Pandemic 2009 H1N1 Influenza A Virus, best known by the misnomer “Swine Flu”, is a new strain of H1N1 first identified in 2009. This is actually the second worldwide pandemic involving H1N1, the first being the 1918 influenza epidemic.
The pandemic H1N1 virus is spread from person to person, much in the same way that other seasonal influenza viruses spread. It can be passed to other people by exposure to infected droplets expelled by coughing or sneezing that can be inhaled, or that can contaminate hands or surfaces.
This manifests itself as increased breathing difficulty and typically occurs 3–6 days after initial onset of flu symptoms. The symptoms of H1N1 flu are similar to those of other influenzas, and may include: