The World Health Organisation on Friday withdrew its warning against travel to Hong Kong and the southern Chinese province of Guangdong, saying the SARS (Severe Acute Respiratory Syndrome) outbreaks there were under control.

Despite the fact that Hong Kong is still the second-most affected SARS area outside mainland China, WHO said the rate of daily infections and the number of outstanding cases had dropped to within limits set for travel alerts.

The decision to remove the travel advisory, issued on April 2, was a huge relief for Hong Kong, a former British colony where the trade-reliant economy has suffered severely.

The decision came as Hong Kong announced two more SARS deaths, but only two fresh cases.

The illness, fatal in about 15 per cent of cases, is caused by a virus linked to the common cold and has no standard treatment. It is spread by coughing, sneezing or touching infected objects. Symptoms include a fever, dry cough and shortness of breath.

Taiwan 'Worrisome'

"While the daily numbers of new cases indicate the size of the SARS outbreak in Taiwan, which is worrisome, they do not suggest an explosive escalation in the number of cases, as both older and new cases are being reported together on a daily basis," the WHO said in a statement published on its Web site.

The new infections in Taiwan took the number of probable SARS cases there to 538, behind only China and Hong Kong, and followed a record daily increase of 65 cases on Thursday.

An American physician from the US Centres for Disease Control and Prevention, who was helping Taiwan battle SARS, was airlifted to the United States after he went down with SARS-like symptoms including a fever and muscle pain.

China reported three more deaths and another 20 infections, taking its totals to 303 deaths and 5,285 cases.

Canada was investigating four possible cases, a week after it was declared SARS-free.

Meanwhile, a top Hong Kong scientist said it was likely that SARS, which has killed nearly 700 people and infected more than 8,000 worldwide, jumped to humans from civet cats, considered a delicacy in southern China.

Civet cats have huge amounts of the virus in their stool and respiratory secretions, but are unaffected, Yuen Kwok-yung, head of the University of Hong Hong's microbiology department, said after releasing results of a study into the source of SARS.

The finding may help prevent another such epidemic through more hygienic methods of farming and slaughter, he said.