In March 2003, World Health Organisation scientist Dr. Carlo Urbani died in Bangkok when he was infected by a new virus that he was trying to stop spreading throughout the world. The disease, named Severe Acute Respiratory Syndrome (SARS) caused a fatal lung infection and created alarm across the globe.

SARS causes a severe lung infection that starts with symptoms similar to influenza (flu). It is caused by a new form of a Coronavirus that probably mutated inside a domesticated animal, such as a cat or chicken. After spreading it passed on to humans and the epidemic began. The outbreak originated in Southern China and within the space of eight months the virus had spread to over 24 countries including the USA, South America, Canada and Europe.

The first infections were seen in China in November 2002. By July 2003, when the last case was reported, the SARS virus had infected infected over 8,000 people and killed 813. Close monitoring is being maintained to make sure further outbreaks do not happen.

SARS starts with a high fever, headache, pains in the joints and an irritating cough. As the infection progresses, most patients develop pneumonia as the virus causes damage to the lungs. Fluid build-up and inflammation of the lungs cause breathing difficulties that have proved to be fatal in around 10% of those infected with the SARS virus.

Doctors in Hong Kong first noticed an increase in the number of people entering hospital with severe lung infections and medical investigators realised that many patients lived in the same apartment blocks. Health workers who had come into contact with infected patients also caught the disease. They realised that a new disease was spreading through the city and that action needed to be taken.

There is still a lot to learn about the SARS virus but researchers think that it can survive outside of the body for only a short time. Cleaning infected surfaces or clothes with soaps and bleaches will destroy the virus immediately.

Researchers looking at the Hong Kong outbreak realised that the virus could only be spread from person to person if there was close contact. The SARS virus was found in droplets of fluid from an infected persons cough or sneeze. The infection was spread if these droplets were inhaled or touched and transferred to a persons mouth or eyes.

Experts who study the spread of viruses recognised that SARS was actually quite a difficult virus to catch. Infections tended to be limited to those who lived with people infected by SARS or medical staff who came into close contact while treating them. However, the global reaction to SARS was quite phenomenal.

Modern travel means that viruses can spread around the globe very rapidly. Countries screened people arriving at airports for signs of fever, face masks in the streets of Hong Kong were common, hundreds were sent into quarantine and the world's economy suffered as fewer people travelled to areas that were affected by the virus. Was this an over-reaction or necessary precautions?

It is true to say that the SARS virus was successfully and quickly contained by many of the actions that were taken by health authorities around the world. However, in the time that SARS was making the headlines, over 1.5 million people were infected with influenza and this will have resulted in an estimated 125,000 deaths. Although influenza is a serious killer, it does not get the same media attention as the SARS outbreak received. Some would argue that more resources should be put into the containment and treatment of influenza.