Detection of Virulent Genotype VII Newcastle Disease Virus in Lebanese Poultry Using Partial F Gene Sequences Reveals Regional and Global Genetic Relatedness
Newcastle disease virus (NDV) continues to threaten poultry industries worldwide, with genotype VII strains currently dominating outbreaks across the Middle East. In Lebanon, data on circulating NDV lineages remain scarce. This study molecularly characterizes three NDV isolates obtained in Spring 2025 from commercial and backyard poultry farms in Lebanon, where birds exhibited respiratory and/or neurological signs. Virus propagation was conducted in embryonated chicken eggs, and successful replication was confirmed by hemagglutination activity. Reverse transcription PCR targeting a 254 bp fragment of the fusion (F) gene consistently yielded the expected amplicons from all samples. Sequencing revealed the virulent polybasic cleavage site motif ^112RRQKR^117 in all isolates. Phylogenetic analysis placed the Lebanese viruses within genotype VII cluster, showing 100% nucleotide identity with an Indonesian reference strain and close clustering with isolates from neighboring Middle Eastern and North African countries, as well as South and Southeast Asia. Despite different vaccination profiles, all isolates exhibited identical partial F gene sequence. These findings highlight the dominance and persistence of genotype VII NDV in the region, its genetic relatedness to globally circulating strains, and the potential challenges for vaccine efficacy. Continuous molecular surveillance and evaluation of vaccine performance are essential for improving NDV control strategies in Lebanon and the region.
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