Evaluation of the Fluorescence Polarization Assay and Comparison to Other Serological Assays for Detection of Brucellosis in Cervids

Abstract

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 and Brucella suis biotype 4 in caribou (Rangifer tarandus caribou), elk (Cervus elapus), red deer (Cervus elapus), and reindeer (Rangifer tarandus tarandus). When combining the data the FPA and the CELISA were determined to be the most suitable tests for serodiagnosis of Cervidae. The overall actual sensitivity of the CFT and the IELISA was 100%. The overall actual sensitivity 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 agglutination test (BPAT), the CFT, the CELISA, the FPA and the IELISA for 55 elk vaccinated 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 choice because it has sensitivity and specificity values comparable to the CELISA; it has the capability to distinguish vaccinal antibody and antibody resulting from exposure to crossreacting organisms such as Yersinia enterocolitica 0:9 from antibody to Brucella spp. in most cases; it is technically simple to do; it is adaptable to field use and it is relatively inexpensive.

A Comparison of Four Serologic Assays in Screening for Brucella Exposure in Hawaiian Monk Seals

“…The C-ELISA, I-ELISA, and FPA perform well with regards to sensitivity and specificity in sera from wild species whereas the BPAT performed relatively poorly (Gall et al, 2001). Therefore, it is assumed that the BPAT test overestimated the number of positive HMSs in this survey.…”

“…As with other wild species, the FPA test is the diagnostic test of choice for detection of exposure to Brucella in HMSs (Gall et al, 2001). It has the ability, in some cas-es, to distinguish antibody from cross-reacting organisms (e.g., Y. enterocolitica 0:9) from antibody against Brucella spp.…”

“…It has the ability, in some cas-es, to distinguish antibody from cross-reacting organisms (e.g., Y. enterocolitica 0:9) from antibody against Brucella spp. and is marginally better at it than the C-ELISA test; it is technically simple to do; it is adaptable to field use even with hemolysed sera, milk and whole blood; and is relatively inexpensive (Gall et al, 2001). The results we obtained were based on cutoff values established for cattle, but they are probably sufficient for preliminary screening for evidence of Brucella exposure in HMSs.…”

The Use of Fluorescence Polarization Assays for the Detection of Infectious Diseases

“…We have recently described the use of FP assays, using a fluorescein-labeled OPS from Brucella abortus, for the detection of antibodies to Brucella spp. (a gram negative bacterium) in bovids, bison, cervids and swine [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. We have shown that this approach, in principle, can be applied to all gram negative bacteria, which possess OPSs, by extending it to the detection of antibodies to Salmonella spp.…”

“…The assay was evaluated against a variety of commonly used assays (the buffered plate antigen test, the rose bengal plate test, the complement fixation test, the rivanol agglutination test, competitive ELISA, indirect ELISA and culture) in bovine sera [6,[10][11][12][19][20], porcine sera [13][14], bison sera [15], cervid sera [16], bovine whole blood [8,17,19], and bovine milk [8,18,19,21]. In all these studies the FPA was equal, and many times superior to the commonly used assays in terms of sensitivity and specificity, often achieving 99+% for both.…”