State agriculture officials have destroyed about 330 elk on a Del Norte ranch in the San Luis Valley -- where a cow elk was diagnosed with chronic wasting disease -- and will move next to a ranch in northern Colorado to kill 200 elk there.

Because there are no live tests to detect the contagious and fatal disease, all of the elk that came in contact with the cow had to be destroyed.

In addition, three trophy bulls shot by clients at the Trophy Mountain Ranch near Cowdrey in North Park tested positive for CWD. The remaining herd numbers more than 200 animals.

The Del Norte herd was incinerated in pits with an air-curtain furnace that raises temperatures to between 1,500 and 2,500 degrees Fahrenheit and is capable of destroying the mutant protein that causes the disease.

Linh Truong, spokeswoman for the Colorado Department of Agriculture, said Wednesday that samples of brain stems, lymph nodes and tonsils were taken from the animals to be tested for the disease.

Once that's completed, she said, State Veternarian Wayne Cunningham will make a decision about what to do with the ashes.

"There were 15 to 20 people that worked in bitter cold and strong winds at Del Norte since last week and they are going home to get some rest, then move the equipment to Cowdrey next week," Truong said.

CWD in deer and elk, mad cow disease in cattle, scrapie in sheep and Creutzfeldt-Jakob disease, or CJD, in humans all belong to a family of illnesses called transmissible spongiform encephalopathies, or TSEs.

These disease agents attack the brain and central nervous system, destroying healthy tissue.