Pandemic Influenza

Virus name and origin

The origin of this new virus is not known, but based on genetic analysis it appears to have been created by mixing of genes from two different swine influenza viruses as well as an avian influenza and a human influenza virus.  Scientists call this a "quadruple reassortant" virus.  It was initially called ‘swine influenza’ because most of its genes come from swine influenza, but this name gives the misleading impression that pigs are involved in transmission. They are not.  It is important to emphasize that this new H1N1 virus is now fully adapted to humans.

The above animation depicts the probable sequence of re-assortments leading to the novel Influenza-A/H1N1 which is currently circulating in North America and which has already spread to other parts of the world.