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Diagrammatic sketch of influenza A virus structure. The influenza A virus is composed of eight segments of negative-sense ribonucleic acid (RNA) coupled with nucleoprotein (NP). The internal proteins include polymerase complex, nuclear export protein (NEP), and matrix 1 (M1) protein. The surface proteins are hemagglutinin (HA), neuraminidase (NA), and matrix 2 (M2) protein.
