22 Mysterious Pneumonia Cases in U.S.
Officials "Cautiously Optimistic" About Test for SARS
"We are now closer to reality that this Paramyxoviridae virus has caused this," says David Heymann, MD, executive director of the communicable diseases section of the WHO. But he says this represents a whole range of different viruses, from some that cause measles and mumps to others that cause common respiratory infections and sometimes may not even cause symptoms.
"Just because we found it circulating in some people does not mean that it is not circulating in others. A whole series of studies has to be done to find out if this is the cause," says Heymann.
WHO officials say it is promising that many of the known forms of the Paramyxoviridae viruses have already been excluded, which suggests that this might be a new form of the virus.
Despite the difficulties in identifying the exact cause of SARS, investigators today announced a major step toward developing a test that could screen suspected SARS cases. Officials say that a laboratory has now succeeded in growing an infectious agent in the laboratory that appears to cause severe acute respiratory syndrome.
When researchers added blood from patients recovering with SARS to a cell culture, the growth of the virus was halted, but blood from healthy people had no effect on the virus. That indicates that persons with SARS had developed antibodies to the virus, which provides strong evidence that the virus is the likely cause of illness.
"This is not just some light at the end of the tunnel," said WHO virologist Dr Klaus Stöhr, who is coordinating the collaborative laboratory efforts. "This is a real ray of sunshine."
Gerberding says the virus appears to be particularly dangerous and potentially deadly to even healthy individuals, and early isolation and early care is critical to managing the pneumonia and respiratory illness caused by SARS.
But Gerberding added that there is promising news coming out of Vietnam, where some of the first SARS cases were reported. In Hanoi, there are more reports of people recovering from severe acute respiratory syndrome and being released from the hospital.