Laboratory-based surveillance and molecular epidemiology of influenza virus in Taiwan.
A laboratory-based surveillance network of 11 clinical virological laboratories for influenza viruses was established in Taiwan under the coordination of the Center for Disease Control and Prevention (CDC), Taiwan. From October 2000 to March 2004, 3,244 influenza viruses were isolated, including 1,969 influenza A and 1,275 influenza B viruses. The influenza infections usually occurred frequently in winter in the northern hemisphere. However, the influenza seasonality in Taiwan was not clear during the four seasons under investigation. For example, the influenza A viruses peaked during the winters of 2001, 2002, and 2003. However, some isolated peaks were also found in the summer and fall (June to November) of 2001 and 2002. An unusual peak of influenza B also occurred in the summer of 2002 (June to August). Phylogenetic analysis shows that influenza A isolates from the same year were often grouped together. However, influenza B isolates from the year 2002 clustered into different groups, and the data indicate that both B/Victoria/2/87-like and B/Yamagata/16/88-like lineages of influenza B viruses were cocirculating. Sequence comparison of epidemic strains versus vaccine strains shows that many vaccine-like Taiwanese strains were circulating at least 2 years before the vaccine strains were introduced. No clear seasonality of influenza reports in Taiwan occurred in contrast to other more continental regions.
Shih
Shin-Ru
SR
Chang Gung Memorial Hospital & Chang Gung University, Taipei, Taiwan.
Chen
Guang-Wu
GW
Yang
Ching-Chun
CC
Yang
Weng-Zhi
WZ
Liu
Ding-Ping
DP
Lin
Jih-Hui
JH
Chiu
Shu-Chun
SC
Chen
Haur-Young
HY
Tsao
Kuo-Chien
KC
Huang
Chung-Guei
CG
Huang
Ya-Ling
YL
Mok
Chee-Keng
CK
Chen
Chi-Jene
CJ
Lin
Tzou-Yien
TY
Wang
Jen-Ren
JR
Kao
Chuan-Liang
CL
Lin
Kwei-Hsian
KH
Chen
Li-Kuang
LK
Eng
Hock-Liew
HL
Liu
Yung-Ching
YC
Chen
Po-Yen
PY
Lin
Jen-Shiou
JS
Wang
Jen-Hsien
JH
Lin
Cheng-Wen
CW
Chan
Yu-Jiun
YJ
Lu
Jang-Jih
JJ
Hsiung
Chao A
CA
Chen
Pei-Jer
PJ
Su
Ih-Jen
IJ
D000818:Animals; D004285:Dogs; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D009981:Influenza B virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D007753:Laboratories; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D018571:Sentinel Surveillance; D017422:Sequence Analysis, DNA; D013624:Taiwan / Q000453:epidemiology; D014773:Virology