Probe capture enrichment next-generation sequencing of complete foot-and-mouth disease virus genomes in clinical samples.

Next-generation sequencing (NGS) techniques offer an unprecedented "step-change" increase in the quantity and quality of sequence data rapidly generated from a sample and can be applied to obtain ultra-deep coverage of viral genomes. This is not possible with the routinely used Sanger sequencing method that gives the consensus reads, or by cloning approaches. In this study, a targeted-enrichment methodology for the simultaneous acquisition of complete foot-and-mouth disease virus (FMDV) genomes directly from clinical samples is presented. Biotinylated oligonucleotide probes (120 nt) were used to capture and enrich viral RNA following library preparation. To create a virus capture panel targeting serotype O and A simultaneously, 18 baits targeting the highly conserved regions of the 8.3 kb FMDV genome were synthesised, with 14 common to both serotypes, 2 specific to serotype O and 2 specific to serotype A. These baits were used to capture and enrich FMDV RNA (as cDNA) from samples collected during one pathogenesis and two vaccine efficacy trials, where pigs were infected with serotype O or A viruses. After enrichment, FMDV-specific sequencing reads increased by almost 3000-fold. The sequence data were used in variant call analysis to identify single nucleotide polymorphisms (SNPs). This methodology was robust in its ability to capture diverse sequences, was shown to be highly sensitive, and can be easily scaled for large-scale epidemiological studies.