Brucellosis Affected Cattle Herd Confirmed in Wyoming’s Park County

by Colter Brown

A cattle herd in Park County was confirmed as “Brucellosis affected” following laboratory testing at the Wyoming State Veterinary Laboratory (WSVL), Laramie. Laboratory results were confirmed at the National Veterinary Services Laboratory (NVSL), in Ames, Iowa, December 6, 2022. One cow tested positive on blood tests at both laboratories. Further testing, including bacterial culture, will be conducted in addition to the serology tests already completed.

Brucellosis positive cattle are not uncommon within Wyoming’s Designated Surveillance Area (DSA), encompassing all or part of six counties along the western side of the state. Specified cattle from the DSA are required to be tested within 30 days prior to change of ownership or movement from counties within the DSA. The affected herd was quarantined following confirmation of test results, and will remain under quarantine until three consecutive, negative, whole-herd tests have been completed. No contact herd quarantines are expected at this time.

The testing is being conducted as a cooperative effort between herd owners, private veterinary practitioners, Wyoming Livestock Board (WLSB) personnel, and United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), Veterinary Services (VS) personnel. Epidemiologic interviews with herd owners are ongoing and quarantine herd plans will be developed with each herd owner associated with the case where indicated.  Epidemiologic tracing will be conducted in the upcoming weeks by WLSB and APHIS personnel.

“Finding brucellosis in our DSA is not an unexpected event,” said Dr. Hallie Hasel, Wyoming State Veterinarian. “We have a reservoir of brucellosis in wildlife in northwest Wyoming that occasionally will spill over into cattle. Our producers do an excellent job of mitigating risks and trying to prevent brucellosis in their cattle herds. This situation illustrates the value and effectiveness of our surveillance program in Wyoming. We found this case before the disease spread to other areas and are dealing with it appropriately.”

A brucellosis suspect herd was released from quarantine in Sublette County on December 13, 2022. The whole herd test did not reveal any further suspects, and follow-up testing on the suspect cow did not confirm the disease.

Dr. Hasel would like to thank the producers and veterinarians in both Park and Sublette Counties for their cooperation in very difficult situations. “Herd surveillance testing in Sublette County was completed expediently due to the producer’s cooperation and management efforts, along with local veterinarians’ willingness to add more to an already packed schedule.”


WY Livestock Board

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