Heterogeneity determination of bovine leukemia virus genome in Santa Catarina state, Brazil

Abstract

Bovine leukemia virus (BLV) is a member of Retroviridae family, genus Deltaretrovirus, and the main viral agent responsible for economic loses in dairy herds. Some studies have been carried out about BLV genotypes, and at least seven genotypes were found out in samples of different regions of the world. The objective of this study was to identify BLV samples from seropositive dairy cattle in Santa Catarina state, Brazil, using molecular techniques. Blood samples were collected (454) from dairy cattle from 31 different farms, and serology using agar gel immunodiffusion test (AGID) was performed. After that, 191 seropositive samples were submitted to DNA extraction, and in 77 samples the polymerase chain reaction (PCR) for amplification of a 440 bp fragment of the env gene was performed. Nineteen DNA samples were subjected to restriction fragment length polymorphism (RFLP) analysis by digestion of the PCR fragment by five restriction endonucleases - BamHI, HaeIII, Tru9I, TaqI, and MwoI. It was found 42% seropositive animals (191/454) and 68% positives of the farms (21/31). The PCR showed 80.5% (62/77) of animals positive. The RFLP analysis identified five different genotypes dispersed by Santa Catarina state, with the highest prevalence for genotype X (47.4%). Overall, our results identified the viral genotypes present in dairy cattle and the prevalence of new variants in representative farms from Santa Catarina state.

Diagnosis and phylogenetic analysis of bovine leukemia virus in dairy cattle in northeastern Brazil

“…On the other hand, surveys using molecular diagnostic techniques targeting the identification of viral DNA are even more limited. In southeastern and southern Brazil, respectively, D'Angelino et al ( 26) reported 4.8% of CNS tissues from BLVpositive cattle in the state of São Paulo, and Rodakiewicz et al (37), found a high rate of 80.5% (62/77) of positive animals in the State of Santa Catarina. Although serological studies are observed in the northeastern region, direct detection of virus DNA by molecular techniques has not been observed.…”

Intercurrence between bovine leukosis virus infection and mastitis in dairy cattle

“…In South America, genotypes I, II, IV, V, VII, and IX have already been identified, and in Brazil genotypes I, II, V, VI, and VII (Polat, Takeshima, & Aida, 2017;Gregory et al, 2017). In a study performed in Santa Catarina State/Brazil, it was observed the circulation of genotypes I, II, VIII, IX, and the genotype X as the most prevalent (47%) (Rodakiewicz et al, 2018). Yu et al (2019) identified a new genotype (G11) in genotypic studies of BLV types circulating in Heilongjiang, northeast China.…”