A Deeper Insight into Evolutionary Patterns and Phylogenetic History of ORF Virus through the Whole Genome Sequencing of the First Italian Strains

Abstract

Orf virus (ORFV) is distributed worldwide and is the causative agent of contagious ecthyma that mainly occurs in sheep and goats. This disease was reported for the first time at the end of 18th century in Europe but very little is currently known about the temporal and geographic origins of this virus. In the present study, the use of new Italian whole genomes allowed for better inference on the evolutionary history of ORFV. In accordance with previous studies, two genome types (S and G) were described for infection of sheep and goats, respectively. These two well-differentiated groups of genomes originated for evolutive convergence in the late 1800s in two different areas of the world (Europe for S type and Asia for G type), but it was only in the early 1900s that the effective size of ORFV increased among hosts and the virus spread across the whole European continent. The Italian strains which were sequenced in the present study were isolated on the Mediterranean island of Sardinian and showed to be exclusive to this geographic area. One of them is likely representative of the early European forms of ORFV which infected sheep and became extinct about one century ago. Such an ancient Sardinian strain may have reached the island simple by chance, where it quickly adapted to the new habitat.

Genetic characterization and Temporal dynamics of Orf virus in Small Ruminants from Republic of Niger and parts of Northern Nigeria sold in Livestock Market in Abuja

“…In addition the calculated evolutionary rate of the African Orf virus B2L genes was 7.45 x 10 -4 , 95% HPD (3.46 x 10 -4 to 1.17 x 10 -3 ) substitutions/ site/year. This is higher than the calculated evolutionary mean rate of 1.32 x 10 -6 derived for whole Orf gene sequences from a recent study 23 . This observation might be due to the small genome size analyzed, as well as the limited number of sequences, but reelects the relatively slower evolutionary rate for DNA viruses in comparism to RNA viruses.…”

Orf virus DNA prime-protein boost strategy is superior to adenovirus-based vaccination in mice and sheep

“…Recently, researchers have been working on the development of a safe and effective vaccine for Orf, and there have been some progresses, such as the attenuated vaccine ( 4 ) and the DNA vaccine related to the important immunogenic genes of ORFV ( 15 ), which have demonstrated effective in eliciting specific antibodies against ORFV. However, attenuated vaccines usually have a risk of virulence reversion ( 16 ).…”

“…ORFV is a double-stranded DNA virus, which belongs to the Poxviridae family, parapoxvirus genus. The genome of ORFV contains around 134 genes, and the central core region (ORFs 009-111) is highly conserved and plays critical roles in maintaining viral replication, maturation and morphogenesis ( 15 ). B2L and F1L genes are highly conserved, PCR is often used to detect the existence of these two genes in clinic to prove the infection of ORFV ( 16 , 17 ).…”

Pockenvirusinfektionen in der Dermatologie

“…Orf beim Menschen wird überwiegend durch Typ S verursacht; dementsprechend sind Schafe als bedeutendste Infektionsquelle für humane Orf zu betrachten. 221 Eine der ersten Beschreibungen von Orf beim Menschen stammt aus dem Jahr 1934. 222 Seitdem wird häufig und weltweit über zoonotische Übertragungen berichtet, die durch Kontakt mit infizierten Tieren zu Erkrankungen beim Menschen führen.…”