Brucellosis Confirmed in Wyoming's Sweetwater County

June 20, 2023

The Wyoming State Veterinarian received confirmation from the National Veterinary Services Laboratory, Ames, Iowa, that seven cattle originating in a herd from Sweetwater County, Wyoming, were positive for brucellosis. The brucellosis positive cattle, also known as reactors, were initially identified at the Wyoming State Veterinary Laboratory (WSVL) in Laramie. The herd was identified on a routine slaughter sample submitted as part of Wyoming’s voluntary custom slaughter brucellosis surveillance program. The sample indicated a possible brucellosis reactor, prompting testing of the herd. 

Although the herd is located in Sweetwater County, there are several links to Wyoming’s Designated Surveillance Area (DSA), where a brucellosis reservoir in elk persists. The Wyoming Livestock Board (WLSB), in collaboration with the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) is conducting an epidemiologic investigation into the source of the herd’s brucellosis exposure. 

A quarantine was placed on the herd following the results from WSVL. The herd will remain under quarantine until required testing has been completed under a brucellosis affected herd plan. The brucellosis reactor cattle will be necropsied at WSVL for further diagnostic testing. “Wyoming’s voluntary custom slaughter brucellosis surveillance program is vital to our state,” said Hallie Hasel, Wyoming State Veterinarian. “We are exceedingly thankful for the custom slaughter facilities submitting samples to WSVL.” 

An epidemiologic investigation is underway, with further testing in the herd of origin and contact herds planned. Preliminary investigation suggests that the brucellosis exposure originally occurred within the Wyoming DSA. The investigation is a cooperative effort between herd owners, WLSB, and USDA APHIS. Epidemiologic tracing will be conducted in the coming weeks by both WLSB and USDA APHIS personnel.

For further information, please contact Dr. Hallie Hasel, 307.840.1389, WLSB office 307.777.7515, or email 

Source: Wyoming Livestock Board