Oklahoma scientists work on new brucellosis vaccine

OKLAHOMA CITY (AP) - Oklahoma State University researchers working to rid the world of brucellosis say they would like nothing more than to put an end to the disease - not to mention reducing one less option during a war.

John Wyckoff is the project leader for a research group in the OSU College of Veterinary Medicine developing a vaccine for brucellosis, one of the most serious diseases of livestock and a potential agent in biological weapons.

In livestock, the brucellosis bacteria causes cows to abort, makes calves sick, decreases milk production and interrupts breeding cycles.

"Each aborted fetus has enough bacteria to infect the entire herd of cattle in the U.S.," he said.

Through eradication efforts in the United States, only six affected herds of cattle exist in Texas, Missouri and South Dakota, down from 124,000 nationwide in 1956. The state and federal eradication programs included livestock quarantines, costly vaccinations and widespread animal tests.

But Wyckoff said the disease still affects tens of thousands of livestock and people worldwide.

Current vaccines contain live bacteria that can be infectious; some veterinarians have caught undulant fever, the human form of the disease, from contact with the medicine. Wyckoff's team is looking to create a vaccine with fewer drawbacks.

"Instead of trying to work with a live vaccine, we are trying to come up with one or two components of the bacteria that, although they are dead, will still stimulate very strong immunity," he said.

The project is three to four years away from trial experiments on cattle.

Wyckoff said the disease is still a problem in American cattle, but not to the degree of people and animals in Third World nations.

He said the disease is ingested worldwide mainly by eating unpasteurized dairy products such as soft cheeses. Wyckoff said bacteria can live up to 18 months in such foods.

Brian Espe, area veterinarian for the U.S. Department of Agriculture, said Wyckoff's work is still needed even though the disease is only found in a small number of the nation's cattle herds.

"Fortunately, we've about got brucellosis eliminated from the U.S. after a span of 50 years, " he said. "But worldwide, brucellosis is a still a problem."

Espe said the presence of free-ranging bison in Yellowstone and Grand Teton national parks threaten the brucellosis status of the surrounding states free of the disease.

"Sooner of later, if the United States is considered free of brucellosis, bison will need to be free in that population," he said.

Also wild elk, often infected when they gather for winter feeding, can potentially spread the disease. Espe said efforts to discontinue the unnatural feeding and congregation of herds are being considered.