First complete genome of a fowlpox virus isolated in Bangladesh reveals Asian lineage and clade A1

Fowlpox virus (FPV) is an economically important avian pathogen that continues to cause recurrent outbreaks in poultry worldwide, including Bangladesh, despite routine vaccination. This study aimed to isolate, sequence, and characterize the complete genome of a field FPV strain from Bangladesh. This study aimed to isolate, sequence, and characterize the complete genome of a field FPV strain from Bangladesh to provide insights into its evolutionary characteristics and genomic diversity, thereby improving the understanding of FPV evolution in South Asia. Samples from layer flocks were examined by PCR, and the virus was isolated in embryonated chicken eggs (ECEs). The viral genome was sequenced using next-generation sequencing and compared with global strains. Phylogenetic analyses were conducted using complete genomes and the P4b gene, while mutational, structural, and antigenicity analyses of key viral proteins (serpin, V-type Ig domain, protein tyrosine phosphatase, and ankyrin repeat proteins) were performed using bioinformatics tools. The FPV showed characteristic pock lesions in chorioalantoic membrane of ECEs. The isolate, FPV_MGH-AM01, comprised 288,539 bp with 30.9% GC content and showed 99.69%-99.89% nucleotide identity with global strains, confirming high conservation. Phylogenetic analysis clustered it with South Korean strains, reflecting Asian lineage characteristics, while P4b gene analysis confirmed its placement in clade A1. The genome retained regions deleted in some Chinese and French isolates. A total of 71 mutated genes were identified, including 54 with amino acid substitutions. Structural and physicochemical properties of major proteins were largely conserved, although the V-type Ig domain protein displayed altered antigenicity. In conclusion, this first complete genome of FPV from Bangladesh demonstrates high conservation with various mutations. These findings provide a genomic framework for understanding FPV evolution in South Asia and highlight the need for genomic surveillance to guide vaccine design and control strategies. IMPORTANCE: Fowlpox virus (FPV) remains a persistent threat to the global poultry industry, causing substantial economic losses despite widespread vaccination. This study presents the first complete genome sequence of an FPV isolate from Bangladesh, providing critical insights into the genetic makeup, evolutionary lineage, and protein-level variations of circulating field strains in South Asia. By combining whole-genome sequencing, phylogenetic analysis, mutational profiling, and structural characterization of key immunomodulatory proteins, this work establishes a comprehensive genomic framework for FPV in Bangladesh. The identification of amino acid substitutions in proteins, such as serpin, V-type Ig domain, protein tyrosine phosphatase, and ankyrin repeat proteins, and the assessment of their structural and antigenic implications offer valuable information for understanding viral evolution, host-pathogen interactions, and potential vaccine escape. Overall, these findings enhance our understanding of FPV diversity, facilitate genomic surveillance, and provide a foundation for evidence-based vaccine design and control strategies.