The 2020 surveillance of Iowa’s wild deer herd for the presence of chronic wasting disease has yielded 21 new positive deer, and has added two new counties to the list where CWD-positive deer have been found.
The new positive deer were all from either an existing CWD zone or adjacent to an existing zone. Two new counties were added to list where deer have tested positive.
Jackson County had a positive deer that was taken just south of the existing Dubuque disease management zone, and Appanoose County had a positive deer taken just northeast of the existing Corydon disease management zone.
“Although we expect some spread just outside of our existing zones, it’s not what we like to see,” said Tyler Harms, deer program leader. “We will reassess the boundaries of our existing zones to encompass these new positives.”
The Iowa DNR has updated the map showing where the positive deer have been taken.
To date, 111 wild Iowa deer have tested positive for the disease since 2013 when it was first discovered in the state.
“We rely heavily on our hunters to help us respond to this disease by increasing antlerless harvest in our disease management zones,” Harms said. “We know increased harvest is the best way to slow the spread and it helps increase sampling in these zones so we can monitor disease prevalence and spread. We continue to encourage hunters to harvest additional antlerless deer in these disease management zones.”
The 2020 sampling year ends March 31, and while most of the deer samples are collected during the hunting seasons, the DNR collects samples from road killed deer and suspected sick deer near the deer disease management zones annually, beginning April 1.
The winter of 2021 winter has been tough on deer.
For wildlife, surviving an average Iowa winter is challenging enough. When the winter includes consecutive days where temperatures don’t cross above zero and new snow arrives weekly, survival can become extremely difficult.
“Every winter we lose wildlife but in winters like this, we do expect some additional mortality,” Harms said. “While people may think it’s a good idea to put out a pile of corn for the deer to eat, it actually causes more harm than good. Perhaps the biggest issue with feeding deer is the increased risk of spreading disease through the local herd.”
Artificially congregating deer in close quarters, like over a pile of corn, increases the likelihood of disease transmission to other deer.
“All it takes is for one deer to be infected with a disease to stop by, feed on the corn and leave its saliva and urine behind for there to become an outbreak,” Harms said. “But beyond disease transmission, feeding deer can cause other health issues.”
In winter, a pile of corn is the equivalent to a pile of candy, Harms said, and too much candy is not good for anyone. “There is other food available that is better for them,” he said.
It’s also important to not set out grains because it changes deer behavior.
“When the snow is deep and it’s hard to find food, deer will adjust biologically to the situation to conserve energy,” he said. “They will congregate in places where there is shelter and they can conserve their energy.
Placing food out will cause them to change that behavior, possibly expending more energy to get to the grain than they will gain by eating it.”