After three more deer from Allamakee County have tested positive for Chronic Wasting Disease (CWD), Iowa DNR officials hope to use “a surgical approach” to head off a more widespread outbreak of the always-fatal disease that affects deer, elk, and moose. The three animals were among 309 tested in Allamakee County after the 2014 hunting season. (The first case of a wild Iowa deer with CWD was confirmed there in an animal taken in the 2013 season.)
Dale Garner, chief of the DNR’s wildlife bureau, Tuesday sought input from more than 100 people each at two public meetings in Waukon and Harpers Ferry. He then outlined a scenario by which the agency could collect samples from about 200 more deer to help gauge the severity of the situation.
Garner proposed issuing free “scientific collection permits” to people who agree to shoot deer in a 31-square-mile area near Harpers Ferry where the four CWD cases have been detected. Officials estimate the current deer population there at about 1,100. If 200 animals can be shot, that would reduce the herd by about 18%.
Although the rules are not final, Garner said the permit probably would limit a hunter to a specific area where he/she planned to shoot deer, and mandate allowing DNR officials to collect samples for CWD testing. The period for taking deer could begin as early as Feb. 21 and continue through March 8 – although the hunt would be halted if 200 deer were taken sooner. Preliminary rules would allow using any legal firearm, including centerfire rifles, as well as archery equipment.
Garner said he hoped that the four deer with CWD came across the Mississippi River from southwestern Wisconsin, where CWD was first detected in 2002. The incidence of CWD in that part of Wisconsin has risen steadily to a point where 35% of the bucks and 18% of the does are now affected. Initial attempts by Wisconsin officials to eradicate deer in the region were unsuccessful.
Garner was reluctant to suggest such radical measures in Iowa – at least not until biologists have a much better handle on the prevalence of CWD here.
“We’ve got a spark,” he said. “But (Wisconsin) has got a fire.”
“If we can go in and surgically remove it, we have a chance of putting out that spark” before it becomes a fire, Garner said.
If CWD cases are limited to a small area, and the outbreak is caught soon enough, there is some indication that eliminating nearly all the deer in that area can stop its spread, Garner noted.
New York wildlife officials took that approach a few years ago, and CWD so far has not reappeared.
In Illinois, officials believe they have slowed the spread by using sharpshooters to kill family groups of deer suspected of carrying CWD.
But Garner was not ready to call for either tactic in Iowa until biologists can decide how severe the problem is here.
Although chronic wasting disease is similar to scrapies in sheep and “mad cow disease” in cattle, its transmission to humans has never been confirmed. CWD is a slowly progressive, degenerative brain disease caused by a misshapen protein, or “prion,” for which there is no immune response or antibody. Prions persist in the environment, and can only be inactivated by temperatures of more than 1500 degrees.
Prions are most often spread by animal-to-animal contact, as well as in feces, urine, and saliva. Scavengers such as crows and coyotes may carry the prions, but apparently are not affected.
CWD was first identified in 1967 at a Colorado deer and elk research facility. By 1985, it had spread to wild cervids in the region. Many biologists attribute the 2002 outbreak in Wisconsin to the transporting of captive animals. Nearly all of the states surrounding Iowa also have reported CWD in subsequent years.
Iowa began testing for CWD in 2002, and so far has screened 57,000 wild deer and 3,500 captive animals.
And the saga is far from over . . .