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

Orf virus (ORFV) is the etiological agent of Contagious Ecthyma, a global 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 first report from the Iberian Peninsula and from South America. The assembled genomes of the ARA, CHB, HRE, and NAV strains of ORFV were found to be 137 891 , 137 160, 137 340, and 137 214 bp long, respectively, each contained 132 genes, and all showed high amino-acid identity and similar lengths compared to the reference strain NZ2. We performed a microsatellite analysis to identify molecular signatures associated with host species (sheep or goat). In addition, the analysis of 32 selected genes showed that the median nucleotide substitution rate for the worldwide cluster 3 that includes the four samples described in this study, was 2.6 x10-5 subs/site/year (9.2x10-8-6.7x10-5-95% HPD) placing the TMRCA (median divergence time) around 1730. Genetic characterization of ORFV strains not only allows epidemiological studies but also represents the first step towards developing molecular tools for diagnostics and vaccines.