PARIS, France (AFP) — A virulent pneumonia, billed as a global health risk, claimed dozens more victims in Southeast Asia yesterday, as the first suspected cases surfaced in Europe and the United States stepped up medical surveillance.

As the tally of suspected infections nudged the 500 mark — nine of them fatalities — the gateways of international travel beefed up vigilance, seeking to identify and advise passengers and aircrew who could be carrying the mystery bug.

The illness causes flu-like symptoms of fever, wheezy breathing and fatigue but in some cases has inflicted fatal pneumonia.

The World Health Organisation has termed the illness Severe Acute Respiratory Syndrome (SARS) until an international detective effort, launched by lab sleuths in 10 countries, unmasks the agent that causes it, finds out how it spreads and determines its incubation period.

The disease “is not spreading as rapidly as influenza”, David Heymann, WHO’s executive director for communicable diseases said.

“A normal influenza would be very contagious to people sitting in the same room.”

His organisation issued a global health warning on the outbreak on Saturday, listing the afflicted countries as Canada, China, Hong Kong, Indonesia, Singapore, Taiwan, Thailand and Vietnam.

In Hong Kong yesterday, Health Secretary Yeoh Eng-kiong appealed for calm after the number of confirmed cases nearly doubled, from 42 the day before to 83, while a further 12 people were under observation.

“The figure is alarming,” Yeoh admitted, but stressed, “This is time for calm and not panic.”

Sixteen of the cases were medical students, while 23 were close relatives of patients, he said.

“Hong Kong is a safe place, and there is no sign that the disease has spread to the community,” Yeoh said.

Singapore set up a task force to monitor the outbreak as the number of detected cases rose to 21. Two were in serious condition with severe pneumonia, the head of the task force, Tan Chorh Chuan said.

In Vietnam, at least 48 people have been infected, medical sources said yesterday. The Vietnam News Agency reported that the authorities had mobilised 100 volunteers and set up a steering committee to oversee efforts to control the outbreak.

Malaysia urged its citizens to avoid travelling to areas afflicted by SARS “unless absolutely necessary”.

The WHO has pinned the apparent outbreak to February 26, when a 48-year-old US businessman was taken sick in Hanoi with flu-like symptoms, following a trip to Shanghai and Hong Kong.

There are now more than 190 confirmed or suspected cases of SARS with four known fatalities, according to a toll compiled by AFP from WHO figures and local sources.

But experts strongly suspect that SARS is the self-same agent that struck southern China’s province of Guangdong last month, infecting 305 people, five of whom died.

In Europe, meanwhile, the health authorities in Germany, Switzerland, Slovenia and Britain said they were treating seven Southeast Asian travellers for symptoms of the illness.

Two were a Singaporean doctor and his mother-in-law, who were in a full isolation ward in Frankfurt, along with the doctor’s wife; two were being treated after their arrival in Geneva; a sixth was in the Balkan republic of Slovenia, and had recently returned from a trip to Vietnam; and the seventh was a person being treated in Britain after arriving from Hong Kong.

In the United States, the US Centres for Disease Control (CDC) said it had activated emergency procedures to tighten health surveillance.

Among the measures, the CDC will probe any illness among travellers who passed through the United States after being potentially exposed to the agent. It is also preparing health alert cards to be given at airports to travellers returning from Southeast Asia.

Airlines and airports began to tighten up vigilance to identify passengers or crew with fever symptoms, among them Cathay Pacific and the European air hubs of Paris, Vienna, Zurich and Geneva.