The state Department of Conservation hopes to collect up to 165 more samples this winter from deer in Jefferson, Ste. Genevieve and St. Francois counties to expand its study of chronic wasting disease.
Landowners inside a five-mile radius of the positive test found in November will be authorized to kill additional deer, or they will be asked to allow access to their property for conservation department teams to shoot more animals for testing.
Jasmine Batten, wildlife disease coordinator for the state, said the protocol that has been used since the disease was first discovered in Missouri in 2010 is to collect up to 300 samples from the target area. Samples collected during the regular season resulted in testing for 135 deer.
“Because Ste. Genevieve and St. Francois counties were not part of the CWD Management Zone (during the fall season) we have only a handful of samples from those counties within the surveillance zone, so a greater emphasis on collection in those counties will occur,” Batten said.
The additional testing strategy in the past has resulted in additional positive samples in Macon and Adair counties, but not in Linn and Cole counties, Batten said. If the expanded sampling does not reveal more positives after a few years, the targeted effort may be reduced.
“This doesn’t mean the disease is not truly there,” she said. “It may just be at such a low prevalence that it is difficult to test enough deer to detect it again.
“The bottom line is, we are detecting very few positives through our surveillance overall, which is a good thing.”
More than 1,000 Jefferson County deer were tested this fall through mandatory sampling, participating taxidermists and other opportunities, such as road kills, sick deer and voluntary testing at conservation department offices.
“The best-case scenario is we sample for three years, meet our goal, find no positives and then back off,” Batten said. “Local deer populations on a smaller scale are fairly robust to similar population fluctuations, and in the long run, if we don’t find CWD to be established there, data would suggest the populations would recover.”
Testing in Missouri so far has shown a greater incidence of the disease in older bucks, so collection of additional samples will attempt to target those populations.
“Generally speaking, because of its long incubation period, CWD is found at higher rates in older animals, and it is overall usually found at a higher rate in males,” Batten said. “It is likely these differences have to do with behavior; males are more likely to come into contact with a greater number of social groups and therefore have a greater chance of being exposed to the disease.”
Of the 39 positive results found in Missouri, only 12 have been females, but that buck-to-doe ratio is not perfect science because it doesn't take into account how many of each sex have been tested.
The additional testing will be a boon for food pantries, which will receive at least a portion of the venison from animals that test free of the disease.
“All deer are tested for CWD and taken to a local processor. Meat is either returned to the landowner or donated to Share the Harvest,” Batten said.
Testing in the 29 counties is likely to continue for the foreseeable future, and Ste. Genevieve and St. Francois counties are likely to be added next fall. Landowners inside the five-mile radius already have been contacted about participating.
The additional sampling this winter will end when 165 are collected or by March 15, whichever comes first. Testing is done by an independent lab, and each initial screening test costs $17. The follow-up test to confirm any positive result is $35, Batten said.
“It's a significant investment, but it reflects our commitment to the issue and the long-term health of the state's deer herd,” she said. “In order to find the disease before it is widespread or well established, you have to test a lot of animals. The motivation to detect the disease very early in the infection is because we believe this gives us the best chance to slow – or maybe even stop – the disease.”
John J. Winkelman is community relations manager at Mercy Hospital Jefferson. If you have news for the Leader’s Outdoor News page, send an email to ogmjohnw@aol.com. You also can follow John on Twitter at @johnjwink99.