Examination of lumpy skin disease virus (LSDV) isolates from different geographic origins and times revealed that the assays developed in our laboratory for differentiating between virulent viruses and Neethling vaccine virus (NVV), using exclusively Israeli viruses, are of general nature that is useful in most if not all endemic areas in which the NVV is serving for vaccination. Recently it was revealed that LSDV 126 gene of the field viruses contains a fragment consisting of, 27 bp or 9aa, duplicate, while in the vaccine viruses have only one copy. Phylogenetic analysis of a 532-bp segment carrying the LSDV126 gene, and whole virus genome sequences, revealed that LSD viruses fall into two groups: virulent and vaccine viruses. Moreover, it seems that all capripox viruses that have partial or no ability to infect cattle carry only one copy of the 27-bp fragment, suggesting that LSDV126 gene has a vital role in the capacity of capripox viruses to infect cattle. In silico analysis of potential antigenic of the LSDV126 gene regions revealed that an LSDV126 gene with only one copy of the repeat lacks a potentially important antigenic epitope, supporting its possible significance in cattle infection. This study widens the scope of the nature and possible role of the LSDV126 gene in the life cycle of LSDV.

Keywords: Lumpy kin Disease Virus, LSDV, LSDV126 gene, Phylogenic