English: Influenza A replication cycle. The virus recognizes specific receptors expressed on the host cell surface using HA and enters cells via endocytosis. After fusion of the viral envelope and endosomal membrane, vRNPs are released into the cytoplasm and translocate into the nucleus to initiate replication. RdRP is responsible for both viral mRNA transcription and vRNA replication. Newly synthesized vRNPs are exported to the cytoplasm, and assembly of progeny virions occurs near the plasma membrane. NA facilitates budding of new virions from host cells. Anti-influenza drugs inhibit various steps of the influenza virus replication cycle.