Molecular perspective of Orf virus infection in Türkiye: a retrospective study between 2003 and 2021.

Viral agents in the Parapoxvirus genus of the Poxviridae family that infect ruminants also have zoonotic importance. Orf virus (ORFV), a member of this genus, causes infections primarily in sheep and goats, recently as well as in cattle and other ruminant species. Additionally, they pose a zoonotic risk to individuals who work with animals, such as farmers, animal handlers, and veterinarians. In the present study, the molecular characterization of the four ORFV genes responsible for immune response (ORFV011/B2L and ORFV059/F1L), inhibition of cellular interferon activity (ORFV020/VIR), virulence and immune evasion (ORFV127/vIL-10) of Ruminant Parapoxvirus from Türkiye was performed. In this study, ORFV positive samples obtained from various geographical regions in Türkiye were investigated using a nucleic acid-based PCR technique. For this purpose, PCR was performed using specific primers targeting four gene regions (ORFV011-B2L, ORFV059-F1L, ORFV020-VIR, and ORFV127-vIL-10). All positive samples were subjected to sequence analysis for the respective gene regions. The proximity and distance of ORFV positive samples to other sequences in the GenBank database were determined by using phylogenetic analyses. The analyses revealed that ORFV strains circulating in Türkiye exhibited heterogeneity over the years and showed close genetic relationships with ORFVs from various regions, particularly India, China, and Brazil. It is noteworthy that the viruses circulating in the field in Türkiye in recent years are far from some vaccine strains. When evaluated in terms of vaccine effectiveness, it is recommended that this situation be evaluated in order to create an immune response that will cover field infections.