Highly Pathogenic Avian Influenza A virus H5N1 (H5N1)

Highly Pathogenic Avian Influenza A virus H5N1 (H5N1) is a virulent subtype of the Influenza A virus that primarily infects avian species but poses a significant zoonotic threat to humans [1, 16]. The virus is defined by its specific surface proteins, Hemagglutinin (H5) and Neuraminidase (N1), which mediate host cell attachment and the release of progeny virions, respectively [8, 23]. In human infections, H5N1 is associated with severe respiratory distress, pneumonia, and a high case-fatality rate, often driven by an intense systemic inflammatory response known as a cytokine storm [12, 18, 21]. While the virus itself is a pathogen rather than a single molecular target, it contains several essential proteins utilized as therapeutic points of intervention, including the M2 ion channel, the RNA-dependent RNA polymerase complex, and the neuraminidase enzyme [1, 5, 10]. Current treatments such as oseltamivir and baloxavir marboxil target these specific viral components to disrupt the replication cycle [2, 9, 12]. However, the therapeutic landscape is challenged by the rapid emergence of drug-resistant strains and the high genetic variability of the virus clades [7, 10, 15].

Other names

Bird fluAvian influenza A (H5N1)HPAI H5N1Influenza A virus subtype H5N1Highly pathogenic avian influenza H5N1

Drugs targeting H5N1 primarily inhibit viral neuraminidase (NA) to prevent the release of progeny virions from host cells, or inhibit the cap-dependent endonuclease within the viral polymerase complex to stop RNA transcription and replication [2, 6, 8, 10]. Other mechanisms include blocking the M2 ion channel to prevent viral uncoating and using sialidase fusion proteins to remove host cell receptors to prevent viral attachment [1, 13, 20].