First Isolation and Molecular Characterization of the Bovine Leukemia Virus in the State of Pernambuco, Brazil

Abstract Enzootic Bovine Leukosis (EBL) is an infectious and contagious disease caused by the Bovine Leukemia Virus (BLV), which has a significant economic impact on livestock and a potential zoonotic risk under investigation. In Brazil, although reports of infection exist in several regions, studies on the genetic diversity of the virus are scarce, especially in the Northeast. This study describes, for the first time, the isolation of BLV in the state of Pernambuco, from a blood sample of a seropositive bovine, with laboratory confirmation by Nested-PCR, sequencing of the env gene (gp51), and phylogenetic analysis. The isolation was performed by inoculating leukocytes into MDBK cells, followed by cytopathic effect monitoring and viral DNA validation. Phylogenetic analysis of the env gene (gp51) demonstrated clustering within genotype 1, showing high nucleotide identity with reference isolates previously registered in GenBank. These findings advance our knowledge of BLV genetic diversity in Brazil and highlight the critical need for sustained genomic surveillance, especially considering the potential risk of zoonotic transmission.