A handful of suspected cases of a deadly flu-like illness surfaced in new spots around the globe Monday, but medical experts said there "should not be panic" because the spread is not as aggressive as most forms of influenza.

There also were no new fatalities since the nine first reported when the World Health Organization issued its unusual global alert over the weekend. WHO officials said they were investigating suspicious cases in England, France, Israel, Slovenia and Australia, all of which previously had none.

Most of the 167 cases that have appeared in the past three weeks are health workers in Hong Kong, Vietnam and Singapore. China said 300 people had what appeared to be the same illness in an outbreak that began last November in Guangdong province.

In the United States, the Centers for Disease Control and Prevention was skeptical that the four cases it was looking into would be verified as "severe acute respiratory syndrome," or SARS, the name given the unidentified illness. The CDC already has ruled out 10 other suspicious cases.

Disease investigators said it could take weeks to determine the cause of the mysterious outbreak.

Experts believe that the most likely explanation for the respiratory illness is an exotic virus or -- the most feared scenario -- a new form of influenza.

However, WHO's communicable diseases chief, Dr. David Heymann, said the illness doesn't seem to spread as quickly a flu.

"It isn't contagious at the level of many other infectious diseases," he said. "A normal influenza would be very contagious to people sitting in the same room."

So far, experts say there is no evidence the infection spreads by casual contact, such as sitting next to somebody in an airplane.

"There should not be panic. This is a disease which, it seems, requires very close contact with patients and it is mainly hospital workers who have been infected in the first wave of infections. Now we are seeing that some other family members have been infected," Heymann said.

On the Net

CDC: www.cdc.gov/ncidod/sars