Health authorities have identified 14 “suspicious” cases of respiratory distress in the United States -- including one in Los Angeles -- that may be linked to a mysterious wave of infection emerging from Asia, but none of the cases has been definitively identified as the enigmatic illness, the Centers for Disease Control and Prevention said Monday.
Meanwhile, the agency has begun handing out cards at Los Angeles International and other airports to travelers arriving from Hong Kong and other Asian cities warning them to contact authorities if they develop influenza-like symptoms.
The World Health Organization has now identified 167 cases of the disease, called severe acute respiratory distress syndrome, or SARS, and nine deaths beyond those originally reported in China. Most of the cases have been in China, Hong Kong, Vietnam and Singapore, but eight cases have been found in Canada and one in Germany. Possible cases have been reported in Britain and Switzerland.
“We are taking this very seriously,” Tommy G. Thompson, secretary of the Department of Health and Human Services, said Monday. U.S. health authorities “are working around the clock” to look for other cases and to try to find the cause of the disease, he added.
“To date, we have not been able to identify any agent that can be linked to the outbreak,” he said.
The Los Angeles case is a man who was hospitalized last week after developing flu-like symptoms soon after returning from Asia, said Maria Iacobo, a spokeswoman for the Los Angeles County Department of Health Services. The man’s symptoms were never severe enough for him to have been placed on a ventilator, however, and he is “doing well,” she said.
Blood specimens have been sent to CDC for testing, but it now seems unlikely that he is suffering from SARS, experts said. Virtually all of those with confirmed cases of the disease have required mechanical ventilation. No other suspicious cases have been seen in California, said Leah Brooks of the state Department of Health Services.
The illness, which starts with flu-like symptoms such as coughing, high fever and shortness of breath, can deteriorate rapidly into severe pneumonia. The incubation period seems to be from two to seven days.
CDC chief Dr. Julie Gerberding said she doubted any of the 14 suspicious cases were linked to the outbreak. “It would not be surprising to identify cases in the United States, but we have not found any yet,” she said.
“The most important thing now is to prevent the spread,” she added, which is why health authorities are warning travelers about the potential danger. “The second-most important thing is to find out what is causing it.”
CDC labs and others are working hard to do so. “If it were a common organism, we would have found it by now,” she said. “It’s either very difficult to grow in the laboratory or it is an agent we have not had much experience with.”
Dr. James Hughes, director of the CDC’s National Center for Infectious Diseases, cautioned that it may take considerable time to identify the agent responsible. In the 1976 outbreak of Legionnaire’s disease, he noted, it took six months to find the bacterium responsible.
Gerberding noted that specimens from Asian patients are only now on their way to the CDC’s laboratory in Atlanta. “We are confident we will be able to identify the cause,” she said.
Although the unknown agent appears to be very infectious, new infections so far appear to be “limited to people who have had very close contact with those who are already infected,” she said.
Researchers believe it is transmitted primarily in droplets expelled during coughing and perhaps by transfer of bodily fluids. Many of the initial transmissions occurred among health-care workers who were not taking such precautions as wearing masks, gowns and face shields. The rate of transmission appears to have slowed dramatically since such measures have been instituted.