Doe afflicted in Seneca is confirmed case.

A fatal deer disease discovered in northern Illinois in 2002 has spread to LaSalle County.

The county’s first confirmed case of chronic wasting disease was a mature doe found late last month on private property in Seneca near the Illinois River.

“It was showing the classic signs of chronic illness,” said Paul Shelton, forest wildlife program manager for the state Department of Natural Resources.

The latest case brings the state’s total to 189 since 2002. Other counties with CWD cases are Winnebago, Boone, Ogle, DeKalb and McHenry.

The vast majority of the cases have been discovered in Winnebago and Boone counties.

Previously, the most-southern case was a single deer found in DeKalb County, about 30 miles north of Seneca.

Shelton thought the deer likely had wandered into LaSalle County from the northern counties. He said deer can travel great distances in a short time. He cited a Wisconsin study in which deer with radio transmitters were tracked. One deer went from Mount Horeb to nearby Madison, crossed the state line and was tracked in Freeport. Then, it returned to the Mount Horeb area.

“This was all in a few months,” Shelton said.

The DNR has sampled LaSalle County deer for CWD tests in the past, but didn’t last season.

Tests are conducted on hunter-harvested deer at check stations in the other CWD counties. The DNR discontinued the check station system elsewhere in the state and replaced it with a call-in reporting format.

Shelton said it was too late to mandate check station reporting this season in LaSalle County, but he’ll explore the possibilities of setting up a location for volunteer testing there.

Grundy County, which borders LaSalle, might also be included in the volunteer program.

“The timing of this doesn’t lend itself real well for sudden changes,” Shelton said.

LaSalle and Grundy counties might also be added to the special CWD season in January so the DNR can test more deer.