Influenza viruses, their classification and influenza vaccines

Influenza Classification (Health And Medical Video April 2018).

Article content:

  • Types of influenza viruses and their characteristics
  • Hazardous influenza A and B viruses for humans
  • Influenza A and B vaccine
  • The order of classification of different types of influenza

Types of influenza viruses and their characteristics

Modern medicine allocates only four types of influenza viruses: A, B, C and D.

  • The emergence of a new influenza A virus, which is very different from other types of influenza, may lead to a flu pandemic
  • Human influenza A and B viruses cause seasonal epidemics in Ukraine and in other countries of the northern hemisphere almost everywhere
  • Influenza Type C usually causes mild respiratory disease and in general is not able to cause an epidemic.
  • D-type influenza mainly affects cattle and this type of flu is not transmitted to humans.

Proceeding from this, the most dangerous for humans are viruses type A and B.

Hazardous influenza A and B viruses for humans

Type A viruses are divided into subtypes based on two proteins on the surface of the virus: - hemagglutinin (H) - neurominidase (N) There are 18 different hemagglutinin subtypes (H1 to H18) and 11 different neurominidase subtypes (from N1 to N11).

Group A influenza viruses can be divided into different strains. Current subtypes of influenza A viruses found in humans are influenza A (H1N1) and influenza A (H3N2). But in spring 2009, a new strain of influenza A (H1N1) was discovered. This strain of the virus was very different from the previous strain of influenza A (H1N1) and has caused the first flu pandemic in the last more than 40 years. This strain (often referred to as "2009 H1N1") has now replaced the previous strain A (H1N1), which was previously distributed in the world.

Influenza viruses B do not subdivide into subtypes, but can be broken into pedigree and strains. Currently, influenza A viruses, which belong to one of the two lines: B/Yamagata and B/Victoria, are common.

Influenza A and B vaccine

Influenza A (H1N1), A (H3N2) and one or two influenza B viruses (depending on the vaccine) are included in the annual influenza vaccine. Getting an influenza vaccine can only protect against those types of influenza viruses that are contained in the vaccine (or related to them). The seasonal flu vaccine does not protect against flu viruses C. In addition, the influenza vaccine does not protect against infections and diseases caused by other viruses, which can also cause flu-like symptoms. There are many other non-influenza viruses, but they can lead to flu-like illness (IHP).

The order of classification of different types of influenza

To avoid confusion in the names of different groups and strains of the influenza virus, there is an internationally recognized naming procedure for each type of influenza virus. To do this, in 1979 a special convention was adopted at the WHO. After that, in February 1980, it was published in the bulletin of the World Health Organization. According to this convention, influenza viruses are classified as follows:

  • By type of antigen (for example, A, B, C);
  • By the carrier of the virus (for example, swine flu, horses, chickens, etc. For viruses of human origin notation is not given);
  • By geographic origin (for example, Denver, Taiwan, etc.);
  • By the number of the strain (for example, 15, 7, and so on);
  • The year of isolation (eg 57, 2009, and so on);
  • For influenza A viruses, haemagglutinin antigens and neuraminidase are indicated in brackets (eg A (H5N1)).

For example: A/Duck/Alberta/35/76 (H1N1) - for the 35 strain of Dactyne A (H1N1) virus, which was discovered in the Alberta region and isolated in 1976. A/Perth/16/2009 (H3N2) - for the 16 strains of human A (H3N2) virus, which was discovered in the Perth region and isolated in 2009.



Influenza viruses, their classification and influenza vaccines

Category Of Medical Issues: Diseases

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