Evaluation of the fluorescence polarization assay and comparison to other serological assays for detection of brucellosis in cervids

The complement fixation test (CFT), competitive enzyme immunoassay (CELISA) , indirect enzyme immunoassay (IELISA) and fluorescence polarization assay (FPA) were evaluated for the detection of antibodies to Brucella abortus an d Brucella suis biotype 4 in caribou (Rangifer tarandus caribou), elk (Cerv us elapus), red deer (Cervus elapus), and reindeer (Rangifer tarandus taran dus). When combining the data the FPA and the CELISA were determined to be the most suitable tests for serodiagnosis of Cervidae. The overall actual s ensitivity of the CFT and the IELISA was 100%. The overall actual sensitivi ty for the CELISA and FPA was 99%. The overall relative specificity of the CFT (including treatment of anti-complementary data as positive or negative for analysis), the CELISA, the IELISA and the FPA were 65%, 93%, 99%, 99%, and 99%, respectively. The specificities of the buffered plate agglutinati on test (BPAT), the CFT, the CELISA, the FPA and the IELISA for 55 elk vacc inated with B. abortus strain 19 and tested 4 mo post vaccination were 14%, 31%, 51%, 84%, and 2%, respectively. The FPA is the diagnostic test of cho ice because it has sensitivity and specificity values comparable to the CEL ISA; it has the capability to distinguish vaccinal antibody and antibody re sulting from exposure to crossreacting organisms such as Yersinia enterocol itica 0:9 from antibody to Brucella spp, in most cases; it is technically s imple to do; it is adaptable to field use and it is relatively inexpensive.