SARS is a viral
infection that causes symptoms including high fever and breathing difficulties. It hit the headlines as it
spread around the world in 2003.
What is it?
SARS, or severe acute
respiratory syndrome, a potentially fatal respiratory
infection, first appeared in the Guangdong province of China in November 2002, although it wasn''t reported to the World Health Organisation (WHO) at that time.
Then a Chinese professor of respiratory medicine treating people with the syndrome fell ill. He travelled to Hong Kong, carrying the virus with him. This led to an explosion of cases in the province towards the end of February 2003.
In just a few weeks, thanks to international air travel, SARS spread around the world. It wasn''t until July 2003 that the WHO was able to declare that the outbreak had been contained. By this time, at least 8,098 people had been infected, 9.6 per cent of whom had died.
Between July 2003 and May 2004, four small and rapidly contained outbreaks of SARS were reported. Three of these were linked to laboratory releases of the SARS virus.
What''s the cause?
It took scientists several months to pin down the cause of SARS, but eventually it was identified as a viral infection with a previously unknown type of coronavirus now known as SARS CoV.
Coronaviruses cause infections of the upper respiratory tract and are spread like the common cold. They are also quite tough and can survive in the environment for three hours.
Most new infectious diseases in humans come from animals, and this is thought to be the case with SARS. SARS CoV has been found in Himalayan palm civets, a racoon dog and a Chinese ferret badger. It has also been detected among people working in a live animal market in the area where the outbreak first began, and high levels of antibody to the virus have been found in people trading masked palm civets.
What are the symptoms?
The main symptoms of SARS are:
High fever (above 38°C)
Dry cough
Breathing difficulties
Headache
Muscular aches and stiffness
Loss of appetite
Malaise or tiredness
Confusion
Rash
Diarrhoea
These symptoms are typical of many severe respiratory infections. There have only ever been a few cases of SARS reported in the UK, so if you have symptoms like these it''s far more likely to be a more typical form of pneumonia. Even if you''ve recently returned from south-east Asia, there''s little risk that you have SARS as the virus has been contained.
How can I prevent it?
You''re unlikely to catch SARS. For it to spread there must be close contact with an infected person. It''s less infectious than flu, and has a short incubation period of two to seven days. People with SARS are most likely to be infectious once they have active symptoms of the disease, such as fever and cough. However, it''s not known how long before or after symptoms begin that a person remains infectious.
Although SARS is currently contained, people travelling to the area where it first appeared may want to check with the World Health Organisation or Foreign & Commonwealth Office for the latest advice.
Anyone who develops serious illness or breathing problems with fever and cough, especially after travelling abroad, should get urgent medical advice.
What''s the treatment?
So far, no specific treatment appears to be especially effective against SARS. Antiviral drugs such as ribavirin (given with or without steroids) were used in a number of cases in the 2003 outbreak, although it isn''t clear how effective they were.
With supportive care, the majority of patients started to show improvement by day six or seven of infection. About ten per cent of patients got rapidly worse and needed mechanical help (that is, a ventilator) to breathe. In this group, other illnesses tended to complicate the infection and it was more likely to prove fatal.