As you are aware, different species harbor different strains of the flue virus. In course of time, these viruses mutate causing small changes to proteins on their surface called antigens. If our immune system meets some particular strain of the virus before it gathers immunity and if the antigens are new, it is possible that our immune system may not be able to respond well. Some of the antigens involved in the new strain have never been seen by the immune systems of almost all humans, so the new strain has the potential to cause a pandemic.
In the past we have already seen flu pandemics. In 1918, the Spanish flu pandemic caused by a form of the H1N1 strain of flu, remains the most devastating outbreak of modern times. It is estimated that up to 40% of the world’s population were infected, and more than 50 million people died, with young adults particularly badly affected. In 1957, Asian flu caused by a human form of the virus, H2N2, combining with a mutated strain found in wild ducks killed two million people,. The impact of the pandemic was minimised by rapid action by health authorities, who identified the virus, and made vaccine available speedily. The elderly were particularly vulnerable. In 1968, an outbreak caused by a strain known as H3N2 was first detected in Hong Kong and killed up to one million people globally,
The flu currently making headlines is a strain of H1N1 influenza A virus, which affects birds, some mammals and humans.It is a new version of the H1N1 strain which caused the 1918 flu pandemic. 
Most cases of Swine Flue are being reported from around the world to have mild infections but since more than 100 patients have died in Mexico due to this flue, it has become a matter of serious concern world over.The World Health Organization has confirmed that at least some of the human cases are a never-before-seen version of the H1N1 strain of influenza type A. It has further warned that taken together the Mexican and US cases could potentially trigger a global pandemic, and stress that the situation is serious. However, experts say it is still too early to accurately assess the situation fully because the severity of the Mexican outbreak may be due to an unusual geographically-specific factor – possibly a second unrelated virus circulating in the community – which would be unlikely to come into play in the rest of the world. It may also be the case that the form of the virus circulating in Mexico is subtly different to that elsewhere – although that will only be confirmed by laboratory analysis.
Since the new virus, appearing to be a genetic mix of swine, avian and human flue strains, has made the jump from pigs to humans and has demonstrated it can pass quite easily from human to human, it is demanding so much attention from worldwide health authorities. The virus passes from human to human like other types of flu, either through coughing, sneezing, or by touching infected surfaces. Actually it is a respiratory disease, caused by influenza type A which originally infects pigs. There are many types, and the infection is constantly changing. Until now it has not normally infected humans, but the latest form clearly does, and can be spread from person to person – probably through coughing and sneezing.
As initial symptoms like fever, cough, sore throat, body aches, chills and fatigue are similar to seasonal flu, usual treatments do work, but there is no specific vaccine. We hope that, as humans are often exposed to forms of H1N1 through seasonal flu, our immune systems may have something of a head start in fighting infection. However, the fact that many of the victims are young does point to something unusual. Normal, seasonal flu tends to affect the elderly disproportionately.
For seasonal flue, normally two drugs, Tamiflu and Relenza are taken and they seem to be effective at treating cases that have occurred there so far. However, the drugs must be administered at an early stage to be effective. It is also expected that the use of these drugs may also make it less likely that infected people will pass the virus on to others. It is yet to be examined how effective currently available flu vaccines would be at offering protection against the new strain, as it is genetically distinct from other flu strains.
We may take some precautions like:
1. At individual level, anyone with flu-like symptoms who might have been in contact with the swine virus – such as those living or travelling in the areas of Mexico that have been affected – should seek medical advice immediately.
2. The affected person must stay at home and call their health care provider at home for advice. He/she must not go out in order to minimise the risk of spreading the disease to others.
3. We must avoid close contact with people who appear unwell and who have fever and cough.
4. Good personal hygiene practices, such as washing hands, covering nose when sneezing are advised. They can help to reduce transmission of all viruses, including the human swine influenza. This includes covering your nose and mouth when coughing or sneezing, using a tissue when possible and disposing of it promptly.
5. It is also important to wash your hands frequently with soap and water to reduce the spread of the virus from your hands to face or to other people and cleaning hard surfaces like door handles frequently using a normal cleaning product.
6. If caring for someone with a flu-like illness, a mask can be worn to cover the nose and mouth to reduce the risk of transmission.
7. Though there is no evidence that swine flu can be transmitted through eating meat from infected animals, it is essential to cook meat properly. A temperature of 70C (158F) would be sure to kill the virus.
8. We must create public awareness to avert the swine flue to take shape of another pandemic. 
Be Happy and take precautions against Swine flu for the welfare of all.