H1 N1 History
Swine influenza was first proposed to be a disease related to human flu during the 1918 flu pandemic, when pigs became sick at the same time as humans. The first identification of an influenza virus as a cause of disease in pigs occurred about ten year later, in 1930. For the following 60 years swine influenza strains were almost exclusively H1 N1. Then, between 1997 and 2002 new strains of three different subtypes and five different genotypes emerged as causes of influenza among pigs in North America in 1997---1998, H3 N2 strains emerged. These strains, which include genes derived by resentment from human swine and avian viruses, have become a major cause of swine influenza in North American resentment between H1 N1 and H3 N2 produced H1 N1. In Canada, a strain of H4 N6 crossed the species barrier from birds to pigs but was contained on a single farm. 1918 pandemic in humans
The 1918 flu pandemic in humans was associated with H1 N1 and influenza appearing in pigs; this may reflect a zoonosis either from swine to humans or from humans to swine. Or from humans to swine. Although it is not certain in which direction the virus was transferred, some evidence suggests that, in this case, pigs caught the disease from humans. For instance, swine influenza was only noted as a a new disease of pigs in 1918 after the first large outbreaks of influenza amongst people. Although a recent phylogenetic analysis of more recent strains of influenza in humans, birds, and swine suggests that the 1918 outbreak in humans followed a reassortment event with in a mammal, the exact origin of the 1918 strain remains elusive. It is estimated that anywhere from 50 100 million people were killed worldwide.
1976 U.S. outbreak
On February 5, 1976 in the United States an army recruit at grot Dix said he felt tired weak. He died the next day and four of his fellow soldiers were later hospitalized. Two weeks after his death, heath offcials announced that the cause of death was a new strain of swine flu. The strain, a variant of H1 N1 variant of H1 N1 is known as A/New Jersey/1976(h1N10.It was detected only from January 19 to February 9 and did not spread beyond fort Dix. 1998 US outbreak in swine In 1998 swine flu was found in pigs in four U.S states. Within a year , it had spread through pig populations across the United States. Scientist found that this virus had originated in pigs as a recombinant form of flu strain from birds and humans. This outbreak confirmed that pigs can serve as crucible
