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
Abstract
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.