Cases of a new deadly strain of pneumonia that originated in Asia are increasing and spreading around the world. In Hong Kong, one of the worst affected cities, the outbreak has forced one hospital to partially close.
The World Health Organization is putting more resources behind tracing the origin of the illness.
An illness the World Health Organization calls a "new communicable disease" is spreading from Asia to other continents, including Australia, North America, and Europe.
The WHO said it is boosting resources to investigate the agent causing the disease, which is a severe form of atypical pneumonia. The United Nations agency says 11 laboratories in 10 countries are investigating.
Called "Severe Acute Respiratory Syndrome," experts believe it originated in Asia and may have caused as many as nine deaths so far. The first cases were reported in southern China in February, with others following last week in Vietnam and Hong Kong.
News reports said one WHO expert who had visited patients in Hanoi became ill with atypical pneumonia enroute to Bangkok.
Experts said the agent causing the disease has proven very difficult to identify, but is characterized by its predilection to hit health care workers in close contact with patients.
While the WHO issued a rare travel advisory, one of the agency's spokesman told VOA that the illness spreads more slowly than most influenzas.
Peter Cordingley is an information officer based in Manila. "One of the interesting comparisons is that, quite clearly, it does not move as fast as flu does," he said.
In Hong Kong, health authorities warn that the city's outbreak has not yet peaked. One hospital is treating more than 50 patients, most of whom are hospital staff. It is shutting down many of its services due to lack of manpower.
"This is a virus we take very seriously," said Yeoh Eng-Kiong, Hong Kong's Secretary of Health. "It seems to cause pneumonia in a lot of the health care staff that are exposed. From the initial very limited experience it does seem that some of the drugs we are giving gives us at least a glimmer of hope."
At least 123 patients have symptoms associated with the disease in Hong Kong. And more than 110 have been diagnosed with atypical pneumonia - at least 30 more than the number reported on Monday. It reportedly has killed one person in Hong Kong and five in mainland China.
Australian authorities reported 20 suspected cases of atypical pneumonia. Switzerland confirmed two cases, while doctors in Israel, Britain, the United States, Canada, Germany and France are monitoring patients with symptoms.