April 11, 2002 The Denver Post by Theo SteinState agriculture officials said Wednesday that 32 elk infected with chronic wasting disease were discovered during a disease-control program that ended with the slaughter of 1,500 elk this winter.
Officials also found that an additional 17 elk contracted the fatal brain disease during an outbreak that smoldered for years on a Stoneham ranch until veterinarians realized the extent of the problem in September.
All told, 1,724 Colorado elk have been destroyed since last fall as authorities have fought to contain the outbreak, agriculture department spokeswoman Linh Truong said.
Animals killed for testing
Since there's no live test for the disease in elk, animals must be killed and their brains tested for infection.
Of the 49 confirmed cases, four were in Nebraska and one in Kansas. The 44 Colorado cases were found on nine ranches. Agriculture officials said only 2.5 percent of the herds were infected in the largest outbreak in U.S. history.
Twenty-nine of the infected animals were found at Elk Echo Ranch in Stoneham, which officials believe was the source of the outbreak. Another 20 elk either were infected at Elk Echo before being moved to other ranches, or they contracted the disease from infected elk that were added to their herds.
Truong said officials are still trying to figure out why the state's chronic wasting disease surveillance program, which started in 1998, didn't identify the problem earlier.
Regulations require ranchers to submit the fresh brains of all dead adult elk for lab analysis.
'It's too early to pinpoint where things went wrong,' she said. 'The surveillance system worked because we caught all the positive animals. Whether it worked the best it could have is something we're going to look into. And the lessons we learn from these past nine months will be used to improve the system in place.'
Infection as early as '92
The first hint of a problem appeared in 1997, when a cow bought from Elk Echo died on a Dalton, Neb., ranch. In a report last fall, state veterinarian Wayne Cunningham said Elk Echo may have been infected as early as 1992.
Elk Echo was first quarantined because of the Nebraska cases in June 1999. But the quarantine was lifted a month later after an examination of the herd showed none of the elk had symptoms of the long-incubating disease.
Elk Echo was again quarantined in April 2000 after a suspicious elk death at the ranch one month earlier. Three spinoff ranches were quarantined in September 2001 after an Elk Echo animal died of CWD in the San Luis Valley.
Researchers believe chronic wasting disease is caused by abnormally folded, naturally occuring brain proteins, which recruit other proteins to adopt their malignant shape. Tiny holes form in parts of the brain as the disease progresses, leading to emaciation, slobbering, poor coordination and death.
Even though chronic wasting disease is related to mad cow disease, there is no evidence that it can infect humans.
First discovered at a Colorado Division of Wildlife research facility in 1967, the disease was found to infect about 5 percent of wild deer across a 15,000-square-mile area of northeastern Colorado, southern Wyoming and the Nebraska panhandle. This year, tests have confirmed chronic wasting disease in wild herds in South Dakota, Nebraska, Wisconsin and Saskatchewan.