Second Brucellois Case in Idaho

By Carol Ryan Dumas
Capital Press
December 8, 2009

Tests have confirmed a second animal positive for brucellosis in an eastern Idaho herd.

The disease is highly infectious and can cause cattle to abort.

Idaho State Veterinarian Bill Barton said all animals in the herd have been tested and most results are back.

The department and the industry take a brucellosis finding seriously as another finding in a separate herd would cause the state to lose its brucellosis-free status, wreaking havoc on cattlemen's ability to market their animals.

The industry lost its brucellosis-free status in January 2006.

Aggressive action saw the state regain its status in July 2007.

Although another animal was found to be suspect for the disease discovered last week, further testing confirmed it was not infected.

The two positive animals were found in a 600 head herd based in Rigby and assembled over the last couple of years, Barton said.

Further testing was needed on the first animal, a 15-year-old cow, because it was vaccinated with an older vaccine that can show a false positive with the standard blood test.

"The vaccine is the best we have, but at 15 years of age, immunity is waning a little bit," Barton said.

The older strain 19 vaccine has about the same efficacy as the newer

RB15 vaccine, but where it's been used, epidemiologist must take a milk sample and culture the tissue for a definitive diagnosis.

All animals in the herd had been vaccinated as required by the state, Barton said.

The first positive finding came as a result of another animal from the herd testing suspect at slaughter.

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