Biomedical Engineering Reference
In-Depth Information
Table 1
Comparison of the Sequences of Two Strains of Severe Acute
Respiratory Syndrome (SARS)-Coronavirus Isolated From
Patients in Hong Kong at the Beginning of the Epidemic
a
Nucleotide position
CUHK-Su10
CUHK-W1
9404 T C
9479 T C
17564
b
T G
19064 A G
21721
b
G A
22222
b
T C
27827
b
T C
a
Sequence variations at seven positions between the two viral strains
(CUHK-Su10 and CUHK-W1) are indicated. The nucleotide positions are
numbered according to the sequence of GenBank accession number
AY274119.
b
Part of the haplotype suggested by The Chinese SARS molecular epide-
miology consortium for distinguishing the early, middle, and late phase of
the SARS epidemic in 2003.
in isolates CUHK-AG01, CUHK-AG02, CUHK-AG03 (GenBank accession
numbers AY345986, AY345987, AY345988) obtained from patients involved
in the Amoy Gardens outbreak in Hong Kong
(
11
)
. Later, these two genetic
fingerprints appeared in 10 completely sequenced Taiwanese isolates
(
16
)
.
Interestingly, toward the end of the epidemic, another type of fingerprint
was found by PCR-based method. A variant of the SARS-CoV with a 386-
nucleotide deletion was reported in a cluster of patients that seem to be epide-
miologically related
(
17
)
. Most of the cases were part of a documented outbreak
in the North District Hospital in Hong Kong.
We have illustrated that sequence variations among different isolates have a
remarkable epidemiological correlation. Thus, PCR amplification followed by
sequencing is a powerful tool in tracing the route of transmission. The sequence
information may provide objective support to epidemiological investigations.
Moreover, in the event that SARS re-emerges, one could quickly gain impor-
tant insight into the origin and evolution status of the SARS-CoV simply by
sequencing the critical sequence variations of the genome, as exemplified here.
However, to extract this wealth of information from the limited primary clini-
cal SARS specimens, we need very sensitive and efficient protocols to effi-
ciently amplify fragments of the SARS-CoV genome for analysis.
