The whole genome analysis of four Orf virus strains from Europe and South America.

Abstract

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma (CE), a worldwide disease that mainly affects sheep, goats, wild ruminants, and humans. Here, we determined the complete genome sequence of two ORFV strains from Spain (NAV and ARA) and two from Argentina (HRE and CHB), representing the second report from Europe and the first from South America. The assembled genomes of the ARA, CHB, HRE, and NAV strains of ORFV were found to be 137,891 bp, 137,160 bp, 137,340 bp, and 137,214 bp long, respectively, containing 132 genes in each strain, showing high amino acid identity and similar lengths to the reference strain NZ2. We performed a microsatellite analysis to determine a molecular signature for strains that differ in their host (sheep or goat). In addition, the analysis of 32 specially selected genes showed that the nucleotide substitution rate for this dataset was 3.2x10-5 subs/site/year (95% HPD 4.2X10-8 -7.6 X10-5) with a median value of 2.8 x 10-5 subs/site/year, placing the TMRCA (median divergence time) in 1661. The genetic characterization of ORFV strains not only allows epidemiological studies but is the first step toward the development of molecular tools oriented to diagnostics and vaccines.