RESEARCH REPORT
Study shows bison can give cattle brucellosis

YELLOWSTONE NATIONAL PARK (AP) - Livestock research from up to 30 years ago suggests that cattle in the greater Yellowstone area have caught brucellosis from bison and elk and not from other cattle.

Other research shows that elk and bison can transmit the disease to cattle under laboratory conditions, according to a report released by the Greater Yellowstone Interagency Brucellosis Committee last week.

Brucellosis can cause livestock to abort their calves. The disease rarely causes undulant fever in human beings.

Many elk and bison in and around Yellowstone National Park are believed to be infected with brucellosis. Fear that wildlife could spread the disease to livestock prompted Montana officials to kill nearly 1,100 bison two years ago.

The committee studied six cases of cattle brucellosis described by U.S. Department of the Agriculture and Wyoming Livestock Board officials in the 1960s and 1980s. The state and federal officials concluded that wild elk or bison were the probable source of infection in all six cases.

The brucellosis committee agrees with those conclusions, said Tom Thorne, a Wyoming Game and Fish Department official who sits on the committee.

"Everybody agrees it's rare. ... It's remote, but there's no question (the transmission from wildlife to cattle) can happen," he said.

Two of the brucellosis transmissions from wildlife to cattle occurred since Wyoming was classified brucellosis-free in 1985.

Thorne said that by issuing the report, the committee is "accepting the fact that there's a very real possibility" that wildlife can transmit brucellosis to domestic cattle.

"I would hope that by adopting this paper that the committee can put this argument behind it, in terms of 'can it transmit or can it not transmit?' " he said. "They're going to accept it as a true possibility and (then) deal with brucellosis in that sense."

State and federal officials have long contended that the possibility of cattle catching the disease from wildlife is very low.

Many bison advocates say that agriculture interests have never been able to prove that free-ranging wildlife can transmit the disease to cattle.

The controversy is the result in large part of the limited amount of information upon which to make predictions and management decisions, the report said.

"However, extensive epidemiological evidence, including complete testing of herds associated with the (infected herd), ruled out domestic livestock as the source (of the brucellosis infections)," the report said.

In addition, Texas A&M University researchers have shown that bison infected with brucellosis could transmit the disease to susceptible cattle, according to the report.

Controlled Game and Fish Department studies have meanwhile demonstrated that brucellosis causes spontaneous abortion in elk, and that under confined conditions the disease can be transmitted from infected elk to susceptible cattle, the report said.

The disease is found in elk on the National Elk Refuge and in elk feeding on state feed grounds in northwestern Wyoming. The Game and Fish Department has vaccinated more than 35,000 elk at 22 of the state's 23 feed grounds.