Dynamic evolution of peste des petits ruminants virus in sheep and goat hosts across India reveals the swift surge of F gene.

Peste des petits ruminants (PPR), an acute febrile viral disease impacting goats and sheep flocks, manifests with pyrexia, mucopurulent nasal and ocular discharges, necrotizing and erosive stomatitis, pneumonia, and enteritis. The disease-instigating agent, PPR virus, pertains to the Morbillivirus caprinae genus in the Paramyxoviridae family. The endemic presence of PPR in India results in notable economic losses due to heightened mortality and morbidity in infected animals. Understanding viral pathogen evolution is pivotal for delineating their emergence in diverse environments. This study explores the molecular evolutionary patterns of PPRV, concentrating on the N and F structural genes isolated from Indian sheep and goats. Analyzing evolutionary rate, phylogenetics, selection pressure, and codon usage bias, we determined the time to the most recent common ancestor (tMRCA) as 1984, 1973, 2000, and 2004 for goat and sheep's N and F genes, respectively, with evolutionary rates ranging from 2.859 x 10³ to 4.995 x 10⁴. The F-gene is found to exhibit a faster evolution than the N-gene, indicating apparent virus transmission across the regions of India, as supported by phylogenetic analysis. Codon usage bias examination, incorporating nucleotide composition and various plots (effective number of codon plot, parity plot, neutrality plot), suggests the evolution in India influenced by both natural selection and mutational pressure, resulting in alterations in the virus's codon bias. The integrated analysis underscores the significant role of selection pressures, implying PPRV's co-evolution and adaptations influenced by various genes. Insights from this study can guide effective disease control and vaccine development, aiding in managing PPR outbreaks in India and beyond.