Swine flu - Prevention, Signs, Symptoms and treatment

Swine flu is a respiratory disease, caused by influenza type A which infects pigs.

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.

A declaration by U.N. health officials that will speed vaccine production and spur government spending to combat the first global flu epidemic in 41 years. Thursday's announcement by the World Health Organization doesn't mean the virus is any more lethal - only that its spread is considered unstoppable. Since it was first detected in late April in Mexico and the United States, swine flu has reached 74 countries, infecting nearly 29,000 people. Most who catch the bug have only mild symptoms and don't need medical treatment. WHO chief Dr. Margaret Chan made the long-awaited declaration after the U.N. agency held an emergency meeting with flu experts and said she was moving to phase 6 - the agency's highest alert level - which means a pandemic is under way.

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.

H1N1 is the same strain which causes seasonal outbreaks of flu in humans on a regular basis.

But this latest version of H1N1 is different: it contains genetic material that is typically found in strains of the virus that affect humans, birds and swine.

Flu viruses have the ability to swap genetic components with each other, and it seems likely that the new version of H1N1 resulted from a mixing of different versions of the virus, which may usually affect different species, in the same animal host.

Pigs provide an excellent 'melting pot' for these viruses to mix and match with each other.

Symptoms of swine flu are similar to those of seasonal flu and typically include a feverish illness, cough, sore throat, headache, fatigue, loss of appetite and muscle aches. Some people have reported diarrhoea and vomiting. In young children, warning signs include fast or troubled breathing, a bluish skin tone and irritability.

What measures can I take to prevent infection?

Avoid close contact with people who appear unwell and who have fever and cough.

General infection control practices and good hygiene 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.

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.

If caring for someone with a flu-like illness, a mask may be worn to cover the nose and mouth to reduce the risk of transmission. The UK is looking at increasing its stockpile of masks for healthcare workers for this reason.

In Mexico masks have been handed out to the general public, but experts are sceptical about how useful this is.

>> Avoid contact with other people as much as possible
>> Cover your nose and mouth when coughing or sneezing, using a tissue when possible
>> Dispose of dirty tissues promptly and carefully
>> Wash your hands frequently with soap and water to reduce the spread of the virus from your hands to your face or to other people
>> Clean hard surfaces, such as door handles or telephones, regularly using a normal cleaning product
>> Contact your local government hospital for proper management.

If you've developed symptoms, wearing a mask can help prevent you passing the infection onto others. If you're healthy, however, there's no scientific evidence to suggest that wearing one will prevent you from catching the virus. If you do decide to wear a face mask, make sure you wash your hands thoroughly when you take it off and dispose of it straight away. Reusing a face mask can increase the risk of self-contamination.

Monitor your health for seven days, but you don�t need to be isolated from other people. If you develop a feverish illness during that time, along with any of the other symptoms listed above, contact your local government hospital. Make sure you tell them where you had travelled to.

If your doctor decides further investigation is needed, he or she will advise you on what to do. You may have to go to hospital for tests, but most people are well enough to stay at home. Make sure you avoid contact with other people as much as possible until the results of your tests are back. People who live with you should also monitor their health and follow the above advice if they start to develop symptoms.

Yes. There is no evidence that swine flu can be transmitted through eating meat from infected animals.

However, it is essential to cook meat properly. A temperature of 70C (158F) would be sure to kill the virus.

Experts are also stressing that this is now a disease which is being passed between people.

The World Organisation for Animal Health said culling pigs, as Egypt has proposed, was therefore "inappropriate" as a measure to stop swine flu spreading.

It added there was no evidence of infection in pigs, nor of humans acquiring infection directly from pigs.

The strain of bird flu which has caused scores of human deaths in South East Asia in recent years is a different strain to that responsible for the current outbreak of swine flu.

The latest form of swine flu is a new type of the H1N1 strain, while bird, or avian flu, is H5N1.

Experts fear H5N1 holds the potential to trigger a pandemic because of its ability to mutate rapidly.

Those humans who have been infected have, without exception, worked closely with birds, and cases of human-to-human transmission are extremely rare. There is no suggestion that H5N1 has gained the ability to pass easily from person to person.

HOW SWINE FLU OUTBREAK EMERGED

: Flu viruses mutate over time causing small changes to proteins on their surface called antigens. If the immune system has met a particular strain of the virus before, it is likely to have some immunity; but if the antigens are new to the immune system, it will be weakened.