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SARS Epidemiology to Date
11 April 2003
- SARS
is a new disease which has its origins in Guangdong Province, China.
The earliest known cases were identified in mid-November 2002. Since
then, probable cases of SARS have been reported in 17 countries. .
- WHO
is constantly investigating and, where appropriate, verifying rumours
about SARS coming in from a wide range of sources.
- The
current cumulative number of cases of SARS is 2781 cases with 111
deaths, officially notified by ministries of health. The global case-fatality
rate for probable SARS is 4%.
- Most
SARS cases to date have occurred in young adults. This transmission
pattern largely reflects the age of health care workers, their family
members and social contacts, and international travellers. On the
basis of present data, children appear to be less likely to present
with SARS than adults.
- SARS
appears to be spread most commonly by close person-to-person contact
involving exposure to infectious droplets, and possibly by direct
contact with infected body fluids.
- China
continues to see new cases of SARS although the numbers are decreasing
following a peak in cases in February. To date, 1290 cases and 55
deaths have been reported from mainland China.
- Hong
Kong is experiencing the second largest outbreak of SARS with 998
cases and 30 deaths. A significant outbreak at the Amoy Gardens apartment
block between 27 March to 1 April resulted in a peak in cases. Stringent
public health measures appear to have controlled the Amoy Gardens
outbreak. However, cases continue to be reported in health care workers,
and Hong Kong health authorities are strengthening their infection
control and community-based public health measures accordingly.
- Canada
has experienced an outbreak of 97 probable SARS cases and 10 deaths.
Up to now, the outbreak has been largely confined to Toronto. All
cases have been epidemiologically linked to transmission related to
a health care setting and transmission among close contacts of known
SARS cases. In the Canadian outbreak, the higher case-fatality ratio
appears to be linked to the older age of the patients, who frequently
have underlying chronic disease.
- Infection
control and other public health measures implemented in Viet Nam have
effectively controlled the outbreak in Hanoi. Very low levels of transmission
have been reported after 24 March. Since the outbreak began on 26
February, 4 deaths have been reported.
- Although
Singapore continues to see new cases, including clusters in hospital
staff, inpatients, and visitors at two hospitals, the daily increase
in numbers has decreased since a peak in mid-March. As of 10 April,
a cumulative total of 126 cases with 9 deaths has been reported. Singapore
is currently investigating a new cluster at the Singapore General
Hospital affecting 52 persons in Wards 57 and 58, comprising 19 probable
and 33 suspect SARS cases. The index case was admitted to this hospital
on 24 March for the management of unrelated chronic illness, did not
show characteristic SARS symptoms initially, and therefore was not
placed in isolation and managed according to the principles of strict
infection control.
- Cases
continue to increase in the United States with 154 persons under investigation.
US figures include probable and suspect cases. The US now reports
limited transmission from patients to health care workers. No deaths
have so far been reported from the US.
- Areas
defined as "affected" are updated each day according to
the latest data on cases and evidence of patterns of transmission.
Epidemiological data indicate that SARS cases occurring in all other
countries became infected while present in one of the affected areas
or by direct contact with known cases of SARS.
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