Brucellosis possible in Park County
Meeteetse – Blood samples from four Meeteetse-area cattle originating from one herd recently reacted to tests for brucellosis. Ten neighboring herds are under quarantine and are being tested for the disease.
The Wyoming Livestock Board (WLSB) is working with USDA APHIS to test up to 3,000 head of cattle from herds that may have co-mingled with the suspect herd, as well as herds that share a boundary. Wyoming State Veterinarian Jim Logan says reactors on blood tests do not absolutely prove that cattle are infected with brucellosis; however, the reactors in these four cattle were very strong, indicating a high likelihood of infection.
According to Logan, on Oct. 25 blood tests reacted to brucellosis for three of 16 cull cows sold for slaughter three days earlier through the Worland Livestock Auction. The Wyoming State Vet Lab notified the Wyoming State Veterinarian, and the WLSB launched an epidemiologic investigation. The reactive cattle were quarantined, and Wyoming Assistant State Veterinarian Bob Meyer took blood and tissue samples for further testing. As of press time, they were awaiting the results, which can take two weeks or longer.
Meanwhile, the WLSB notified the owners of the suspect herd and initiated testing of cattle over one year of age, with the exception of steers and spayed heifers, which cannot transmit the disease. One additional cow from the same ranch tested positive, and she was isolated from the herd to undergo further testing.
“The initial blood tests work well, but they are sensitive, and occasionally give a false positive. That’s why we follow up with further blood tests and tissue samples, and send them to the National Vet Services Lab in Ames, Iowa for a complete diagnostic work up,” explains Logan.
Owners of the suspect herd promptly notified their neighbors. “The owner wished his neighbors to hear the news from him first,” says Meyer.
Cattle that comingled with the suspect herd, or that share a boundary, are considered a contact herd and are at risk for transmission of the disease. The WLSB sent letters to the owners of suspected contact herds, and owners of all currently known contact herds have been notified.
Meyer conducted interviews with the suspected contact herd owners, eliminating some herds that did not have sufficient contact and adding others. As of press time, the suspect herd and five contact herds have completed testing. The results of two contact herds have come back as negative. The WLSB awaits the results of the other tests, and continues to test the remaining contact herds.
Over 80 people – mostly area ranchers – packed into the Meeteetse Conservation District building Nov. 2 for an informational meeting hosted by the WLSB.
“The producers have been very cooperative,” comments Meyer. “They have the attitude of, ‘If our herd has the disease, let’s find it and stop it.’”
Brucellosis is a highly contagious bacterial disease that can cause cattle, elk and bison to abort their calves, and it can seriously affect humans as undulant fever. The disease was first discovered in the 1880s and the USDA initiated a national brucellosis eradication program in 1934.
“This is not a food safety issue, as long as proper cooking takes place,” notes Logan. USDA guidelines for cooking and storing beef can be found at fsis.usda.gov/factsheets/beef_from_farm_to_table/index.asp.
The WLSB is working to track the source of the brucellosis occurrence. Thousands of elk populate the Park County region on private and public land, however, Logan says the disease could have been introduced by cattle brought into the area.
If producers discover an elk fetus, they are encouraged to avoid contact, secure a tarp over the site and contact the WLSB immediately. The disease can be transferred through a fetus, placenta and fluids. The WLSB cautions producers to wear appropriate gloves and clothing when handling these potentially contaminated substances in cattle, elk or bison.
The Wyoming Game & Fish Department (WGFD) encourages area producers to obtain free elk brucellosis test kits from the local WGFD office and request that elk hunters on their ranches immediately test harvested animals and promptly send in the sample. Currently only about half of the elk blood tests the WGFD receives are viable for testing, and the agency plans to test more elk from Park County to determine the scope of the disease.
Wyoming, Idaho and Montana have all lost and regained brucellosis-free status in recent years. A Pinedale herd tested positive in December 2004, with evidence leading to transmission from elk on a nearby feed ground. Further testing identified positive herds in Teton County, and the USDA withdrew Wyoming’s brucellosis-free status, causing many cattle to be tested and certified brucellosis-free before they could leave the state. The Wyoming State Brucellosis Coordination Team was created and presented 28 recommendations to the Governor and legislators before Wyoming regained brucellosis-free status in September 2006. Cattle from a Sublette County herd tested positive in 2008, and the producer destroyed his herd so Wyoming could retain its brucellosis-free status.
The USDA is reviewing its approach to brucellosis management, and is managing the disease more on a case-by-case basis, rather than focusing on state status.
“As long as the state is fulfilling all the quarantine and testing requirements on any suspected or known case, I don’t expect there would be a loss in status,” comments Logan, adding, “When Idaho had a case last year, they didn’t lose their status.” Brucellosis was recently discovered in domestic bison on Ted Turner’s Flying D Ranch near Bozeman, Mont. Montana State Veterinarian Marty Zaluski says the discovery is not likely to impact Montana’s brucellosis-free status.
For more information contact Wyoming State Veterinarian Jim Logan at 307-857-4140 or Wyoming Assistant State Veterinarian Bob Meyer at 307-777-6440. Echo Renner is a field editor for the Wyoming Livestock Roundup and can be reached at firstname.lastname@example.org.