DESENVOLVIMENTO DE UM ELISA PARA A DETECÇÃO DE ANTICORPOS SÉRICOS CONTRA O VÍRUS DA LEUCOSE BOVINA.

The Enzootic bovine leucosis is a chronic disease that causes economic losses to cattle. The detection of infected animals is an important step to control the disease. Therefore, this study aimed to investigate the prevalence of the virus in the Alto Uruguai Catarinense (Brazil) region and in parallel develop an enzyme linked immunosorbent assay (ELISA) able to discriminate serologically positive and negative animals for bovine leukemia virus (BLV). For ELISA standardization, antigen and serum controls block titrations were performed. Then, 289 bovine serum samples collected from 42 dairy herds were analyzed. The results obtained were compared with Agar Gel Immunodiffusion (AGID). The comparative analysis concluded that the developed ELISA showed a satisfactory performance and was able to discriminate between infected and uninfected animals. Although the sensitivity (80.2%) and specificity (71.2%) of the test showed lower values than those found in previous studies using commercial kits or in-house assays, the ELISA developed can be associated with IDGA as a screening test, in order to reduce the number of false negatives. The prevalence of antibodies against BLV found was 31% for AGID and 45% for ELISA. From 42 properties, 47.6% had at least one positive animal in the ELISA. These results indicate that bovine leukosis is widespread in dairy herds of the region analyzed. Therefore, the test developed could be used as an initial screening tool, thus contributing to the serological monitoring of the herd [ABSTRACT FROM AUTHOR]