By CAROL RYAN DUMAS
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.
"All animals at the slaughter plant are inspected with a blood test," Barton said.
If one shows up positive or suspect, all animals in the herd are tested.
"We are continuing our investigation as rapidly as possible," he said.
That entails not only testing the herd, which is now complete, but tracing animals to their herd of origin and testing those herds.
Barton has confirmed that all animals that left the herd were sold to slaughter.
That's good news in regard to any possible forward infection from the herd. The question now is whether the herds where the animals originated are infected. Barton is more of the mind that the infection came from wild elk or bison that the herd came in contact with.
Brucellosis is prevalent in those wild animals in the Greater Yellowstone Area and the herd summers in the Teton Basin.
Cattlemen in the West are anxiously awaiting Idaho's testing results.
Brucellosis is one of a handful of bovine diseases that cause concerns when it comes to moving cattle from state to state, said Matt Byrne, vice president of the California Cattlemen's Association.
California is brucellosis-free and cattle producers want it to stay that way, he said.
"Hopefully we'll find that it is a localized incident and won't have an impact on California," he said.
California has had its own infectious disease troubles with tuberculosis, which has infected eight cows in the state since January 2008, according to the state's Department of Food and Agriculture. About 419,000 head of cattle have been TB tested, two herds depopulated and more than 8,000 cattle killed as part of an ongoing investigation, the CDFA reports.
The USDA last year stripped California of its tuberculosis-free status, causing cattle to have to be tested before they leave the state.
"I think having those kinds of diseases of special concern that pop up anywhere in the West is always a bit of an issue," Byrne said.
Capital Press reporter Tim Hearden contributed to this report.