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.

Brucellosis is an infectious disease of worldwide distribution, which has a great economic impact due to the productive and reproductive losses that it causes, in addition to the serious public health problem. The aim of this study is to estimate the economic losses, through financial analysis, caused by bovine brucellosis in the province of Carchi, over a one-year period. A random sampling was used to determine the prevalence in the study area, where 2976 animals were considered, and the Rose Bengal (RB) test was used as a screening test and the Fluorescence Polarized Assay (FPA) as a confirmatory test, obtaining a prevalence of 8.2% (244/2976). In addition, parameters associated to the losses caused by brucellosis in cattle were determined by literature review. To estimate costs, field information was collected through a survey of a total of 100 randomly selected farmers. The loss estimated due to calves lost as a result of abortions and neonatal death was USD. 79170.00. The loss due to death of 4 cows as a result of metritis was estimated at USD. 5000.00. The cost of examination and treatment of aborted cows was USD. 20100.00. The losses due to reduction in milk production from aborted and non-aborted seropositive cows were estimated at USD. 158114.