Abstract: Using micro plate method to isolate the influenza virus, Influenza B virus and its HA1 gene were identified by RT-PCR and Nested-PCR,The nucleotide sequence of HA1 gene were analyzed by Clustax, Mega6.0,Megalign. Results:47 influenza B positive samples were isolated from 1 002 fever samples collected from April, 2014 - to March, 2015. The highest isolation rate was found in August 2014, and January, 2015. The highest influenza B positive was found in 13~24 months old children,and the lowest positive rate was found in 0~6 months old children. There is no significant difference among children patients with influenza B virus infection in either-gender or departments source:87.23% of children of the Influenza B virus infection show the symptoms of fever and cough. HA1 fragment analysis indicates the isolated influenza B virus belongs to the Victoria strain, and shows a 86.1%~88.0% homology to the reference strain, B/Brisbane/60/2008 in nucleotide sequence. Three amino acids of the isolated strain were different from the reference strain. Conclusion:Influenza B virus isolated in Wuhan belongs to the Victoria strain, which has high homology with the international vaccine strain B/Brisbane/60/2008 and B/Texas/AF2741/2010 in the northern hemisphere and INFB representative strains in Hubei province. No new strain was found.

Key words: INFB, RT-PCR, nested PCR, HA1 gene