State and federal agriculture officials hope by midweek to finish euthanizing about 350 elk exposed to chronic wasting disease on a ranch near Del Norte.

Crews have worked continuously since Friday to kill the elk on the Rancho Anta Grande elk ranch after a cow elk purchased from a ranch near Stoneham tested positive for the fatal disease.

After the elk are killed, their heads are removed so brain stems, lymph nodes and tonsils can be checked for the disease. The carcasses are incinerated in a pit by an air curtain incinerator capable of producing temperatures over 2,500-degrees Fahrenheit.

That heat destroys the mutant protein, called a prion, that is believed to cause the disease that leaves microscopic holes in the brains of infected animals.

There are no tests to determine if a living animal has the disease, so any herd that comes in contact with an infected animal has to be destroyed to ensure the disease doesn't spread to other livestock or wildlife.

Chronic Wasting Disease in deer and elk is related to mad cow disease in cattle, scrapie in sheep and Creutzfeldt-Jakob disease in humans. All belong to a family of illnesses called transmissible spongiform encephalopathies, or TSEs.

These diseases attack the brain and central nervous system, destroying healthy tissue. The word "spongiform" describes the spongelike condition of brain tissue seen in victims.

Unlike mad cow, there is no evidence eating infected deer or elk can lead to death in humans. Wildlife and health officials, however, advise hunters who kill animals in an area where the diseases has been found in the wild to submit the heads of animals killed for testing before consuming the meat.

The disease was first discovered in 1967 in research pens near Fort Collins. It later was found in wild animals between Fort Collins and Wheatland, Wyo.

Today the area extends from Boulder to Wyoming, Fort Collins to Nebraska following the South Platte River valley.

The state veterinarian hopes to finish in Del Norte by mid-week, Linh Truong, spokeswoman for the Colorado Department of Agriculture, said Monday.

"As soon as they finish, they will be moving on to Stoneham where there are six ranches and about 850 animals that will be euthanized," Truong said.

Contact Gary Gerhardt at (303) 892-5202 or gerhardtg@RockyMountainNews.com.