Definition – What is the influenza virus?
The one influenza virus does not actually exist. Rather, the triggers of influenza are a whole group of viruses, the so-called influenza viruses type A, B and C. The individual strains of this virus family differ in their protein composition and are constantly changing it. The strains are categorized according to the two proteins haemaglutinin (H) and neuraminidase (N), which also explains why the avian flu virus is also known as H5N1.
For this reason, one can be infected with the flu again and again and therefore a new vaccination is necessary every year, since the viruses have different characteristics. It should be noted that we are talking about the real flu, the influenza. Although flu-like infections (colds) are often colloquially also called flu, they are caused by completely different pathogens and are usually much more harmless.
Structure of the influenza virus
The genes of the influenza virus are located on eight individual RNA strands, which are virtually the heart of the virus. They contain all the information necessary for the replication of the virus and for the production of up to eleven proteins that are needed for the virus to function. Together with certain enzyme complexes, which are responsible for the conversion of genes into functional proteins, they are surrounded by a thin lipid envelope, also known as the virus membrane.
Up to this point, the virus can be imagined as a soap bubble. The virus membrane is intertwined by two types of proteins, haemagglutinin (HA) and neuraminidase (NA), which protrude from the “soap bubble” like spikes. HA enables the virus to attach itself to human cells and penetrate them in order to use their metabolic mechanisms as “parasites” – in contrast to bacteria, viruses must rely on this because they do not have their own metabolism. NA, on the other hand, has the function of enabling the newly formed viruses in the human cell to leave the host cell. This topic might also be of interest to you: Virus infection
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