Shanxi Province From 2004 To 2005 Influenza Virus Pandemic Strain Genetic Variation And Antibody Study

Objective Influenza is acute respiratory infectious illnesses by influenza viruses.As a result of continuous antigenic changes, human antibodies produced from infection or vaccination with earlier strains may not be protective against viruses circulating in subsequent years.To study the regular pattern of type of local strains, to catch the variant and to direct the surveillance, diagnosis and prevention of influenza.The study on influenza and was carried out in shanxi during 2004~2005 epidemic seasons.Methods The influenza like individuals from medical department and paediatrics out patients of 3 hospitals in shanxi taiyuan were involved in this study during Oct.2004 through Mar 2005 and investigated basic information.Clinical specimens from patients with influenza within 3 days and without antiviral drug were inoculated in Madin-Darby Canine Kidney(MDCK)cells.Types of new isolates were identified by hemagglutinin inhibition (HI) .HA1 region of virus RNA were amplified by reverse transcription polymerase chain reaction (RT-PCR), then sequenced.The nucleotide sequences on HA1compared with 9 predominated strain of influenza virus in genebank.In March 2005,we collected 133,128and 132 persons'blood samples in the hospital of datong,jinzhong and linfen respectively, and detected the influenza virus antibody titer by HI test,excluding respiratory disease and having influenza vaccine patient.All data were analyzed by SPSS11.0 usingχ2-test,Kruskal-Wallis H test and so on.The sequence of HA1 region were analyzed by DNASTER and GENEDOC software.Results (1).During 2004~2005 epidemic season, the percent of influenza like patients in out patients were 0.23% ,peaked in February.(2). 13 strains of influenza viruses were isolated from 193 clinical specimens by MDCK cells during 2004~2005 epidemic season, peaked at January and February.(3).The HA1 domain of 13 epidemics trains HA gene were sequenced in the present study . 13 strains virus were all Yamagata like virus and belong to B/Shanghai/361/2002 lineages.The percent identity with B/Jiangsu/10/03 was the highest in 9 predominated strain of influenza virus in genebank. (4). With regard to B/Shanghai/361/2002 , 13 strains of influenza viruses have changed in antigen binding B,D and nearby sites. The number of glycosylation site have also been different from B/Shanghai/361/2002.(5). The positive rates and the geometric mean titers of B influenza virus (95.9%, 190.27) is the highest among the healthy population . The second is A3(91.6%,46.27) . The lowest is A1 (85.8%,35.58) .the distribution of three types antibodies in different districts and ages has significant difference.Conclusion (1).Influenza epidemic tendency of shanxi in 2004~2005 was the same to the other provinces in China.influenza B had becomed predomined strain.(2).With regard to B/Shanghai/361/2002, the gene of 13 strains virus had varied.(3).After 2004～2005 , population...