河北省2005—2007年度流感流行特征分析

目的了解河北省流感流行特征、流感病毒优势株的变化，为流感防制提供科学依据。方法通过全国流感监测网络，收集2005—2007年度河北省流感或流感样病例（Influenza Like Illness，ILI）资料，对流行病学，病原学以及流感暴发疫情监测结果进行分析。采集ILI咽拭子标本用MDCK（Madin Darby Canine Kidney）细胞分离病毒，血凝抑制（Hemasslutination Inhibition，HI）试验鉴定病毒型别。结果2005-2007年两个流行期河北省ILI就诊百分比分别为4．50％和3．22％，按月统计ILI就诊百分比高峰出现在2005年12月和2007年1月；2005—2006年流行期采集ILI咽拭子标本938份，分离到流感病毒92株，分离率为9．81％。H1N1亚型57株占61．96％，H3N2亚型6株占6．52％，B型29株占31．52％。2005年11—12月为H1N1亚型；2006年1—2月为H1N1、H3N2亚型和B型同时流行，仍以H1N1亚型为主；进入3月后，H1N1亚型和B型同时流行，但B型已明显上升为优势株。2006—2007年流行期采集标本727份，分离到流感病毒88株，分离率为12．10％，H1N1亚型21株占23．86％，H3N2亚型66株占75．00％，B型1株占1．14％，H3N2亚型毒株为优势株。结论2005—2007年流行期河北省流感流行高峰为当年12月或次年1月。先后出现H1N1、H3N2和B型流感病毒的流行，流感病毒优势株发生了交替变换。

Analysis on Epidemic Characteristics of Influenza in Hebei Province During the Period of 2005 - 2007

Objective To understand the epidemic characteristics and the changes of the dominant strains of influenza, and to provide scientific basis for the prevention of influenza. Methods Data of outpatient visits for influenza- like illness （ILI） and outbreaks of influenza were collected through National Influenza Surveillance Network. The epidemiology and pathogen of ILI and outbreaks of influenza were analyzed. Samples were collected in the outpatients of ILI during the period of 2005 -2007. Influenza viruses were isolated by MDOK cell and subtypes were identified by HI test. Results During the period of 2005- 2007, the percentage of the number of ILI cases accounted for 4.50 % and 3.22 % of the total outpatient respectively in Hebei, there were two apparent peaks in December 2005 and January 2007. A total of 938 throat swab specimens were collected from 2005 to 2006, and 92 strains were identified for influenza viruses with an average isolation rate of 9.81%. Of the 92 strains, 57 （61.96%） were A subtype H1N1, 6 （6.52%） were A subtype H3N2 and 29 （31.52%） were B type. The circulating strain was A subtype H1N1 from November to December, 2005. A subtype H1N1 and H3N2 as well as B type viruses were coclrculating, but A subtype H1N1 was the dominant strain from January to February, 2006. A subtype H1N1 and B type all appeared, but the dominant position of H1N1 subtype was substituted by B type in March 2006. A total of 727 specimens were collected from 2006 to 2007, and 88 strains were identified for influenza viruses with an average isolation rate of 12.10%. Of the 88 strains, 21 （23.86%） were A subtype H1N1, 66 （75.00%） were A subtype H3N2 and 1 （1.14%） was B type. H3N2 virus was the predominant strain. Conclusion Two peaks of influenza in December and January were shown in Hebei from 2005 to 2007. Influenza A subtype H1N1 and H3N2 as well as B type viruses were co- circulating, and the influenza viruses had occurred switchover of dominant strain.