Influenza A
Explain how mutation and reassortment can result in the emergence of Influenza A viruses. Describe and discuss the role of the Haemagglutinin in host adaptation, providing examples of host and virus determinants that are important in influenza host-switching. Essay Plan: Influenza A: The virus itneslt is a negative sense ssRNA with 8 segments: PB1, PB2, PA, HA, NP, HA, M, NS, translating to more than 14 proteins. With a viral coat having 2 major glycoprotiens the haemagglutinin (HA) - mediates cell entry through binding to sialic acid and is a host-range determinant, and is also the main target of neutralising antibodies neuraminidase (NA), there are currently known to be 18HA subtypes and 11NA subtypes. Context of Influenza - Influenza A: It was the cause of the great Spanish Flu pandemic of 1918 causing the death of around 50 million individuals. The virus and its subtype H1N1 was established using reverse genetics using viral particles found from preserved samples from ...