Molecular Characterization of Publicly Available NDV F Gene Sequences From Bangladesh (2010-2024).

Newcastle disease, caused by avian orthoavulavirus serotype 1, is a highly contagious and economically devastating viral infection affecting both wild and domestic birds. The disease is characterized by severe respiratory, gastrointestinal, and neurological symptoms, often leading to high mortality and substantial production losses, particularly in commercial poultry. In Bangladesh, multiple virulent and avirulent Newcastle disease virus (NDV) genotypes and subgenotypes continue to circulate despite ongoing vaccination programs. This research presents a comprehensive analysis of the genetic landscape of prevalent NDV strains in Bangladesh between 2010 and 2024 using full-length coding sequences of the fusion (F) gene. Specifically, we focused on genotypes, subgenotypes, host species, and annual distribution patterns in the country. We further investigated phylogenetic relationships, evolutionary divergence, and amino acid substitutions in the full-length F protein. Comparative analyses of amino acid variability and sequence similarity between currently used vaccine strains and prevalent Bangladeshi field isolates were also scrutinized. We have unraveled considerable genetic divergence, and highlighted mismatches in genotypic coverage. These findings underscore the urgent need to reevaluate existing NDV vaccines strain to ensure improved protection against circulating NDVs in Bangladesh.