Swine influenza is referred to such kind of flu which is caused by influenza virus endemic in pigs. Mostly, strains endemic in swine are known as swine influenza virus. It is known to everyone that there are three forms of human flu from which two are endemic in swine. Usually Influenza virus A is most commonly flue and Influenza virus B is not found in swine. On the contrary influenza virus C is the rarest form.

It is an undeniable fact that Swine flu is most common in swine and rare in humans. Mostly those people get affected by it who work with swine specially those who have greater exposure to swine are at higher risk of having swine influenza. In majorit of cases, those people are affected who worked with those swine which carried a strain having the ability to infect humans. These strains not usually circulate in human blood as SIV and get chances to pass easily from human to human. The most common symptoms include chills, fever, sore throat, headache, coughing, weakness and chronic fatigue.

Background of Swine Flu

The first swine flu case was registered in Military hospital during Spanish flu pandemic in 1918. It caused a worst and destructive pandemic in humans. Though it persists in pigs commonly, but the descendants of 1918 virus have circulated in humans by the 20th century which enhanced the normal seasonal epidemics of influenza. Since 2005, only 12 cases are registered in U.S in which there was direct transmission from pigs to human. Recently, the causes of 2009 flu in humans is only due to a new strain of influenza A virus subtype H1N1. The origin of this new strain is still undiscoverable. It is also observed by the World Organization for Animal Healty (OIE) that this type of flue has not been isolated in swine. Swine flu transfers from human to human through unidentified mutation. In this form of flue, an infected person can get full recovery by earlier diagnosis and proper treatment without the use of antiviral medicines.

In 1957, an Asian flu pandemic caused 70,000 deaths and infected more than 45 million Americans. After eleven years, the Hongkong pandemic infected 50 million Americans and killed 33,000 deaths which did cost more than $3.9 billion. In 1976, more than 500 soldiers became inflicted with swine flu over a period of a few weeks. Surprisingly, by the end of the month, researchers found that there is no sign of flue anywhere anymore and it vanished astonishingly.

To the medical science, the flu virus is the most complicated phenomenon due to many constantly changing symptoms. It gets changing form to elude the saviour antibodies which the body has already developed against previous exposure to influenza or to influenza vaccines. These researchers found that swine flu virus mutate into something as deadly as the Spanish flu and making global plans to remove this pandemic.

Classification of Swine Flu

Commonly, swine flu is classified into two types.

The is most common cause of Swine Influenza. Throughout the world, Influenza A subtype (H1N1, H3N2, and H1N2) are circulating. The second type of swine flu is H5N1 influenza virus. It is H3N2 which is endemic in pigs in China. It has been noted that it is detected in pigs in Vietnam. In August 2004, H5N1 was found in pigs in China.