Tracing viral transmission and evolution of bovine leukaemia virus through long-read Oxford Nanopore sequencing of the proviral genome
- shared.published_on: May 28 2022
Bovine leukaemia virus (BLV) causes Enzootic Bovine Leukosis (EBL), a persistent life-long disease resulting in immune dysfunction and shortened lifespan in infected cattle. The shortened lifespan and decreased milk production of infected animals severely impacts the profitability of the US dairy industry. Our group has found that 94% of dairy farms in the USA are infected with BLV with an average in-herd prevalence of 46%. This is partly due to the lack of clinical presentation during the early stages of primary infection and the elusive nature of BLV transmission. This study sought to validate a near-complete genomic sequencing approach for reliability and accuracy before determining its efficacy in characterising the sequence identity of BLV proviral genomes for the purposes of viral contact tracing. These BLV-infected animals were comprised of seven adult dam(mother)/daughter pairs, from one commercial dairy herd, that tested positive by ELISA and qPCR. The results demonstrate sequence identity or divergence of the BLV genome from the same samples tested in two independent laboratories, suggesting both vertical and horizontal transmission in this dairy herd. This study supports the use of Oxford Nanopore Technologies (ONT) sequencing for the identification of viral SNPs that can be used for retrospective genetic contact tracing of BLV transmission.
