Analysis of the HA Gene of the Novel Influenza A (H1N1) Virus in Taiwan and Epidemic Strains in Other Countries

Jih-Hui Lin

2009 Vol.25 NO.8

Correspondence Author： Jih-Hui Lin

Abstract：

The first outbreak of novel H1N1 influenza virus appeared in North America in April 2009. Until July 1, a total of 77,201 cases have been reported in 103 countries in the world with mortality rate of 0.43%. Through the genetic sequence analysis of influenza A (H1N1) virus, it was a double reassortants with European swine flu virus and North American swine flu virus, so it was called swine flu initially. Later it was renamed as novel influenza A (H1N1). Until July 1, there have been 70 confirmed cases in Taiwan, with 4.3% positive rate. We selected 6 positive specimens for cell culture and compared the HA gene from virus isolates, the result revealed 99% similarity, which was similar to the published results in the world currently. Through phylogenetic analysis, the gene sequence of influenza A (H1N1) virus isolates in Taiwan could be categorized as the same group with the virus in New York, USA and Mainland China, but different from other strains in the world. Since the clinical symptoms of novel influenza A (H1N1) were quite similar to classical seasonal flu, only laboratory tests could distinguish the difference. Thus, for a suspected case, one can rely on effective and accurate identification of the case to achieve the goal of rapid prevention. In order to ascertain whether or not the virus isolated in Taiwan has mutated or changed antigenicity, and whether or not that may affect pathogenicity and transmissibility, further analyses with control antigens and antiserum are needed.
Keywords: influenza A (H1N1), sequence analysis, Taiwan