Study of diagnostic value of the reaction of indirect hemaglutination in comparison with enzyme immune assay and other serological tests at cattle brucellosis

Abstract

The results of comparative brucellosis diagnostic studies of blood sera from cattle at farms with different epizootic situations, performed in 2021 in the laboratory of the Caspian Zonal Research Veterinary Institute – a branch of the Dagestan Agriculture Science Centre, are presented in the paper. The diagnostic efficiency of the indirect hemagglutination test (IHA) was studied in comparison with enzyme immunoassay (ELISA), agglutination test (RA), complement fixation test (CFR), rose-bengal test (RBP) and immunodiffusion reaction with O-PS antigen (RID with O-PS antigen). The specificity of these serological tests was confirmed by the negative results of studies of 40 samples of blood serum of non-vaccinated against brucellosis animals at a brucellosis-safe farm. The sensitivity of the tested diagnostic tools was determined using 46 blood serum samples from cows immunized with the B. abortus 82 vaccine at a brucellosis-prone farm. According to the results obtained, in particular, according to a significant percentage of animals positively reacting to brucellosis in RID with O-PS antigen and high titers of RNHA, RA and RSK, it can be stated that the infection in the herd proceeds in an acute form. Thus, positive results were obtained in RNGA in the study of 18 (39.1%), ELISA (LLC NPF “Sibbiotest”) – 29 (63 %), in RSK – 18 (39.1 %), in RA – 15 (32.6 %), RBP – 15 (32.6 %) and RID with O-PS antigen – 7 (15.2 %) blood serum samples. The conducted studies have shown that RNHA is one of the most sensitive tests, which makes it possible to detect a high percentage of animals with brucellosis at a brucellosis-prone farm (39.1% of those studied) in the early stages after infection and surpasses the results of most other serological methods. The results of comparative serological studies of blood serum samples of cattle in RNHA, IEA, RSK, RA, RBP and RID with O-PS confirmed the specificity of the tests and the high sensitivity of RNHA with brucellosis erythrocyte antigen.