Swine flu is a respiratory disease, caused by influenza type A which normally infects pigs. Symptoms of swine flu in humans are similar to those produced by standard, seasonal flu. These include fever, cough, sore throat, body aches, chills and fatigue. The latest form of Swine flu (Mexico 2009) can be spread from person to person. This version of the virus is H1N1 but contains genetic material that is typically found in strains of the virus that affect humans, birds and swine.
Three times in the last century, influenza viruses have undergone major genetic changes resulting in global pandemics that had devastating effects (Kawaoka 2006 Influenza Virology: Current Topics). The most infamous pandemic was the “Spanish Flu” which affected up to 25% of the world population and is thought to have killed at least 40 million people in 1918-1919 (Taubenberger and Palese, 2006 The Origin and Virulence of the 1918 ‘Spanish’ Influenza Virus). More recently, two other influenza pandemics, the “Asian Flu” in 1957 and the “Hong Kong Flu” in 1968, killed millions of people worldwide. These caused severe disease, not only in the young and the elderly, who are usually very susceptible to influenza, but also among healthy younger persons.