Babatunde Motayo

and 6 more

Background: Orf virus (ORFV) is an important zoonotic parapox virus, with 100% morbidity. It affects mainly domesticated ruminants such as sheep and goats. This study determined the molecular epidemiology of ORFV local as well as imported sheep and goats in Nigeria and evolution of ORFV in Africa. Methods: A total of 30 small ruminants with orf were sampled in a livestock market Abuja Nigeria.Skin scabs from pathological tissues were collected and processed for viral genomic DNA. PCR and Sanger sequencing of B2L gene of ORFV. Phylogenetic analysis, phylogeography, and Bayesian skygird reconstruction (BSK), including mutational changes were performed on B2L gene sequences. Results: An ORFV positivity rate of 67% was determined from samples. Animals <2 years had the highest prevalence of 76.5%.Hundred percent attack rate was observed among the Uda and WAD breeds, followed by Niger 71.4%, Kano Brown 66.7%, Yankasa 25% and Balami 0% breeds. ORFV from Africa breeds clustered into 2 major lineages, Asian and African, with an evolutionary rate of 7.45 × 10 -4, 95% HPD (3.46 × 10 -4 to 1.17 × 10 -3) substitutions/ site/year. Viral population demography showed a constant population growth with a slight rise in viral population growth towards year 2020. Conclusion: We report molecular evolution of ORFV in Africa and identified gap in molecular data; we recommend regional molecular surveillance of ORFV and other zoonotic trans-boundary diseases in global health prevention and control effort.