For Immediate Release
July 24, 2008
CONTACT: Steve Merritt
Public Information Officer
Montana Department of Livestock
406-444-9431
DNA testing points to elk as likely source of brucellosis
Fingerprinting tests, or genotyping, from the brucellosis-infected cow found in Paradise Valley earlier this year have identified elk as the most likely source of the disease.
According to the report issued by the National Veterinary Services Laboratories (NVSL) in Ames, Iowa, "Genotyping results …indicate that the Brucella abortus strain recovered from the adult cow in Montana appears to be similar to strains recovered from bison and elk in the Greater Yellowstone Area."
"The genetic analysis is consistent with other epidemiological information that suggests the transmission of brucellosis from elk to cattle," said Dr. Martin Zaluski, state veterinarian. "We've now had two cases of the disease in two years, and no contact with bison in either case. It supports our conclusion that elk were the source in both cases."
Zaluski said the information is a "crucial" piece of evidence that should pave the way for future efforts to manage the risk of brucellosis transmission from wildlife to cattle.
"The evidence supports the concept of interspecies transmission and shows that brucellosis must be a consideration in elk management in the Greater Yellowstone area," Zaluski said.
The Montana Board of Livestock at its July 22 meeting passed a motion directing Zaluski and the Department of Livestock to establish a task force that can evaluate the problem and develop potential solutions.
The motion reads, "Since there is compelling evidence that brucellosis can be transmitted to cattle from wildlife, the BOL directs the DOL to work with Fish, Wildlife and Parks to jointly set up a task force that includes both livestock producers and sportsmen to help design both short- and long-term wildlife disease management policies."
"A task force with a strong mission statement to keep it focused will be an immensely valuable tool," Zaluski said.
Brucellosis is a bacterial disease that causes pregnant cows to abort, and also causes decreased milk production, weight loss, infertility and lameness. A zoonotic disease, it can be passed to humans through unpasteurized dairy products and contact with birthing fluids from an infected animal.
Montana had been brucellosis free since 1985, but the disease was discovered in a Bridger cattle herd in May of 2007. That outbreak was traced to a herd in Emigrant, located just north of Yellowstone National Park. This year's case, which was identified in late May and confirmed on June 9, was the second found in Montana within the last 12 months; as such, it is expected that USDA will revoke Montana’s Brucellosis Class Free status. Brucellosis was also found this summer in Wyoming.
Fingerprinting, or genotyping, is a way to determine the genetic makeup of an organism or a group of organisms. The process used in Montana's brucellosis investigation is called variable number tandem repeat (VTNR), which is especially useful in genetic and biological research, forensic crime investigations, paternity suits, and to study genetic diversity and breeding patterns of wild or domestic animals.
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