An Outbreak of Human Coronavirus OC43 Infection and Serological Cross-reactivity with SARS Coronavirus.
BACKGROUND
In summer 2003, a respiratory outbreak was investigated in British Columbia, during which nucleic acid tests and serology unexpectedly indicated reactivity for severe acute respiratory syndrome coronavirus (SARS-CoV).


METHODS
Cases at a care facility were epidemiologically characterized and sequentially investigated for conventional agents of respiratory infection, SARS-CoV and other human CoVs. Serological cross-reactivity between SARS-CoV and human CoV-OC43 (HCoV-OC43) was investigated by peptide spot assay.


RESULTS
Ninety-five of 142 residents (67%) and 53 of 160 staff members (33%) experienced symptoms of respiratory infection. Symptomatic residents experienced cough (66%), fever (21%) and pneumonia (12%). Eight residents died, six with pneumonia. No staff members developed pneumonia. Findings on reverse transcriptase-polymerase chain reaction assays for SARS-CoV at a national reference laboratory were suspected to represent false positives, but this was confounded by concurrent identification of antibody to N protein on serology. Subsequent testing by reverse transcriptase-polymerase chain reaction confirmed HCoV-OC43 infection. Convalescent serology ruled out SARS. Notably, sera demonstrated cross-reactivity against nucleocapsid peptide sequences common to HCoV-OC43 and SARS-CoV.


CONCLUSIONS
These findings underscore the virulence of human CoV-OC43 in elderly populations and confirm that cross-reactivity to antibody against nucleocapsid proteins from these viruses must be considered when interpreting serological tests for SARS-CoV.
Patrick
David M
DM
University of British Columbia Centre for Disease Control.
Petric
Martin
M
Skowronski
Danuta M
DM
Guasparini
Roland
R
Booth
Timothy F
TF
Krajden
Mel
M
McGeer
Patrick
P
Bastien
Nathalie
N
Gustafson
Larry
L
Dubord
Janet
J
Macdonald
Diane
D
David
Samara T
ST
Srour
Leila F
LF
Parker
Robert
R
Andonov
Anton
A
Isaac-Renton
Judith
J
Loewen
Nadine
N
McNabb
Gail
G
McNabb
Alan
A
Goh
Swee-Han
SH
Henwick
Scott
S
Astell
Caroline
C
Guo
Jian Ping
JP
Drebot
Michael
M
Tellier
Raymond
R
Plummer
Francis
F
Brunham
Robert C
RC