Federal sharpshooters killed 238 deer and discovered two new cases of chronic wasting disease (CWD) inside a concentrated area of southeastern Minnesota’s disease management zone before ending their campaign Sunday.

Lou Cornicelli, the leading big game researcher for the Department of Natural Resources (DNR), said the agency is finished with a three-pronged effort that removed and tested 1,133 adult whitetails from Fillmore County since Dec. 31.

Including all test results dating to November, the DNR confirmed CWD in 10 deer clustered between Preston and Lanesboro. An 11th case was documented five miles north of the cluster.

Thinning the herd in Fillmore County became a DNR priority in November when the outbreak was detected in two whitetails shot by hunters one mile apart.

The fatal neurological disease is contagious among deer, making it important for wildlife managers to narrow the chances of deer-to-deer contact during an outbreak.

The same strategy appeared to stop Minnesota’s first outbreak of CWD in wild deer when it was discovered six years ago in a single whitetail near Pine Island.

After nearly 3,000 deer were harvested inside the disease zone and tested for CWD during the regular hunting season, the DNR authorized a special two-week hunt that began Dec. 31. The landowners in the area received special shooting permits to add to the removal effort.

Cornicelli estimates a 10 to 15 percent reduction in deer density for the disease management zone. In the pocket of land between Preston and Lanesboro targeted exclusively by sharpshooters, the herd purposely was reduced by more than 15 percent because the disease was concentrated there.

The DNR said it responded aggressively to the outbreak because it believes the disease originated from a single source of infection and can be stopped. The source of that infection is still under investigation.

“I don’t think we are dealing with something that has spread across the landscape,” Cornicelli said Tuesday.