上海地区2004年至2008年甲型流行性感冒病毒亚型的分布

Analysis of the distribution of subtype of influenza A of 2004-2008 in Shanghai area

目的分析近5年上海地区甲型流行性感冒（流感）病毒亚型的分布并探究其原因。方法对上海地区流感监测哨点流感样患者和聚集性流感暴发患者，采集咽拭子标本接种犬肾细胞（MDCK），直接荧光免疫法鉴定阳性分离株型别，多重RT—PCR鉴定亚型。结果2004年至2005年初的季节性流感以A／H3N2为主；2005年末至2006年中期的季节性流感以A／H1N1为主；2006年末到2007年10月份分离到的流感毒株基本为A／H3N2亚型；2008年1月至5月份，人群流感病毒分离株仍以A／H3N2处于优势地位，但从2008年7月开始的季节性流感则以A／H1N1占绝对优势。结论近5年上海地区季节性流感主要为甲型流感病毒H3N2和H1N1亚型，但在不同年份的季节性流感中流行强度有所不同。

Objective To analysis the distribution of subtype of influenza A of 2004-2008 in Shanghai area and to explore the reason. Methods Throat swabs were collected from patients with influenza-like illness in the sentinel surveillance clinic in Shanghai from 2004 to 2008, and inoculated in Madin-Darby canine kidney （MDCK） cells. Influenza viruses were identified and typed by direct immunofluorescence assay （DIF） and sub-typed by multiplex reverse transcriptase-polymerase chain reaction （mRT-PCR）. Results During seasonal epidemic of influenza from 2004 to 2008, influenza A/H3N2 viruses dominated from 2004 to the beginning of 2005, and then were subrogated by A/H1N1 from the end of 2005 to middle 2006. Subsequently, influenza A/H3N2 again contributed to most influenza events from the end of 2006 to Oct. 2007 and kept predominating from Jan to May in 2008 while A/H1N1 became dominating since Jul, 2008. Conclusion Though A/H3N2 and A/H1N1 were main seasonal influenza A subtypes in recent 5 years in Shanghai, the dominated subtype varied in different season.