How Influenza Virus Changes Its Antigenic Structure?

The video above is showing that how the influenza virus has changed its antigenic structure was published by The Associated Press News Agency two weeks ago and I wanted to share it with you. Influenza viruses are fast changing artists. They are constantly mutated and frequent changes make it difficult for our body to recognize the virus and develop an immune response to it. The animation explains why we need a new flu vaccine every year.

Influenza A viruses are subdivided on the basis of two proteins on the virus surface: hemagglutinin (HA) and neuraminidase (NA). There are 18 known HA subtypes and 11 known NA subspecies. Many different combinations of HA and NA protein are possible. For example, an "H7N2 virus" refers to an influenza A virus subtype that has an HA 7 protein and an NA2 protein. Similarly, a "H5N1" virus has an HA 5 protein and an NA1 protein.





All known subtypes of influenza A viruses can be transmitted to birds, except for the H17N10 and H18N11 subspecies found only in bats. There are currently only two influenza A virus subtypes (ie H1N1 and H3N2) in the general circulation of humans. Some subtypes are found in other infected animal species. For example, H7N7 and H3N8 virus infections can cause diseases in horses and H3N8 virus infection can cause disease in horses and dogs (source link >> Influenza Type A Viruses | Avian Influenza (Flu) - CDC).

Bird Flu (Avian Influenza, Avian Flu), H5N1 is a type of influenza virus that causes severe respiratory disease in birds called avian flu. H5N1 bird flu cases are occasionally seen, but it is difficult to infect humans. Almost all cases of H5N1 infection in humans have been associated with close contact with infected living or dead birds or environments contaminated with H5N1. The virus does not spread easily to people and the person-to-person spread seems unusual. There is no evidence that the disease has spread to people through properly prepared and thoroughly cooked foods (source link >> WHO | FAQs: H5N1 influenza).

 

Murat Enoz, MD, Otorhinolaryngology, Head and Neck Surgeon - ENT Doctor in Istanbul

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