WASHINGTON, March 21 (UPI) -- Centers for Disease Control and Prevention officials said Friday they increased the number of suspected cases of the mysterious severe acute respiratory syndrome outbreak they are investigating to 22.
Officials said the agency also is investigating two cases in which Americans who contracted the pneumonia-like illness while traveling abroad might have transmitted it to others when they returned to the United States, CDC Director Dr. Julie Gerberding said during a teleconference.
There have been no U.S. deaths so far from SARS, but there are suspected cases of infection in 12 states. Worldwide, more than 350 cases of the illness, including 10 deaths, have been reported in 14 countries.
Referring to the two overseas travelers, Gerberding said, "We have identified a situation where a case in a traveler may have involved transmission to others in the United States"
In one case, an individual who traveled to Asia might have infected two healthcare workers who provided care. In another case, a person who also traveled to Asia is thought to have transmitted the infection to a family member.
The CDC is investigating the cases of two Americans who stayed in the Hong Kong Metropole Hotel, which might have been where the outbreak began, Gerberding said. The two individuals are included among the 22 cases, she noted.
Also on Friday, World Health Organization officials said they might have isolated the infectious agent responsible for SARS.
WHO spokesman Dick Thompson told United Press International, "We may have grown, but are not sure, the infectious agent that causes the disease."
Researchers "have grown in cell cultures an infectious agent but we don't know exactly what it is," Thompson said. The agent may be a new member of the paramyxoviridae family of viruses, which includes diseases such as mumps and measles, he said. However, it also could be something different that merely resembles a paramyxo virus, he noted.
Further experiments seemed to confirm the researchers had isolated the culprit virus for the SARS outbreak. Researchers exposed the agent to blood from recovering patients and found the agent died, indicating the patients had developed protective antibodies against the virus. Blood from healthy people did not kill the agent.
WHO officials are still conducting additional tests to conclusively identify the virus, Thompson said.
"This is just another step down the road but it's a good step," he said. "It may mean we could soon develop a diagnostic test and that would be a huge step forward."
Gerberding said CDC researchers are "working around the clock" to identify cause of the illness. The agency also is working with other labs around the world and consulting molecular microbiologists who have expertise in identifying novel organisms, she said.
In the meantime, appropriate safeguards can prevent the illness from infecting others, she said.
"We know that we can apparently prevent spread of this illness by use of appropriate precautions in the healthcare environment," such as isolating the patient and the use of masks by doctors and nurses, she said. "So far we are not seeing any cases even in Asia outside of" healthcare workers and close family contacts of the infected patients, she added.
CDC officials also "have taken several steps in the last few days even in the last 24 hours to assist in our progress of the investigation and interventions to prevent spread," Gerberding said.
This includes distributing "35,000 health alerts to arriving travelers and (intercepting) five planes and boats that have passengers ill that have traveled to the affected areas," she said.
Authorities also are still trying to determine which treatments are most effective against the agent. "It's a confused picture still but we are trying to straighten out," Thompson said.
The majority of the suspected cases have occurred in Hong Kong, Vietnam and Singapore. Hong Kong is investigating 203 cases, including 6 deaths; Vietnam 62 cases and 2 deaths, and Singapore 39 cases, no deaths.
U.S. cases have been reported in California with 6; Hawaii with 3; one each for Maine, Massachusetts, New Jersey, New Mexico, Rhode Island, Utah and Wisconsin, and two each for North Carolina, New York and Virginia.
