September 25, 2002 Denver Post by Theo Stein
A sick elk euthanized by a game warden in northwest Colorado has
tested positive for chronic wasting disease - a discovery that
threatens to upend assumptions about the spread of the fatal brain
It's the first time a wild elk has come down with the disease on the state's hunting-dependent Western Slope.
And with thousands of hunter-killed deer and elk samples headed to the Colorado Division of Wildlife's lab this fall, biologists are steeling themselves for more bad news. 'Based on the way that things are shaping up now, it's going to be a long winter,' said Mike Miller, the division's veterinarian and a leading national CWD researcher. 'I guess it could be worse, but I just can't figure out how.'
The adult cow elk was killed Sept. 6 along a county road 10 miles north of Hayden after residents notified local wildlife managers that it was acting strange.
It was found about 30 miles north of a hunting ranch near Hamilton where 10 infected mule deer were killed last spring, but Miller said there's no way to know whether the case is part of the same outbreak, or the leading edge of a new one.
'One thing we've learned is that because of the disease's long incubation period, we're always going to be a step behind,' he said. 'Either it's been around a lot longer, it moves around in ways we're unaware of, or it's more of a spontaneous, natural phenomenon than we ever wanted to believe.'
Hunting guide Ty Stewart, who has stalked elk and deer in northern Routt County for most of his 34 years, thinks the disease arrived years ago.
'Sometimes you see animals and you don't know what's wrong with them, but they have that skin-and-bones look,' he said. 'I think they'll probably find it everywhere there's a good population of deer or elk.'
Even in the endemic area of northeastern Colorado where it has existed for at least four decades, CWD is relatively uncommon. The DOW estimates that between 5 and 15 percent of mule deer and about 1 percent of elk are infected in an 8,000-acre triangle extending from Chatfield Reservoir north to Wyoming and east along the South Platte to Nebraska.
So the appearance of an infected elk in northern Routt County almost guarantees there are other sick animals out there, Miller said.
The disease, which infects mule deer, white-tailed deer and elk, is believed to be caused by an abnormal form of a natural brain protein. Infected animals may show no symptoms during a one- to five- year incubation period, but eventually turn into slobbering, wobbling zombies as accumulations of the mutant protein eat spongy holes in their brains.
No human cases of CWD have ever been documented, but its close relationship to mad cow disease, which has killed 120 Europeans, has caused health officials to urge hunters not to eat potentially infected meat.
Once thought to be confined to Colorado and Wyoming, CWD has erupted in captive elk and wild deer herds all across the continental midsection during the last seven years.
"I think we're just seeing the first chapters with this disease," said Bob Saile, a Denver-based editor for Field and Stream.