Evaluation of diagnostic tests to bovine leukemia virus Avaliação de testes de diagnóstico para o vírus da leucemia bovina

169 Summary: Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). After infection with BLV there is no detectable viremia but there is a strong and persistent humoral immune response to structural proteins, essentially the gp51 envelope glycoprotein and the major core protein p24. Polymerase chain reaction (PCR) with primers used to amplify part of env gene, agar gel immunodiffusion (AGID) which employs a crude antigen preparation derived from concentrated cell culture fluid, two commercial immuno enzymatic assays (ELISAs) and one ELISA with recombinant gp51 antigen were used to detect proviral DNA and BLV antibodies in DNA and serum from bovines of Goias (GO), Mato Grosso do Sul (MS), Minas Gerais (MG) and Paraná (PR) States of Brazil. The evaluated tests presented good results. The ELISA tests were more sensitive than AGID, and highly specific. PCR sensitivity should be improved, nevertheless it is a good complementary tool for serologic diagnosis.