TITLE:
Determining a Diagnostic Cut-Off on Fluorescence Polarization Assay (FPA) for Bovine Brucellosis in Carchi, Ecuador
AUTHORS:
Ibarra Marcelo, Benavides Hernán, Salgado Ruth, Gutiérrez Milena, García Judith, Peña Julio, Herrera David, Mina Jorge, Campos Martín, Puga Byron
KEYWORDS:
Brucella, Diagnosis, Fluorescence Polarization, Sensitivity, Specificity
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.7 No.4,
October
10,
2017
ABSTRACT: Serology is the foundation
of any brucellosis control and eradication program worldwide, thus it is
important to define accuracy diagnostics assays and cut-off of those assays, due to variations from country
to country and even among specific areas in the country. The variation of
cutoff values depended on: prevalence of disease, vaccination status, animal
management, and control and eradication programs. Therefore, a cut-off for the diagnosis of bovine
brucellosis through fluorescence polarization assay (FPA) in Carchi—Ecuador was
determined. The survey has been carried out in Carchi province of Ecuador, who
is considered a province of high prevalence of brucellosis and the vaccination
status is unknown due to the lack of
registers. Sera samples (n = 200)
were obtained from individual cows from randomly selected herds. Blood sera
were tested through Fluoresce Polarization Assay (FPA) and competitive
enzyme-linked inmunosorbent assay (cELISA) as confirmatory test, and then receiver operating characteristic (ROC)
analysis was done. The sensitivity and specificity values of FPA were 88.7% and 92.50% respectively using a cut-off of 89.90 mP. Moreover, the area under the curve showed
that 92.2% is the probability accuracy of the test. The advantage of the FPA is that it is a test with good characteristics
of sensitivity and specificity as well as a simple and
quick test.