Veterinarian: Iowa faces surge in fatal deer disease

Iowa is likely to see a second straight surge in cases of a fatal deer disease this winter, a state veterinarian said.

In an interview, Dr. Rachel Ruden of the Iowa Department of Natural Resources said the state’s confirmed cases of chronic wasting disease doubled last season and now stands at 91.

She predicts another jump in confirmed cases this season.

“That’s what chronic wasting disease does,” Ruden said. “Once it gets into an area, it intensifies and spreads geographically. I expect more cases this year.”

The disease is fatal to whitetail deer and also kills elk, moose and reindeer. It attacks the brain, causes weight loss, and alters behaviors before killing the deer. It has not been shown to transfer to humans, but research continues, DNR reported.

Wisconsin has fought to prevent exponential growth of CWD, which Iowa could face within a few decades, Ruden said. “That’s the concern,” said Ruden, who also works part-time at the Veterinary Diagnostic Laboratory at Iowa State University.

In the past year, the disease has been confirmed in four additional counties in Iowa — Fayette, Winneshiek, Decatur and Woodbury. Ruden said the Woodbury case is a bit odd because Nebraska doesn’t have many cases, but Illinois, Missouri, Minnesota and Wisconsin do.

The disease also has been confirmed in the Iowa counties of Allamakee, Clayton, Wayne and Dubuque.

CWD is most likely already in more than the eight confirmed Iowa counties, Ruden added. “It’s kind of the luck of the draw” whether the state’s 7,300 tests a year find cases in each area, she added. Tests are conducted on samples from all 99 counties.

No one has a good figure for how many deer there are in Iowa, but for perspective, hunters kill close to 100,000 a year. The state is calling on hunters to share tissue samples of deer they kill.

Ruden said state biologists are urging people not to set out salt licks or food for deer, because that encourages deer to gather. The disease is spread from animal to animal directly, and via urine and saliva on surfaces.

In Wisconsin, where the disease spread before it was confirmed in Iowa in 2013, half of the adult male bucks test positive for CWD in the areas that have outbreaks. Ruden said infected deer have a 50% lesser chance of surviving the year once they are infected, and the disease can emerge as much as two years after exposures.

Chronic wasting disease is caused by an abnormal protein called a prion that can’t be controlled with chemicals, said DNR biologist Tyler Harms. The disease is spread from deer to deer directly and through saliva and urine on the ground and surfaces.

DNR collects deer tissue samples donated by hunters, from road kill deer, and from animals that are obviously sick and showing the tell-tale behavioral changes, Ruden said.

The state has confirmed 91 cases of CWD in Iowa, 44 in the 2019-20 season, records show. Iowa began tests in 2002.

The illness has been linked to shrinking populations of white-tail deer nationally.