Disease Outbreak Reported
20 March
2003
Investigation of causative agent gains momentum
Highly specialized testing of specimens from patients ill with
Severe Acute Respiratory Syndrome (SARS) continues at top speed in
top labs, expedited by electronic sharing of results. WHO is
increasingly optimistic that conclusive identification of the
causative agent can be announced soon. The development of a precise
diagnostic test could follow quickly.
Collaboration in the
race to find the causative agent is taking place within the
framework of a network of labs set up on Monday.
Research is
now focused on the Paramyxoviridae family of viruses. This family
includes several well-known viruses, such as those causing mumps,
measles and common respiratory ailments. It also includes a
subfamily of viruses capable of infecting multiple animal species,
including humans. This subfamily was implicated in the emergence
during the 1990s of new and severe diseases in humans caused by
Hendra and Nipah viruses. The virus jumped directly from animal
hosts (horses and pigs) to humans. No person-to-person transmission
was documented in outbreaks caused by either virus.
New
treatment network WHO has today established a cooperative
network of clinicians for SARS diagnosis and treatment. The network
brings together, via two daily teleconferences, clinicians in the
most heavily affected Asian countries and in Europe and North
America. Clinicians participate on the basis of either first-hand
experience in the management of SARS cases or leading expertise in
the diagnosis and management of unusual infectious
diseases.
Participants are pooling data on cases and sharing
X-ray pictures. Chest X-rays are, at present, one of the main tools
for distinguishing between suspected and probable cases. Treatment
guidelines, including criteria for safe discharge of patients from
hospitals, are also being established on the basis of shared
experiences.
Pending definitive identification of the
causative agent, a combination of treatments are being tried to cure
cases. WHO is providing support, in the form of protective equipment
and supplies, to help the most heavily affected hospitals prevent
further spread within hospital settings, where the overwhelming
majority of new infections have occurred.
If a paramyxovirus
is confirmed to be the cause, WHO will be in a much better position
to recommend a treatment.
The antiviral drug, ribavirin, may
be responsible for some degree of clinical improvement observed in
critically ill patients in Hong Kong Special Administrative Region
of China. Intensive and good supportive care have also been
associated with improved prospects of recovery.
Update on
cases and affected countries As of 20 March, 306 suspected
and probable cases, including 10 deaths, have been reported from
eleven countries. These figures represent an additional 42 cases and
one death compared with the previous day. Increases were reported in
Canada (1), Hong Kong (23), Singapore (3), Taiwan, China (1), the
United Kingdom (1), and Viet Nam (6). Switzerland, reporting 7
suspected cases, was added to the list.
Possible cases in
airline passengers and crew member ruled out Press reports
have referred to 2 suspected cases of SARS, one in an airline crew
member and a second in a passenger, travelling on separate flights
from Hong Kong and Taipei to Viet Nam.
Both suspected cases
have been investigated and are now ruled out as cases of SARS.
Index case in Hong Kong outbreak WHO has welcomed
a report from the Hong Kong Department of Health, released
yesterday, that may have identified the “index” case in the outbreak
in the Prince of Wales Hospital in Hong Kong. In an outstanding
example of detective work, epidemiologists have determined that 7
people who contracted SARS recently stayed in or visited the
Metropole hotel in Kowloon last month. The 7 persons investigated
include 3 visitors from Singapore, 2 from Canada, one China Mainland
visitor, and a local Hong Kong resident.
The investigation
revealed that all 7 stayed in or visited the same floor of the hotel
between 12 February and 2 March. The local Hong Kong resident is
believed to be the index case, who subsequently infected other early
cases in the outbreak. He had visited an acquaintance staying at the
hotel from 15 to 23 February. The visitor from Mainland China, who
became sick a week before staying at the hotel, is considered the
original source of the infection. No further cases have been linked
to the hotel.
Absolute need for continued vigilance
WHO is underscoring the need for continued vigilance. Experience
with other emerging diseases makes it clear that, should the
causative agent turn out to be a virus, the new disease could
establish endemicity, especially in light of abundantly documented
human-to-human transmission. The world must protect itself against
the widespread establishment of another new infectious
disease.
WHO concern is now increasingly focused on
preparation to assist vulnerable countries in the likely event that
cases continue to spread. Up to now, all imported cases have
occurred in countries well-equipped and well-prepared to institute
WHO-recommended precautions, including isolation and barrier nursing
practices, for preventing spread to others, whether health care
workers or family members. In view of the rapid spread of this
disease to new countries via exposed air travellers, any country
with an international airport is potentially at risk.
This
focus on preparedness underscores the need for a concerted effort to
defend global public health security. In an era of close
interconnectedness and rapid air travel, an outbreak anywhere in the
world is a potential threat to health everywhere.
International collaboration – on the part of the medical and
research communities, multinational teams in the field, and health
authorities around the world – in the reporting, investigation, and
management of this outbreak has been outstanding.
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