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, 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 fromArgentina (HRE and CHB), representing the first report from the Iberian Peninsula and from South America. The assembled genomesof 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, eachcontained 132 genes, and all showed high amino-acid identity and similar lengths compared to the reference strain NZ2. We performeda microsatellite analysis to identify molecular signatures associated with host species (sheep or goat). In addition, the analysis of 32selected genes showed that the median nucleotide substitution rate for the worldwide cluster 3 that includes the four samples describedin 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 f irst step towards developingmolecular tools for diagnostics and vaccines.