Abstract

As the prevalence of wildlife and cattle brucellosis in the United States continues to fall, the effects of false-positive serology become increasing detrimental to both wildlife and agricultural managers. Cross reactions between commensal bacteria that share surface proteins with Brucella on standard serology have continued to frustrate the efforts of regulatory agencies to control Brucella and increase the need for more reliable methods of diagnosing infection. Because of these difficulties, the western immunoblot was evaluated for use in diagnosing Brucella abortus infections in elk. One hundred thirty-three samples encompassing four different elk herds were tested using management-standard buffered antigen and CARD serology, as well as western immunoblots. Samples were analyzed from Wyoming animals experimentally challenged with Brucella abortus strain 2308 and animals naturally infected with B. abortus biovar 1 as positive controls. For negative controls, sera from two different California elk herds were used. Negative serologic tests, negative cultures, and no history of herd infection or disease support non-infected status. By comparing sensitivities and specificities among the tests used, the western immunoblot indicates higher reliability than standard serology in establishing disease status in elk.