LANDER - Wyoming's chief wildlife manager said he believes it's currently impossible to purge brucellosis from bison and elk in the Yellowstone ecosystem, indicating that the federal policy of eradicating the disease is not realistic.

Brucellosis is endemic to the elk and bison populations in the Yellowstone region, said Terry Cleveland, director of the Wyoming Game and Fish Department, and the tools don't yet exist to eliminate the disease from wildlife.

"It's my personal belief that the ultimate solution for the livestock industry would be researching and developing a vaccine that's 100 percent effective in cattle," Cleveland said.

That, coupled with a continuing effort to reduce opportunities for contact between elk and livestock during the four months when the disease is transmitted, seems the most reasonable strategy at present, he said.

Brucellosis has once again been found in a Wyoming cattle herd, and if it pops up in another herd owned by a separate rancher within two years, the Cowboy State will once again lose its federal "brucellosis-free" market status, as it did in 2004. The state regained it in 2006.

Brucellosis can raise the cost of doing business for some stockgrowers, but it poses no real threat to wildlife in the Yellowstone region, said Brandon Scurlock, a brucellosis expert with the Game and Fish Department.

The bacterial infection has been known to cause an elk cow, for example, to abort her first pregnancy after she's contracted the disease, but she'll generally be able to reproduce normally thereafter, he said.

"Elk have lived with this disease since the 1930s," Scurlock said. "From a population standpoint, it has very little effect on wildlife."

Along with causing hoofed animals to abort, brucellosis can infect humans, manifesting as a disease called undulant fever.

In 1934, the federal government made eradication of the disease in the United States a national policy. At the time, brucellosis posed a serious human health risk. Because most people now drink pasteurized milk, however, the risk of humans contracting the disease in the United States is almost nonexistent, Scurlock said, outside of those who work directly with infected animals, or with fetuses aborted by infected animals.

It is not dangerous to eat the meat of animals infected with brucellosis, as long as it is cooked.

Vaccinate wild herds?

Wildlife advocates tend to say brucellosis is a livestock problem, and stockgrowers tend to say it's a wildlife problem.

The U.S. Department of Agriculture considers the Yellowstone area to be one of the last reservoirs of brucellosis in the country, and if the disease were eliminated there, it would mark the realization of the 74-year federal policy of eradicating the disease.

But the act of attempting to vaccinate a whole ecosystem's elk and bison could mean the loss of "wildness" in the herds, and would require a quasi-domestication of the animals, a spokeswoman with the Jackson Hole Conservation Alliance said.

Brucellosis has been all but eliminated from America's livestock, but transmission from wildlife to cattle still occurs, intermittently, as in a recent flare-up in Montana, and possibly again in Sublette County, where 29 head of cattle from the same herd are now confirmed to have been infected.

Authorities have yet to determine whether the Daniel-are herd contracted the disease from elk, or from another cattle herd.

When the disease is discovered in livestock, the stockgrower must slaughter all of the rest of his animals that are capable of breeding - whether or not the cows or bulls have been infected themselves - or the entire state loses its "brucellosis-free" status.

This market status has implications for ranchers because it requires them to do more testing on their herds and can limit interstate cattle trading, said Jim Magagna, executive vice president of the Wyoming Stock Growers Association.

Magagna said he agrees with Cleveland that it's currently not possible to eradicate the disease from elk and bison in the Yellowstone region, but he believes it's also an important goal to come up with the tools to make that eradication a reality through "extensive, significant research."

It would be a mistake, Magagna said, to allow the disease to go unchecked in wildlife, because any vaccine for brucellosis, no matter how effective, could be overwhelmed by high enough concentrations of the brucellosis bacteria.

"We cannot afford to take off the table the idea of developing a vaccine for wildlife, along with a more viable delivery system," Magagna said.

And even though the disease is no longer a big human health issue in this country, other parts of the nation have eradicated it in their livestock and wildlife, he said, and "they don't want it back."

If Wyoming stockgrowers were to unilaterally decide that brucellosis is "not a big deal," and agree to live with it at certain levels in their herds, the economic effects would be "devastating," Magagna said, because other states would boycott Wyoming cattle and beef.

Pressure on wildlife?

Louise Lasley, public lands director for the Jackson Hole Conservation Alliance, said the U.S. Department of Agriculture's aggressive stance toward the disease in the Yellowstone region - which is echoed by the U.S. Cattlemen's Association - is "disturbing."

She said she fears the agency will call for more vaccination, coupled with reductions of elk and bison numbers, following the latest brucellosis outbreaks in Montana and Wyoming cattle.

Last week the U.S. Cattlemen's Association called upon the Department of the Interior and the USDA to "reduce bison and elk numbers within the Yellowstone National Park - and to work with affected states to undertake an aggressive long-term brucellosis eradication program in the Greater Yellowstone Area."

But Lasley said that effort has been going on for years, and it hasn't worked.

"It seems like an awful lot of resources are being frittered away on a plan to vaccinate wild animals, when it would be much, much easier to come up with better vaccines, fencing, haystacks and feedlines for cattle," Lasley said.

The number of cattle directly affected by the disease is significantly lower than that of bison and elk, so it seems a bit absurd to try to control the disease in the larger, wild population, rather than focusing on the domesticated animals, she said.

"If you look at the sheer numbers, the approach is irresponsible," Lasley said. "We're basically trying to domesticate wildlife herds for the purposes of somehow being able to inoculate them. It's disturbing from a wildlife perspective because we're losing the wildness of the herds."

Lasley said she takes issue with claims made by the livestock industry that the presence of the disease in Yellowstone-area wildlife makes the cattle in this region less attractive to buyers.

Buyers know what they're getting when they buy Wyoming cattle, she said.

"All the cows in this area can't be sold without being tested," Lasley said. "So if somebody from another state is truly concerned about bringing brucellosis into their herd, they know they're less likely to get it from cattle from this area than elsewhere. If they buy their cattle from somewhere else, they're just betting those cows don't have it, but they can't be sure."

Magagna said when a state loses its "brucellosis-free" status, all of the other states develop their own rules regarding cattle from the "infected" state. While it might be possible to sell tested cattle in some states, others can chose to exclude cattle from the infected state altogether.

Environment reporter Chris Merrill can be reached at chris.merrill@trib.com or at (307) 267-6722.