Screening Test for SARS Nears Reality
Evidence on Likely Cause of Mysterious Respiratory Illness Mounting
March 27, 2003 -- Scientists in Hong Kong say they have finally developed a basic test to diagnose the mysterious illness known as SARS (severe acute respiratory syndrome). Meanwhile, officials across Southeast Asia have enacted sweeping new measures to curb the spread of the deadly respiratory disease.
The World Health Organization says the Hong Kong diagnostic test is based on polymerase chain reaction (PCR) technology that identifies the molecular makeup of the virus thought to cause SARS. Initial studies of the test consistently confirmed known SARS cases early in their infection and produced negative results in healthy people.
Additional studies to validate the test using genetic information are currently under way, and the WHO is making these test materials available immediately to other labs throughout the world for further evaluation.
Coronavirus Considered Likely cause of SARS
Evidence is also mounting that a previously unknown virus in the coronavirus family is responsible for SARS.
"Data from many network laboratories indicate that a coronavirus is the primary cause of the disease," says WHO virologist and epidemiologist Klaus Stöhr, in a news release. "This virus is unlike any known human or animal member of this virus family. It is consistently found in specimens from SARS patients from many countries. It has been isolated in cell-culture. We are very close to knowing for sure."
But CDC officials say it's still too early to be definitive about the cause of the mysterious respiratory disease that has now affected an estimated 1,408 worldwide, including 53 deaths.
"It doesn't do anyone any good to jump to conclusions," says James Hughes, MD, director of the National Center for Infectious Diseases at the CDC at a briefing today. "The possibility of co-infection [with another virus] in at least some patients has to be kept in mind."
The CDC today also raised the number of suspected SARS cases in the U.S. to 51 across 21 states. Officials say 44 of those cases are among people who have recently traveled to affected areas in Southeast Asia, five are people who had close, household contact with those travelers, and two are healthcare workers who cared for an infected individual.
So far, no deaths have been reported in this country due to severe acute respiratory syndrome. Hughes says the suspected SARS cases in the U.S. seem to be milder than those seen abroad. Only 14 cases have gone on to develop pneumonia, and one has required mechanical assistance with a ventilator to breathe. He credits this to early recognition of the condition and good medical management of the affected individuals.