Fluorescent polarization assay, two versions of indirect and competitive enzyme- linked immunoassay for brucellosis diagnosis in vaccinated buffaloes (Bubalus bubalis)

ABSTRACT: The fluorescence polarization assay (FPA), two variants (V) of the indirect enzyme-linked immunosorbent (I-ELISA) and competitive (C-ELISA) were evaluated in buffaloes to detect antibodies against Brucella spp. V1 I-ELISA identifies them through monoclonal (M23) anti-bovine IgG (I-ELISAM23) V2 ProteinA / G (I-ELISA-A/G). Serum samples 862 (Bubalus bubalis) from Northeast Argentina (NEA) analyzed using complement fixation test (CFT) as reference. Receiving Operator Characteristic (ROC) analysis defined for area under curve (AUC) determined cutoff points, sensitivity (Se) specificity (Sp) each test. CFT identified 107 positive 755 negative sera. best AUC (0.986), Concordance with (96.3%) kappa value (0.843) was obtained by A/G This showed highest Se (95.33%) C-ELISA Sp (97%). FPA failed measure 23 (2.65%) serum due unsuccessful reading. M23 proved be ineffective diagnose brucellosis bubaline four serological tests points lower than those standardized bovines. As conclusion, A/G, its limitations would effective techniques diagnosis NEA, requiring an appropriate cut-off point guarantee their maximum performance this species.