The angry e-mail and telephone messages just keep pouring into Bureau of Land Management offices.

How could they? How could the government sanction the killing of wild horses?"To some people, especially those in Europe, wild horses are the epitome of the romantic image of the Old West," said BLM director Pat Shea during a recent trip to the Uinta Basin where horses infected with infectious anemia roam. "You wouldn't believe the emotions that are generated by wild horses."

But emotion rarely leads to sound management policy, he said, and the bottom line is that the contagious horse disease, better known as swamp fever, now threat-ens a $293 million domestic horse industry in Utah. And without quick intervention, the disease could easily spill across the eastern Utah border into Colorado.

The only option to eradicate the deadly disease is to round up all horses, domestic and wild, in the Uinta Basin and eliminate the infected horses.

"Euthanasia is not only the law, it's the only option with a disease of this nature, in a situation as serious as we have in the Uinta Basin," said Vernal District BLM manager Dave Howell.

Fueled by worldwide media reports, many of them containing erroneous information about the impending slaughter of the infected horses, the BLM has been raked with criticism from horse lovers and animal rights advocates.

Under provisions of the federal Wild Horse and Burro Act, the BLM has taken the lead on the eradication effort. This week, helicopters will be used to round up as many as 500 wild horses on public lands in the Uinta Basin. Ute tribal leaders have also ordered the round-up 150 to 200 horses on adjacent tribal lands that are owned by tribal members.

The state veterinarian's staff, working with both the tribe and the BLM, will then draw blood from the horses. Infected horses will be killed, and the remaining horses will be released.

The BLM is putting a positive spin on the effort. "Our whole thrust here is a rescue mission for the wild horses," Howell said. "Those wild horses that are healthy, we want to make sure they remain healthy and are separated from infected animals."

The Utes are cooperating fully in the endeavor, but they also gave Shea an earful about the failure of the BLM and the Utah Department of Agriculture to work more closely with the tribe on the issue. They were particularly critical of press releases issued by both entities that contained erroneous information they believed cast the tribe in an unfavorable light.

For example, media reports characterized the infection as afflicting Utah's wild horse population. The Utes maintain the horses are not wild but instead comprise a free-roaming herd that belongs to one particular tribal member. That tribal member worked closely with the Department of Agriculture to test the animals in March after they had been rounded up from tribal lands, not public lands administered by the BLM.

They also pointed out there is no evidence, at least not yet, that wild horse populations are infected with the disease. The only confirmed cases of the disease this year are from the private herd tested last March.

To BLM managers in Vernal, the tribe's concerns are a disagreement over semantics. According to Howell, all free-roaming horses on public lands are considered wild. Free-roaming horses on tribal lands are considered domestic livestock by the tribe, but once they wander off the reservation, the BLM then considers them to be wild horses.

Given the highly contagious nature of the disease, free-roaming domestic horses could easily have passed the disease to wild herds. That prompted the BLM's "rescue mission."

"We are outraged and shocked," said Holly Hazard of the Washington-based Doris Day Animal League. "This is not what we were led to believe they would do. They made promises to us that they would not do this during foaling season," which runs through July.

Tony Moore, spokeswoman for the Wild Horse and Burro Freedom Alliance in Fruita, Colo., said the roundup "could be a real disaster, and some of our members feel that (the roundups) are cruelty in the extreme."

Utah BLM spokesman Don Banks said the roundups will be done at a slower-than-usual pace to allow foals to keep up with their mothers. Strategically placed traps will minimize the distance horses have to travel.

"We're aware of the foaling situation. Our contractors will be taking special precautions to ensure we do everything possible to minimize stress on the herds, especially foals with mares," Banks said.

The disease was first detected in March during routine testing of about 200 horses owned by a Ute tribal member. Some 29 horses were found to have the disease. Statewide, about 7,000 horses are tested for the disease every year, but only one to three animals a year test positive.

"A 14 percent ratio (of infection) is unprecedented in Utah," said Larry Lewis, spokesman for the Utah Department of Agriculture. "We are trying to figure out why. It may be because of the excess moisture this year. There are more breeding grounds for mosquitoes and horse flies (which carry the dis-ease)."

Wild horses are typically not tested for the disease unless they are captured as part of the BLM's wild horse adoption program. Over the past 20 years, thousands of horses on public lands have been tested. Only one wild horse has tested positive for the disease; that occurred about two years ago.