Since swine influenza infections typically present in humans as seasonal influenza, most of the cases are detected by chance through flu surveillance. Swine flu symptoms, similar to those of seasonal influenza may include:

The Federal Government has set up a swine flu hotline for public information: 1802007

The best way to protect yourself from swine flu is to avoid catching it in the first place. These simple measures can reduce your chances of picking up or spreading the virus.

• Avoid close contact with people who are sick. If you are sick, stay away from others to ensure they don’t get sick too.

• If you have flu symptoms, stay home. If people you work with have flu symptoms, encourage them to stay home. People who have symptoms should not go to work or school or to the shops. This will prevent other people from catching the illness.

• Cover your mouth and nose with a tissue when coughing or sneezing. Then throw the tissue away.

• Wash your hands frequently to keep them free from germs.

• Avoid touching your eyes, nose or mouth. This is one way the flu can be spread – by touching something that is contaminated with germs then touching your eyes, nose or mouth.

• Look after your general health. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids and eat well.

Adapted from information supplied by the US Coordinating Centre for Infectious Diseases

The World Health Organisation (WHO) uses a series of six phases of pandemic alert to inform the world of the seriousness of a particular threat. These are:

• Phase 1: No viruses circulating among animals have been reported to cause infections in humans

• Phase 2: An animal virus circulating among domesticated or wild animals is known to have caused infection in humans, and is therefore considered a potential pandemic threat

• Phase 3: An animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks

• Phase 4: Verified human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause 'community-level outbreaks'

• Phase 5: Human-to-human spread of the virus into at least two countries in one WHO region. A strong signal that a pandemic is imminent and the time to finalise the organisation, communication, and implementation of the planned mitigation measures is short.

• Phase 6: Community-level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Global pandemic is underway.

(Source: WHO)

1918 Spanish flu

• The worst pandemic of the 20th century

• Was a particularly virulent and deadly H1N1 strain

• Like swine flu, it affected mostly young, otherwise healthy adults

• Up to 40 per cent of the world’s population fell ill with the virus

• The World Health Organisation estimates it killed 50 million people – more than died in WWI

• More recent estimates of the death toll, taking into account areas where deaths were unlikely to be reported, come in at 100 million

1957 Asian flu

• Began in China and saw the spread of the H2N2 strain of flu

• Came in two wave – the first hit children, the second elderly people

• Around 2 million people died

1968 Hong Kong flu

• Mild by previous standards

• Began when H2N2 mutated to create H3N2

• Still resulted in almost 1 million deaths worldwide