Enhanced Diversifying Selection on Polymerase Genes in H5N1 Clade 2.3.4.4b: A Key Driver of Altered Species Tropism and Host Range Expansion.

A recent study investigated the genetic factors behind the expanded host range and pathogenicity of highly pathogenic avian influenza H5N1 clade 2.3.4.4b viruses. The researchers found that the polymerase genes PB2, PB1, and PA in these viruses undergo significant selection pressures, which play a critical role in viral adaptation, interspecies transmission, and virulence. The study suggests that exogenous factors such as altered bird migration patterns and increased host susceptibility may have contributed to the expanded host range. The researchers emphasize the importance of comprehensive surveillance to monitor transmission among avian and mammalian hosts in order to mitigate the risk of emergent novel variants with increased pathogenicity. [Extracted from the article]