Influenza is a very serious pathogen, causing widespread mortality across the world. The young, the elderly and those who have a comprised immune system are most at risk. Seasonal strains are common and can kill over 50,000 people a year1. Influenza can also produce pandemic strains which spread very quickly and can originate from animals such as birds or swine. An example of this is the 1918 influenza pandemic, strain H1N1 which was identified to have originated in birds and killed between 40-50 million people2.
The influenza A virus (IAV) is a member of the orthomyxoviridae family and has a negative sense, single stranded RNA genome split into 8 segments, containing 11 genes. The virus possesses a lipid envelope which is produced from the host cell. Spikes protrude from this membrane which consist of hemagglutinin (HA), which facilitates receptor binding and fusion, and neuraminidase (NA) which cleaves sialic acids on the outside of the cell allowing release of virions3. Also on the envelope is the M2 protein which acts as an ion channel, important in viral assembly and budding. Inside, the virus is made up of the ribonucleoprotein (RNP) complex which is comprised of …show more content…
They do this via antigenic variation5. Influenza A viruses can undergo antigenic shift, which is the change of the HA and NA subtypes on the viral surface. There are 15 known subtypes of HA and 9 known subtypes of NA5. For example, the H3N2 subtype caused an epidemic in 2003-20045 compared to the H1N1 strain causing a pandemic in 19182. Different subtypes are more pathogenic than others, however the introduction of a new HA subtype into human infection is likely to induce a new pandemic5.
Influenza viruses can also undergo antigenic drift. This is where mutations occur on the antibody-binding sites on HA, NA or both5. This means the viruses can’t be targeted by
The influenza A virus (IAV) is a member of the orthomyxoviridae family and has a negative sense, single stranded RNA genome split into 8 segments, containing 11 genes. The virus possesses a lipid envelope which is produced from the host cell. Spikes protrude from this membrane which consist of hemagglutinin (HA), which facilitates receptor binding and fusion, and neuraminidase (NA) which cleaves sialic acids on the outside of the cell allowing release of virions3. Also on the envelope is the M2 protein which acts as an ion channel, important in viral assembly and budding. Inside, the virus is made up of the ribonucleoprotein (RNP) complex which is comprised of …show more content…
They do this via antigenic variation5. Influenza A viruses can undergo antigenic shift, which is the change of the HA and NA subtypes on the viral surface. There are 15 known subtypes of HA and 9 known subtypes of NA5. For example, the H3N2 subtype caused an epidemic in 2003-20045 compared to the H1N1 strain causing a pandemic in 19182. Different subtypes are more pathogenic than others, however the introduction of a new HA subtype into human infection is likely to induce a new pandemic5.
Influenza viruses can also undergo antigenic drift. This is where mutations occur on the antibody-binding sites on HA, NA or both5. This means the viruses can’t be targeted by