How does this virus change over time What made this virus un

How does this virus change over time? What made this virus unique in 2009?

Solution

H1N1 virus causes influenza in humans. Influenza virus is constantly changing. They can change in two different ways: Antigenic drift and antigenic shift.

Antigenic drift: These are small changes in the genes of influenza virus that happens continually over time as the virus replicates. These small genetic changes usually produce viruses that are closely related to each other. Viruses which are closely related to each other in the phylogenetic tree shares same antigenic properties and an immune system exposed to a similar virus will recognise it and respond.

These small changes accumulate over time and results in viruses that are antigenically different. When this happens, body\'s immune system will not be able to recognise it.

Antigenic shift: It is an abrupt, major change in the influenza virus resulting in a new haemagglutinin and or new haemagglutinin and neuraminidase combination that has emerged from an animal population that is so different from the subtype in humans that most people do not have immunity to the new virus. Such a shift occurs in H1N1 virus in 2009.

The 2009 flu pandemic was an influenza pandemic invloving H1N1 influenza virus in a new version. Antigenic shift occurred in 2009, when a H1N1 virus with a new combination of genes emerge to infect people and quickly spread causing a pandemic. When shift happens, most people have little or no protection against the virus.