR show incidences of CWD on the rise in affected areas.
By Lee Bergquist of the Journal Sentinel Feb. 25, 2014
Chronic wasting disease continues to spread in western Dane and Iowa counties, where about 1 in 4 male adult deer is believed to have the fatal deer malady.
The Wisconsin Department of Natural Resources reported on Tuesday a prevalence rate of nearly 25% in adult male deer based on 2013 test results in a management zone where the disease was first detected more than a decade ago.
That’s more than double the figure of 2002, when 8% to 10% of adult males had the disease, according to the agency.
By contrast, the prevalence of the disease is much lower in northern Illinois, where targeted sharpshooting has been used by Illinois wildlife officials since 2002. The prevalence rate is under 1% in Illinois’ 12-county CWD area.
A year ago, the DNR reported a prevalence rate in the zone west of Madison was more than 20% in adult males. The agency cautioned against making year-to-year comparisons because sampling isn’t uniform between years.
But the long-term trend is clear: The rate of infection is rising, the prevalence is higher among male deer than female deer and it’s higher among adults than yearlings, according to conservation officials.
Tamara Ryan, chief of wildlife health at the DNR, said it’s difficult to say what will happen in the coming years. But she noted the region has more deer than its carrying capacity and the disease spreads via contact between deer.
Chronic wasting disease is a nervous system disorder in deer, elk and moose and belongs to a family of prion diseases known as transmissible spongiform encephalopathy. It’s believed to spread by contact between animals — the saliva, urine and feces of infected deer — and indirectly from a disease-contaminated environment, such as soil.
In addition to the situation with adult males, the DNR reported a prevalence rate of about 10% among adult females, compared with 3% to 4% in 2002.
Among male yearlings, the rate is about 7%, compared with about 2% in 2002.
Among female yearlings, the rate is about 6%, compared with about 2% in 2002.
“Those numbers are exactly what we have seen in the past,” said Bryan Richards, CWD project leader for the National Wildlife Health Center in Madison, which is part of the U.S. Geological Survey.
In one area, in Wyoming Valley, south of Spring Green, the infection rate among male adults was more than 30% in 2012 — a year earlier than the latest results.
David Clausen of Amery, a veterinarian who served on the Natural Resources Board until last year, is a proponent of the DNR taking a more aggressive role in trying to control CWD.
Clausen expects the prevalence of the disease to increase and spread if “people choose to ignore reality,” he said, and continue to balk at measures to reduce deer numbers to help control the disease.
The disease has been found in 18 counties of Wisconsin but is concentrated in two zones — the area west of Madison and another in Rock and Walworth counties and northern Illinois.
Chronic wasting disease was detected for the first time in 2002 in Wisconsin; it was first found in captive mule deer in Wyoming in the 1960s.
The discovery, a watershed moment in Wisconsin conservation, prompted the DNR to take aggressive action by using sharpshooters and longer hunting seasons.
In 2007, the DNR defended the use of sharpshooters as an “efficient and effective tool in reducing deer numbers and removing diseased deer,” because the shooters were killing more antlerless deer than hunters were.
Between 2002 and 2011, the DNR spent more than $45 million to manage the disease, with much of the money coming from the federal government.
But the sharpshooting and longer seasons met with strong public objections and reluctance of hunters to kill more deer. Meanwhile, the disease was popping up in new areas.
That prompted the DNR and the Legislature to curtail some control tactics. Sharpshooting was eliminated. So was an early season on antlerless deer. The Legislature eliminated a program known as “Earn a Buck,” which required hunters to kill an antlerless deer before earning the right to shoot a buck.
Ryan called the DNR’s role a “balancing act,” between biological considerations and social and political pressures.
“Right now, while there are people concerned (about the spread of CWD), there isn’t support for the action to really make a difference,” she said.
Starting this year, new rules approved by the Wisconsin Legislature that grew out of a report from a governor-appointed deer trustee include the creation of county deer committees. The deer panels give the DNR flexibility to work locally on deer management and disease surveillance.
“The future of how the DNR is going to contend with CWD will come out of these committees,” Ryan said.
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