More SARS cases investigated in U.S.
ATLANTA, Georgia (CNN) -- The Centers for Disease Control and Prevention said Friday it is investigating 22 suspected cases in the United States of the mystery pneumonia from Asia that does not seem to respond to common treatments and whose cause is not known.
In some of those cases, the patients appear to have been infected while in the United States, rather than while abroad, CDC Director Julie Gerberding told reporters.
The World Health Organization is reporting 337 cases of Severe Acute Respirator Syndrome in 14 countries, including 10 deaths, she said. The WHO figures do not include the U.S. cases.
No deaths have been reported in the United States, Gerberding said.
Though the disease appears to have originated in Asia, some of the U.S. cases involve "secondary transmission" -- spread of infection from someone who returned from Asia to someone who had not left the country, Gerberding said.
In one case, a sick person appears to have infected two health care workers, and in another an infected person may have infected a family member, she said.
"Spread to contacts of travelers with this illness may be occurring in the United States," she said.
Among the 22 suspected U.S. cases are two Americans who stayed at a hotel in Hong Kong that has been implicated as the initial source of the spread -- "the place where almost all the international cases appear to have been exposed, in February," she said.
The Hong Kong Health Department is tracking down others who stayed in the hotel -- particularly the ninth floor -- at that time, she said. Hong Kong health officials have identified 203 patients with the illness. About a third of them involve family members and other close contacts of infected people, and the others involve health care personnel.
"We're not seeing any cases outside of these groups," Gerberding said.
Though the cause of the disease remains a mystery, "we can apparently prevent the spread of the illness by use of appropriate cautions in health care environments," she said.
Looking for a cause
CDC is working with other laboratories to find the cause of the disease. Labs in Germany and Hong Kong have found patients harboring particles of what appear to be paramyxoviruses -- responsible for such common illnesses as mumps and measles -- which they say may turn out to be the cause.
It also includes a subfamily of viruses that can be transmitted between animals and people.
In an attempt to prevent the disease from spreading elsewhere in the United States, health officers have begun meeting some 10,000 passengers on 50 flights per day arriving directly and indirectly from affected areas. So far, they have issued about 35,000 health alerts in four languages to warn arriving travelers to be alert to possible symptoms.
In more than five cases, sick passengers arriving on planes or boats have been intercepted. Typically, a mask is put on the person, who then is taken to a hospital and put in isolation, said Dr. Marty Cetron, deputy director of CDC's Division of Global Migration.
Other passengers, he said, are directed to contact their doctors if they become sick within seven days, the period in which symptoms typically appear.
The outbreak has led CDC to open its emergency operations center and move into a "full-court press in terms of the degree of support going into this operation," Gerberding said.
Though health authorities are still trying to determine who is at greatest risk, the fact that a number of healthy, middle-aged people were affected "tells us this is a disease that can be virulent and life-threatening even among those who would otherwise have been healthy," Gerberding said.
But the CDC director said she was encouraged at recent reports of people recovering from the disease. "Even in the absence of any specific therapy, [it means] that good supportive care can get people through the crisis and that they can recover."
The sudden appearance of the disease has led some people to speculate that it could be the work of terrorists. "All indications right now is that this is a naturally occurring infectious disease," Gerberding said. But, she added, "We're keeping an open mind about terrorism, especially given the time period that we're operating in."
So far, suspected cases have been reported in Canada, Germany, Italy, Ireland, Slovenia, Britain, Switzerland and Spain.
But the focus of the outbreak remains in Asia, where suspected cases have been reported in Hong Kong, Singapore, Thailand, Vietnam, Taiwan.
Officials suspect that the same disease surfaced last November in China's Guangdong province, killing five of 350 people affected before tapering off in mid-February.
CDC has issued a travel advisory suggesting that persons planning nonessential travel to Hong Kong, Guangdong, or Hanoi consider delaying their trips.
Symptoms can include rapid onset of fever above 100.4 degrees F, muscle aches, chills and sore throat, followed by shortness of breath, cough, and evidence of pneumonia on X-ray.
WHO reported Thursday that the antiviral drug ribavirin "may be responsible for some degree of clinical improvement" seen in critically ill patients in Hong Kong. "Intensive and good supportive care have also been associated with improved prospects of recovery," the agency said.