Influenza Viruses: Molecular Virology

Abstract Influenza viruses cause mild to potentially lethal respiratory disease. Influenza A viruses cause annual outbreaks of local scale and occasional outbreaks of global scale, as witnessed with the pandemic of 2009 that was caused by an influenza A viruses of the H1N1 subtype. Influenza B viruses also cause disease in humans, whereas influenza C viruses are not a recognised public health concern. Influenza A, B and C viruses share many similarities in their coding strategies and life cycles, but can also be distinguished by key differences. Here we summarise the molecular virology of influenza A, B and C viruses, that is the similarities and differences in coding strategies, the replication cycle and the functions of the viral proteins. Key Concepts: Influenza A, B and C viruses differ in their impact on human health. Although influenza A, B and C viruses share many similarities, they differ in their coding strategies. The basic functions of the viral proteins are now understood, but many questions remain about the interplay between the viral proteins, and the interplay between viral and cellular proteins.