Abstract
The article presents the results of a comprehensive molecular diagnostic study aimed at detecting infection with the brucellosis pathogen Brucella abortus in cattle from Aisary village, Kostanay District, Kostanay Region. At the first stage, all 94 blood samples were tested using the complement fixation test (CFT), which yielded 10 positive results. To clarify the diagnosis, the same samples were further examined by the agglutination reaction (AR) method, which revealed 3 positive and 7 inconclusive results. To obtain more reliable data and confirm the presence of the pathogen, PCR analysis was performed using specific primers for Brucella abortus DNA. As a result of the molecular study, the presence of pathogenic DNA was confirmed in only 2 out of 10 samples; both had previously tested positive in the AR. The remaining 8 samples, including 7 inconclusive and one suspected false-positive AR result, showed no evidence of Brucella abortus DNA. Thus, PCR confirmed infection in only two animals and excluded the disease in the rest, highlighting the high accuracy and diagnostic value of molecular genetic methods when combined with conventional serological approaches for brucellosis detection.