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 continue to puzzle over 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 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.
"There's a lot we still don't know about this problem," said Gerberding, who added that the CDC is still examining new samples that recently arrived from overseas.
"It's very preliminary to say any individual is a case of SARS," she said. "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.
"We don't want people who haven't traveled to this region to be concerned about this problem, at least at this point in time," she 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.
He said the new disease reminds everyone of "the potential danger posed by emerging infectious diseases."
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.
"There is now a clue about what might be causing this," said Dr. David Heymann, WHO communicable diseases chief. "This clue will make it easier to diagnose patients."
But Gerberding and other experts cautioned that it's still too soon to be sure this is the culprit behind the mystery illness.
"The laboratories that have identified this virus are very good laboratories," Gerberding said. "But we don't at this point know what it means."
The virus was found in patients' nasal passages, she said, and "it hasn't yet been identified from any tissues or lung material or other specimens that would directly implicate it as the cause of the infection."
Paramyxovirus is from a virus group that includes common childhood illnesses, such as mumps and measles.
"My suspicion is it may be a new virus within that family," said Dr. Larry Anderson, a CDC virus expert.
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.
"It would suggest that it spread through the air-conditioning system, but you can't rule out person-to-person contact, since you don't know if they were even in the same room together," said Ronald Atlas, president of the American Society of Microbiology. "But everything says it is airborne."
Gerberding noted that none of the hotel staff became ill. She said that investigating how the guests interacted will offer additional clues to the degree of contagion and how it's spread.
For now, all health officials know is that at least two of the guests visited each other in the hotel; contact among the others is being investigated.