States attack deadly deer disease. (On First Reading).

In an effort to contain the chronic wasting disease (CWD) afflicting deer and elk across the United States, thousands of captive elk have been killed in Colorado and other states. Wisconsin set a special summer season when hunters were asked to kill 25,000 deer in a 389-square-mile eradication zone in the southern part of the state to help thin the herds.

Wild deer and elk and animals in some captive herds in Colorado, Kansas, Minnesota, Montana, Nebraska, New Mexico, Oklahoma and South Dakota, as well as Alberta and Saskatchewan, have been diagnosed with the disease.

CWD destroys the brains of deer, elk, moose and caribou; the animals become emaciated, act abnormally, lose coordination and die. How the disease is transmitted is unknown.

"There is no vaccine, and it is incurable once an animal contracts it," says Brent Manning, director of the Illinois Department of Natural Resources.

CWD is a one of the transmissible spongiform encephalopathies diseases that include Creutzfeldt-Jakob in humans and bovine spongiform encephalopathy (mad cow disease). To date, it does not appear that CWD can be transmitted to humans.

Despite efforts to reduce exposure to sick animals, wild deer in Illinois and captive elk in Minnesota tested positive for the disease this fall. Several states are testing samples donated by hunters to determine how much farther the disease has spread.

The Wisconsin Legislature passed legislation in a special session last May authorizing the Department of Natural Resources to test for the disease.

Colorado and Wisconsin have $6 million from the U.S. Department of Agriculture, which has developed a model surveillance and monitoring program, to fight CWD.

"The best way to combat CWD is to test every animal," says Scott Salonek, an elk farmer from Dayton, Minnesota.

Deer hunting is big business for states. Illinois estimates hunters contribute $400 million to the economy, while Minnesota expects 450,000 hunters to add hundreds of millions of dollars to the state's economy. Michigan is concerned about CWD crossing its borders where 800,000 hunters add 5500 million to the state coffers.