SARS stands for severe acute respiratory syndrome, and is a life threatening respiratory illness that is caused by a virus known as the SARS coronavirus, or SARS CoV.
SARS is spread in the same way as colds and flu - through the air in droplets from coughs and sneezes, and through contact with contaminated surfaces. It is also believed to spread through contact with an infected person's faeces, for example if they fail to wash their hands thoroughly after going to the toilet they may contaminate other things they touch.
There have been four probable cases of SARS recorded in the UK, thought to have been caused by infected air passengers.
Public Health England says SARS was first recognised as a threat to health in China's Guangdong Province in 2002.
The spread of the virus in that epidemic reached North America but was contained in 2003, and the last reported outbreak was in 2004, according to the World Health Organisation.
Symptoms of SARS
The main symptoms of SARS are:
- High fever (over 38°C)
- Flu-like symptoms
- Dry cough
- Shortness of breath or difficulty in breathing
- Chest X-rays may show the signs of pneumonia
Although more serious than seasonal flu, SARS appears to be less infectious than flu.
SARS has an incubation period of around two to 10 days, so tracing people who have been in contact with an infected person can be difficult.
SARS cannot yet be cured, but research is continuing into ways of protecting against it such as vaccines.
Around 4%-10% of people with probable SARS infections die from it.
In the event of a SARS outbreak, wearing a mask or respirator is just one way to prevent the spread of SARS for frontline healthcare workers. Masks are not recommended for travellers, though good personal hygiene, especially hand hygiene, is known to help reduce the spread of the virus.
Preventing and eradicating SARS is the subject of a UN resolution.
SARS research work has to be carried out under tightly controlled conditions to prevent scientists being infected during their investigations.
Investigations into the 2004 outbreak centred on the National Institute of Virology in Beijing where experiments on the SARS virus were carried out.
If someone is believed to be carrying SARS, countries around the world - including the UK - have emergency health plans that involve isolating the person to prevent the infection from spreading.
SARS does not currently present a threat to health for travellers, but scientists and the World Health Organisation remain on alert for any cases, or signs of the virus mutating.
In the event of new outbreaks of SARS, the Foreign Office would issue health advice to travellers.