Atlanta ? Health officials said Wednesday that 11 suspected cases of a mysterious flu-like illness have emerged in the United States, while on the other side of the world, medical investigators continued to wonder how the illness spread in a Hong Kong hotel.

Centers for Disease Control and Prevention chief Dr. Julie Gerberding said the suspected U.S. cases are people who recently traveled to Asia and later developed fever and respiratory problems, matching definitions for the mystery illness, called “severe acute respiratory syndrome” or SARS.

The illness, for which there is no treatment, has caused 14 deaths, including five people who died months earlier in an outbreak in China.

The worldwide number of cases, including the 11 suspect U.S. cases, now totals 264, according to the World Health Organization. Most of those cases are in Hong King, Vietnam and Singapore. The WHO said Wednesday that they continue to receive reports about some patients recovering from the illness, which causes high fever and severe breathing problems.

“It’s very preliminary to say any individual is a case of SARS,” said Gerberding. “It is going to take some days to know for sure.”

She declined to say where the U.S. cases are, but health officials in New Mexico, California and New Jersey said they each had one case on the list.

In New Mexico, a patient from Albuquerque, who recently returned from Hong Kong, was in a hospital’s respiratory isolation unit, state health officials said Wednesday.

Los Angeles County’s public health officer said a man with SARS symptoms was recovering after being hospitalized Saturday. He fell ill March 11 after returning from a visit to Vietnam, Hong Kong and part of China.

The New Jersey case involved a 36-year-old woman who began complaining of fever and a cough more than a week before she traveled to Asia, state health officials said. She returned to the United States on March 2 and, her condition having worsened, was hospitalized. She was released Monday.

Although more cases could be identified in the United States, people who haven’t recently traveled to affected areas in Asia shouldn’t worry, Gerberding said.

Health and Human Services Secretary Tommy Thompson cited the mysterious bug in announcing the government’s plan to spend $100 million toward vaccines that would fight off new strains of flu.

So far, the mystery bug has not been identified as a new flu strain. Instead, health investigators are focusing on a family of viruses called paramyxovirus. First German, then Hong Kong doctors reported finding it in case specimens there. WHO said its labs will study other samples to see if the same virus is present.

But Gerberding and other experts cautioned that it’s still too soon to be sure this is the culprit behind the mystery illness.

Paramyxovirus is from a virus group that includes common childhood illnesses, such as mumps and measles.

Investigators said Wednesday that seven of the people infected, including one who died, all stayed on or visited the same floor of Hong Kong’s Metropole Hotel before the outbreak prompted a global alert. The discovery may be significant, because until now officials have said close personal contact is necessary to catch the illness.