Identification of severe acute respiratory syndrome in Canada.
BACKGROUND
Severe acute respiratory syndrome (SARS) is a condition of unknown cause that has recently been recognized in patients in Asia, North America, and Europe. This report summarizes the initial epidemiologic findings, clinical description, and diagnostic findings that followed the identification of SARS in Canada.


METHODS
SARS was first identified in Canada in early March 2003. We collected epidemiologic, clinical, and diagnostic data from each of the first 10 cases prospectively as they were identified. Specimens from all cases were sent to local, provincial, national, and international laboratories for studies to identify an etiologic agent.


RESULTS
The patients ranged from 24 to 78 years old; 60 percent were men. Transmission occurred only after close contact. The most common presenting symptoms were fever (in 100 percent of cases) and malaise (in 70 percent), followed by nonproductive cough (in 100 percent) and dyspnea (in 80 percent) associated with infiltrates on chest radiography (in 100 percent). Lymphopenia (in 89 percent of those for whom data were available), elevated lactate dehydrogenase levels (in 80 percent), elevated aspartate aminotransferase levels (in 78 percent), and elevated creatinine kinase levels (in 56 percent) were common. Empirical therapy most commonly included antibiotics, oseltamivir, and intravenous ribavirin. Mechanical ventilation was required in five patients. Three patients died, and five have had clinical improvement. The results of laboratory investigations were negative or not clinically significant except for the amplification of human metapneumovirus from respiratory specimens from five of nine patients and the isolation and amplification of a novel coronavirus from five of nine patients. In four cases both pathogens were isolated.


CONCLUSIONS
SARS is a condition associated with substantial morbidity and mortality. It appears to be of viral origin, with patterns suggesting droplet or contact transmission. The role of human metapneumovirus, a novel coronavirus, or both requires further investigation.
Poutanen
Susan M
SM
Toronto Medical Laboratories and Mount Sinai Hospital Department of Microbiology, Toronto, Canada.
Low
Donald E
DE
Henry
Bonnie
B
Finkelstein
Sandy
S
Rose
David
D
Green
Karen
K
Tellier
Raymond
R
Draker
Ryan
R
Adachi
Dena
D
Ayers
Melissa
M
Chan
Adrienne K
AK
Skowronski
Danuta M
DM
Salit
Irving
I
Simor
Andrew E
AE
Slutsky
Arthur S
AS
Doyle
Patrick W
PW
Krajden
Mel
M
Petric
Martin
M
Brunham
Robert C
RC
McGeer
Allison J
AJ
D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D002910:Chronology as Topic; D016358:Contact Tracing; D003371:Cough / Q000209:etiology; D004196:Disease Outbreaks; D018450:Disease Progression; D004417:Dyspnea / Q000209:etiology; D005192:Family Health; D005260:Female; D005334:Fever / Q000209:etiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011859:Radiography; D045169:Severe Acute Respiratory Syndrome / Q000150:complications / Q000453:epidemiology* / Q000635:transmission