MADISON, Wis. -- The state's multimillion-dollar efforts to slow chronic wasting disease in its deer herd aren't working, a state audit released Thursday says.

The Legislative Audit Bureau's report found that the Department of Natural Resources had spent nearly $27 million battling the disease since it surfaced in Wisconsin in 2002.

The agency has been working to thin the deer herd in areas where the disease has been found by lengthening hunting seasons, requiring hunters to shoot a doe before a buck, banning feeding deer in 26 counties and offering rewards and cheap permits for hunters, as well as using sharpshooters to kill more deer.

Despite those measures, the audit found the estimated number of deer in chronic wasting disease zones has increased from 26 deer per square mile in 2002 to 38 in 2005.

"Compared to other states in which CWD has been identified, Wisconsin has taken an aggressive approach to addressing the disease," the audit said. "That approach also has been more costly, but it has not been effective to date."

Chronic wasting disease produces microscopic holes in animals' brain tissue, causing weight loss, tremors, strange behavior and, eventually, death.

The disease, which has been found in deer in 14 states, is in the same family of fatal brain illnesses as mad cow disease and its human equivalent. There is no evidence, however, that people have ever caught chronic wasting disease from infected deer or elk.

In a letter to state auditor Janice Mueller responding to the report, DNR Secretary Scott Hassett conceded CWD can't be eradicated in the near future.

"Wisconsin received a lot of advice, but no one handed us a road map," Hassett wrote. He said the agency would consult the public for suggestions.

The disease is also found in elk and deer populations in a number of states around the West. Earlier this year, Colorado wildlife officials said killing deer and elk to contain the spread of chronic wasting disease hadn't worked. Animal activists, elected officials and some scientists had questioned the approach.