What is Swine Flu? Influenza virus H1N1

The swine flu is likely a descendant of the infamous “Spanish Flu” that
caused a devastating pandemic in humans in 1918–1919. Descendants of
this virus have persisted in pigs though direct transmission from pigs
(swine) to humans is rare.



The World Health Organization has confirmed that at least some of the
human cases are never-before-seen version of H1N1 strain of Influenza
Type A.



H1N1 is the same strain which causes seasonal outbreaks of flu in
humans on regular basis. But the latest strain of H1N1 is different: it
contains genetic material that is typically found in strains of the virus that
affect humans, birds and swine.



Flu viruses have the ability to swap genetic components with other
viruses, and it seems likely that the new version of H1N1 resulted from a
mixing of different versions of the virus, which may usually affect different
species, in the same animal host.