
Swine influenza (also swine flu) refers to influenza caused by any virus of the family Orthomyxoviridae, that is endemic to pig (swine) populations. Strains endemic in swine are called swine influenza virus (SIV), and all known strains of SIV are classified as Influenzavirus A (common) or Influenzavirus C (rare).Influenzavirus B has not been reported in swine. All three classes, Influenzavirus A, B, and C, are endemic in humans].
People who work with poultry and swine, especially people with intense exposures, are at risk of infection from these animals if the animals carry a strain that is also able to infect humans. SIV can mutate into a form that allows it to pass from human to human.
The strain responsible for the 2009 swine flu outbreak is believed to have undergone this mutation.[2]
In humans, the symptoms of swine flu are similar to those of influenza and of influenza-like illness in general.
The swine flu is susceptible to four drugs licensed in the United States, amantadine, rimantadine, oseltamivir and zanamivir, however, for the 2009 outbreak it is recommended it be treated under medical advice only with oseltamivir and zanamivir to avoid drug resistance.[The vaccine for the human seasonal H1N1 flu does not protect against the swine H1N1 flu, even if the virus strains are the same specific variety, as they are antigenically very different
Swine flu in humans
People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur.[Transmission of influenza from swine to humans who work with swine was documented in a small surveillance study performed in 2004 at the University of Iowa.This study among others forms the basis of a recommendation that people whose jobs involve handling poultry and swine be the focus of increased public health surveillance.[The 2009 swine flu outbreak is an apparent reassortment of several strains of influenza A virus subtype H1N1, including a strain endemic in humans and two strains endemic in pigs, as well as an avian influenza
The CDC reports that the symptoms and transmission of the swine flu from human to human is much like that of seasonal flu. Common symptoms include fever, lethargy, lack of appetite and coughing, while runny nose, sore throat, nausea, vomiting and diarrhea have also been reported.It is believed to be spread between humans through coughing or sneezing of infected people and touching something with the virus on it and then touching their own nose or mouth.
Swine flu cannot be spread by pork products, since the virus is not transmitted through food.The swine flu in humans is most contagious during the first five days of the illness although some people, most commonly children, can remain contagious for up to ten days. Diagnosis can be made by sending a specimen, collected during the first five days, to the CDC for analysis.[
The origins of this new strain remain unknown. One theory is that Asian and European strains traveled to Mexico in migratory birds or in people, then combined with North American strains in Mexican pig factory farms before jumping over to farm workers.[The earliest known human influenza A virus subtype H1N1 case was at a Mexican pig farm whose nearby neighbors had been complaining about the manure smell and flies.]
Edgar Hernandez, 4, was suffering from ordinary influenza but laboratory testing has since shown that he had contracted human influenza A virus subtype H1N1. The boy went on to make a full recovery.
The Mexican health agency acknowledged that the original disease vector of the virus may have been flies multiplying in manure lagoons of pig farms near Perote, Veracruz, owned by Granjas Carroll,[a subsidiary of Smithfield Foods.
The CDC recommends the use of Tamiflu (oseltamivir) or Relenza (zanamivir) for the treatment and/or prevention of infection with swine influenza viruses. The virus isolates that have been tested from the US and Mexico are however resistant to amantadine and rimantadine.[If a person gets sick, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms).
Influenza A virus subtype H1N1
H1N1 is a subtype of influenzavirus A and the most common cause of influenza in humans. Some strains of H1N1 are endemic in humans, including the strain(s) responsible for the 1918 flu pandemic and the many strains that cause influenza worldwide each year. Other strains of H1N1 are endemic in pigs and in birds. The 1918 flu pandemic killed 50–100 million people worldwide from 1918 to 1919.[
In the name H1N1 the "H" refers to the hemagglutinin protein, and the "N" refers to the neuraminidase proteinLow pathogenic H1N1 strains still exist in the wild today, causing roughly half of all flu infections in 2006.[]
In March and April 2009, an outbreak of influenza-like illness in Mexico killed nearly 200 people, and in 20 of these people a new strain ofH1N1 was detected.[As of April 27, the new strain was suspected to have infected more than 2,000 individuals worldwide (see 2009 swine flu outbreak). On April 27, 2009, the World Health Organization raised alertness from level 3 to level 4
Interesting links
2009 swine flu outbreak in the United States - Wikipedia, the free encyclopedia

Tamiflu. is currently marketed by Hoffmann-La Roche (Roche) and was developed by US-based Gilead Sciences
Gilead Sciences was originally formed under the name of "Oligogen, Inc." in August 1987 by Michael Riordan, a medical doctor who was 29 years old at the time. But the name of the company was changed to "Gilead Sciences" in 1988. Riordan looked to DonaldRumsfeld as a mentor in the business world and to navigate the political waters.
In January 1997, DonaldRumsfeld, a Board member since 1988, was appointed Chairman of the company.[He stood down from the Board in January 2001 when appointed Secretary of Defense at the start of George W. Bush's first term as President. Federal disclosure forms indicate that Rumsfeld owns between USD$5 million and USD$25 million in Gilead stock. The rise in Gilead's share prices from USD$35 to USD$57 per share will have added between USD$2.5 million to USD$15.5 million to Rumsfeld's net worth.[3]
In November 2005, George W. Bush urged Congress to pass $7.1 billion in emergency funding to prepare for the possible birdflu pandemic, of which one billion is solely dedicated to the purchase, and distribution of Tamiflu.
UPDATE 3-Flu a windfall for some drugmakers, shares jump