The Origin of Swine Flu

The latest outbreak of disease causing hysteria in the media is that of Swine Flu. This disease, which is caused by a strain of the influenza virus termed H1N1, was initially believed to have originated in Mexico. This is mainly due to the fact that the earliest known case of human infection was in Mexico City. However, it is still unclear as to exactly how this disease was brought about.

In an attempt to determine H1N1’s true origins, its genome was sequenced and then compared to genomes of other influenza virus strains in order to determine how it is related to them. Fortunately, current medical research techniques allow the relatively small genomes of viruses to be sequenced very quickly. As a result of this investigation, it was showed that H1N1 was most closely related to North American avian flu and classical swine flu. However, it also displayed a resemblance to both the Eurasian swine and human influenza viruses.

Consequently, it is believed that the following situation resulted in the development of H1N1. Firstly, A U.S pig infected with the classical North American swine flu travelled to part of Asia, possibly as part of the hog trade. Here, it developed the ability to be transmitted from pig to human and subsequently did so. Finally, it is suggested that this person returned to North America, where the virus perfected human to human transmission and resulted in what is seen currently. One additional piece of information that also supports this theory is that the earliest cases of swine flu occurred in communities well known for migration.

Reference: http://www.sciencemag.org/cgi/content/full/324/5928/700