Disease Outbreak Reported
22 March 2003
SARS virus isolated, new diagnostic test producing reliable
A team of scientists in the department of
microbiology, University of Hong Kong, has announced today success
in culturing the viral agent that causes Severe Acute Respiratory
Syndrome (SARS). Further progress in the development of a reliable
diagnostic test was simultaneously announced by the same team.
Using a special cell line, the Hong Kong scientists
isolated the virus from the lung tissue of a patient who developed
pneumonia following contact with a professor from Guangdong Province
in southern China. Both the professor and the contact have died.
Isolation of the virus now lays the solid foundation
for very rapid development of a diagnostic test.
The Hong Kong scientists have devised a basic test,
relying on the technique of neutralizing antibodies. In today’s
experiments designed to determine the accuracy of the test,
scientists found that it was able to detect tell-tale antibodies in
sera taken from eight SARS patients. The consistency of these
findings indicates that the test is reliably identifying cases of
This “hand-made” test will now be further developed
into a more sophisticated diagnostic test. A rapid and reliable
diagnostic test for SARS is urgently needed to assist the many
clinicians who need a tool for rapid confirmation of genuine cases.
Such a test can also help reassure the many “worried well” who are
flooding health facilities as international concern about this
disease and its rapid spread to new areas continues to increase.
Many common and usually self-healing illnesses mimic
the symptoms of SARS in its early stage.
With the virus now isolated, scientists in Hong Kong
and elsewhere can move forward quickly to characterize the agent,
determine its relationship with known viruses, and establish a
definitive identity. Results will be shared among 11 leading
laboratories in a network set up on Monday 17 March by WHO.
Exceptionally rapid progress
collaboration, with findings shared daily in teleconferences and by
email, has allowed advances that normally need months to take place
in a matter of days.
“This spectacular achievement is an example of what
the world can do when the intellectual resources of nations around
the world are focused on a single problem,” says Klaus Stöhr, a WHO
virologist who is coordinating the global laboratory network.
“Scientists who are by default academic competitors
are now working virtually shoulder to shoulder. In less than a week,
they have produced results which, in other circumstances, would
likely have taken months or more. This rapid advance is fuelling the
hope that SARS can and will be contained.” The virus responsible for
SARS is considered by some research groups to be a member of the
well-known Paramyxoviridae family. Yesterday, Canadian
researchers released findings suggesting that the
metapneumovirus, which belongs to this family, may be the
The metapneumovirus was first discovered by
Dutch scientists in June 2001 at a laboratory that is also included
in the new WHO network. At the time of its discovery, the virus was
known to cause respiratory disease in humans, including some cases
of pneumonia, but showed a different transmission pattern and was
much less severe than the SARS agent.
At this point, it cannot be ruled out that an entirely
different virus from another family may be responsible for the SARS
Identity of virus remains elusive
cautions that the race to identify the SARS causative agent is by no
means over. Although the virus has now been isolated, its identity
remains elusive. Other research groups in the network of
collaborating labs are producing hints that the causative agent may
belong to another virus family.
SARS is an emerging disease, first recognized in Asia
in mid-February, that has sickened over 380 persons on three
continents and caused severe pneumonia in a large proportion of
patients. A cumulative list of
affected countries and numbers of cases
and deaths is released each day on the WHO web site. Today’s
data indicate that slightly more than half of currently reported
cases have occurred in health care workers and medical students. The
remaining cases are in family members and other persons in close
contact with patients.
Investigative team travelling to China
WHO team of five experts is now en route to China to investigate the
possibility that an outbreak of a disease having similar symptoms
and affecting similar groups – health care workers and close
contacts of patients – may be linked to the current SARS
As of today, Hong Kong remains the most seriously
affected area. Authorities there have reported a total of 222 cases
in health care workers, medical students, and family members and
hospital visitors who have been in close contact with patients. Of
these, 217 have developed symptoms of pneumonia, and many are in