Analysis of haemagglutinin gene of the first influenza A-H1N1 viral strain isolated in Guangdong Province during an influenza A pandemic in 2009 / 中华传染病杂志

ABSTRACT

Objective To detect and analyze the haemagglutinin (HA) gene of the first influenza A-H1N1 viral strain isolated in Guangdong Province during an influenza A pandemic in 2009.Methods A-H1N1 virus strain was isolated from the throat swab of the first patient diagnosed with A-H1N1 virus infection in Guangdong Province in 2009. Viral nucleonic acid was extracted from supernatant of cell culture and amplified using reverse transcriptase-polymerase chain reaction (RT-PCR) with HA gene-specific primers. The product was cloned, sequenced, and the homology was analyzed. Results A 1710 bp HA gene of the first influenza A-H1N1 viral strain in Guangdong Province in 2009 was acquired, which was named as A/GuangzhouSB/01/2009 (H1N1) HA with GenBank access No. GQ268003. The homology of the studied HA gene and the 277 influenza A (H1N1) isolates reported in the epidemic areas was 99.0%-99.8%, and as high as 99.8% when compared with the isolates reported in the United States where the patient had traveled. When the studied HA gene was compared with 25 isolates of Chinese seasonal A-H1N1 virus, the homology was 72.3%-85.6%. Conclusions The homology of the first isolated A-H1N1 viral strain in Guangdong Province in 2009 and epidemic influenza A-H1N1 virus is high, while it is low compared with Chinese seasonal A-H1N1 virus.