Swine flu is a pervasive disease that has been impacting large number of people in America. This disease is mainly caused due to a certain influenza virus commonly referred to as Swine Influenza Virus (SIV).
It is a widespread ailment that usually attacks pigs and reportedly; pigs of several American regions like South America, Mexico and Canada are infected by it.
Origins Of The Disease
Recently, several theories about the spread and origin of swine flu have been propounded. The most common belief is that this flu-type saw its beginnings in the year 1930 in the United States.
However, there were cases of a similar disease that became visible around 1918. During the flu-epidemic in 1918, this ailment was projected as a virus co-related to human influenza.
Several cases of pigs falling ill along with humans were reported during this period.
Generally, medical history shows that swine flu is caused by certain categories of influenza. Mostly, this sickness is rooted into Influenza —A category and its subtypes — H1N1, H1N2, H2N3 and H3N2.
The subtypes that infect pigs are H3N2, H1N1 and H1N2. After 1930, H1N1 viral-strain was the most prominent factor in causing this illness among pigs within the next few decades.
Medical researchers considered the possibility of a ‘zoonosis’ from humans to pigs or vice-versa during this 1918 flu-outbreak.
‘Zoonosis’ is referred to as an infectious illness which can be transferred from different animals (vertebrate creatures) to humans or vice-versa.
Although it was not confirmed which course did this influenza take, (animal to human or reverse order) during the 1918 flu; some data implies that the pigs caught the virus from the humans back then.
However, the exact origin of the 1918 flu is still a mystery.
Chronology That Followed The First Outbreak
In 1976, another major eruption of the swine flu emerged in Fort Dix, New Jersey where four soldiers contracted the disease.
One died among the group and two weeks after his demise, medical practitioners announced that a new viral-strain of the flu caused his death.
This viral-strain appeared very familiar to the one that caused pig and human death in 1918. This 1976-strain was called ‘A/New Jersey/1976 (H1N1).’
Around this time, came the awareness within the medical community and efforts were made for mass-vaccination programs.
However, in the year 1988, a ‘zoonosis’ of the flu was witnessed yet again when a Wisconsin lady died because of it. Swine flu also spread out to hundreds of other people.
Between the years 1997 and 2002, 3 latest viral-strains of the influenza subtypes and five diverse genotypes were discovered as the primary reason for flu among pigs in North America.
In 1998, pigs across states in America were attacked by this flu in huge numbers. Researchers confirmed that the virus infesting these pigs was a blended structure of viral-strains from humans and birds.
In 2007, this flu-type was once again detected in Philippines. The most recent strains of influenza were noticed during the 2009 swine flu endemic in Mexico and some farm pigs in Alberta, Canada.