Swine influenza virus (SIV) is caused by Orthomyxoviruses that are endemic to pig populations. SIV strains isolated to date have been classified either as Influenzavirus C or one of the various subtypes of the genus Influenzavirus A. Swine flu, unlike bird flu, is able to pass from human to human contact. The 2009 swine flu outbreak is the spread of a new strain of H1N1 influenza virus that was first detected by public health agencies in March 2009. Local outbreaks of influenza-like illness were detected in three areas of Mexico, but the presence of this new strain was not discovered for a month. Following this discovery in the parts of United States bordering Mexico, its presence was swiftly confirmed in the local outbreaks in Mexico, and...