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Wasting disease prevalent in early tests

Presence in 2 counties’ deer likely goes back a decade, Game & Fish official says by Bryan Hendricks | April 21, 2016 at 5:45 a.m.

After completing its first phase of testing deer for chronic wasting disease in north Arkansas, the state's Game and Fish Commission acknowledged Wednesday that the disease likely has been present among deer and elk in Newton and Boone counties for at least a decade.

Brad Carner, chief of the Game and Fish Commission's wildlife management division, confirmed Wednesday that 62 of the 266 white-tailed deer the commission sampled from March 14-24, or 23 percent, tested positive for the disease. The first phase of testing was confined to a small area in Newton and Boone counties.

"Those were randomly sampled deer that appeared to be healthy," Carner said.

Additionally, the commission tested nontargeted deer and elk inside and outside the 125,000-acre sample area near the Buffalo National River. In all, 79 deer and three elk tested positive.

A deer killed in a vehicle collision on Arkansas 7 about 7 miles south of Jasper tested positive, as did a roadkill deer about 10 miles northeast of Harrison, near the Missouri border.

"What we found is that it [chronic wasting disease] is pretty widespread throughout the whole area," Carner said.

Chronic wasting disease is a transmissible syndrome caused by mutant proteins, called prions. Similar to mad cow disease, it destroys the central nervous system, but it only affects cervids such as elk, white-tailed deer, mule deer and moose. Prions endure in the environment indefinitely, but there has been no case of humans contracting the disease.

Despite the prevalence of the disease in the initial results, Carner said he doesn't believe that the Game and Fish Commission was lax in its testing before the state's first case of the disease was discovered in an elk killed by a hunter in October in Newton County.

"I don't feel that we let our guard down," Carner said. "As we look back at how we were sampling, I think we were very prudent in our approach. We did three years of blanket sampling across every county, and we've been sampling every elk hunt since day one, when we had our first elk season in 1998. We focused our efforts around captive facilities, and we went above and beyond other states in our surveillance.

"It's unfortunate that it did fly under the radar for a number of years, but I am still very comfortable in the way we did our surveillance."

To limit the spread of the disease beyond north Arkansas, Game and Fish Commission Director Mike Knoedl recommended that the commission consider banning the baiting of deer with corn and eliminating mineral blocks, a known transmission medium for the disease.

Corn and mineral blocks can draw deer into an area. Infected deer can transmit prions into the ground in those areas, which can lead to the spread of the disease to other areas.

"Baiting is the pink elephant in the room that you guys are going have to deal with," Knoedl said. "I think that's a Band-Aid you need to rip off at once."

Carner said Wednesday that of the 189 female deer tested in the first phase, 37, or about 20 percent, tested positive for the disease. Of the 77 bucks sampled, 25, or about 30 percent, tested positive.

Most of the deer that tested positive were between 2½ and 3½ years old, Carner said. Six were age 5 or older. Twelve of the bucks were between 2 and 2½ years old.

"Twelve animals that were less than a year old tested positive, which is concerning," Carner said.

A deer does not contract the disease in the womb, Carner said, but it can contract it immediately after birth when an infected doe grooms the fawn by licking.

"It appears that those animals are coming in contact with a large enough quantity of prions from day one that they are testing positive quicker," Carner said. "Either there's so much more prions in the environment that they're picking it up apart from the mother, or something. That's a high number."

Carner said he does not know how quickly the disease will kill infected fawns, but high fawn mortality will affect deer herds.

"Most does are going to be 2½ years old before they have their first fawn," he said. "If does start dying from the disease before they start reproducing, we could have a population crash."

In response to Knoedl's proposal to ban baiting, commission member Andrew Parker of Little Rock said it could have a severe economic effect. He said the Wal-Mart distribution center in Northwest Arkansas moved 22,000 pallets of corn in 2015.

Knoedl said he doesn't believe that banning baiting will hurt merchants because they don't make a large profit on selling bagged deer corn. He said corn is an inducement for customers to buy other goods, such as snacks and soft drinks.

Commissioner Ken Reeves of Harrison said banning baiting would be prudent and consistent with the commission's mission.

" [Chronic wasting disease] is passed from positive to negative [animals] at salt licks," Reeves said. "The No. 1 transfer is saliva. Baiting goes counter to what we've been telling people forever, which is to provide habitat."

White-tailed deer seem to be more susceptible to the disease than elk are, Carner said. Even in Colorado, where the disease was first identified in elk, prevalence rates are below 13 percent in elk since 1981, Carner said.

Wisconsin is the national case study for the disease's progression, Carner said. The Wisconsin Department of Natural Resources discovered the disease in deer in 2002. Iowa County has the highest prevalence rate. Initially, the prevalence rate in Iowa County was 3 percent of bucks and 2 percent of does, Carner said. In 2015, the prevalence rate was 40 percent among bucks and 23 percent in does.

"Since 2002, they've sampled 195,000 deer," Carner said. "They were hoping to eradicate it. We know now that's not possible."

Cervids transmit prions primarily through saliva and urine. Prions have been proved to bind to soil, and they bind efficiently to plants, where they can persist for years.

Prions are not destroyed through traditional disinfection methods such as chlorine bleach, boiling or ultraviolet radiation, nor do they degrade over time. The only proven method for destroying prions is incineration, but prions have been known to remain viable after being exposed to temperatures of 1,800 degrees Fahrenheit.

Steven Beaupre, a professor and chairman of the department of biological sciences at the University of Arkansas, said the prevalence level in Newton and Boone counties suggests that the disease has probably been present for at least 10 years.

"The topography of Iowa County is very similar to the Ozarks," said Beaupre, who is a member of the commission. "There's a lot of karst and rough areas and rivers. The deer densities there are much higher than they are here."

To determine the limits of contamination in Arkansas, where the deer herd is estimated at 1 million, Beaupre said it would be helpful to test at least as many deer as have been tested in Wisconsin.

"If we could run 190,000, 200,000 deer in a year, we could nail down accurately what the limits of the infection are here in the state," Beaupre said. "To run [tests on] the amount of deer we shoot in our state would probably cost $6 million. That's a chunk of change."

Metro on 04/21/2016

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