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Bison in brucellosis test.

Brucellosis Vaccine for Cattle May Also Work for Bison

By Linda Cooke
November 4, 1997

A new vaccine against brucellosis in cattle shows promise for protecting bison against the contagious disease. Bison and elk are the last major sources of brucellosis in the United States.

The disease is caused by the bacterium Brucella abortus. In beef and dairy cattle, it causes abortions, lessens fertility and reduces milk production, costing the U.S. beef and dairy industry about $30 million annually.

Scientists with USDA’s Agricultural Research Service have been checking the newest official vaccine containing B. abortus strain RB51 for its effectiveness and safety in bison. In an experiment at ARS’ National Animal Disease Center in Ames, Iowa, scientists vaccinated 10 female bison calves donated by the U.S. Fish and Wildlife Service.

The vaccinated bisons’ immune response was comparable to that of cattle vaccinated with RB51. In earlier studies, ARS scientists demonstrated that RB51 protects cattle against brucellosis and that vaccinated cattle don’t show false signs of infection in blood tests. Based on the ARS studies, USDA’s Animal and Plant Health Inspection Service (APHIS) conditionally approved the new vaccine for use in cattle.

None of the RB51-vaccinated bison shed the live bacterium into the environment. This demonstrates the biosafety of the vaccine in bison and helps prevent accidental exposure to other wildlife. Moose, for instance, can die if infected with virulent strains of B. abortus. ARS and APHIS researchers are monitoring bison in Yellowstone National Park to study how brucellosis is transmitted among free-living bison and elk.

Humans can get brucellosis from handling infected carcasses at slaughter or from infected cows during calving. In humans, the disease is called undulant fever and produces severe flu-like symptoms. Consumption of unpasteurized milk and dairy products can also cause undulant fever.

The November issue of Agricultural Research, ARS’ monthly magazine, contains an article about the brucellosis research. The article also is on the World Wide Web at:


Scientific contact: Steven C. Olsen, USDA-ARS, Zoonotic Diseases Research Unit, National Animal Disease Center, Ames, Iowa, phone: (515) 239-8393,