More than 900 people died worldwide earlier this year from the viral respiratory illness, most of them in China, Hong Kong, Taiwan and Singapore, before authorities managed to contain it after an unprecedented collaboration between scientists, doctors and politicans.

SARS is characterised by a high fever, dry cough, breathing difficulties, and changes in chest X-rays indicative of pneumonia, according to the World Health Organisation (WHO).

Unlike other deadly disease which appeared at the end of the 20th century such as AIDS and the Ebola virus, the coronavirus which causes the atypical pneumonia is highly contagious.

Strict isolation and rigorous treatment is needed to bring the disease under control, and before its method of infection was fully understood, most SARS cases occurred either in hospital workers caring for SARS patients or their close family members.

As yet no vaccine exists, and health experts are fearful that it could spread at any time to Africa already hard hit by AIDS and other diseases such as malaria and tubercolisis as well as by famine, and where such strict treatment could be hard to enforce.

According to experts in the southern Chinese province of Guangdong, the epicentre of last winter's epidemic, one person could have infected up to 100 others.

The World Health Organisation said it is still unclear exactly where SARS originated although researchers have established that it is a coronavirus similar to the common cold.

There is speculation the virus may have jumped from animals to human in the exotic animal markets of southern China, where wild animals are frequently killed for food.

Antibiotics so far have appeared to be ineffective in battling the disease, although almost 90 percent of SARS patients have recovered with careful nursing.

TERRA.WIRE