Analysis On Monitoirng Situation Of Influenza In Changchun From2006to2011

The influenza is the first worldwide Surveillance disease.Changchun as one of theSurveillance influenza cooperation project city, now has a National Influenza SurveillanceNetwork Laboratory (Changchun Municipal Center for Disease Control and prevention ofvirus laboratory) and two national influenza surveillance sentinel hospitals (ChangchunChildren’s Hospital and Central Hospital of Changchun). The influenza-like illnesses arerapidly increased at all levels of medical institutions from each October to the following Marchin Changchun City. In order to control and prevent influenza epidemic in Changchun city,develop targeted anti-epidemic strategy to provide a scientific basis, protect people’s health andpromote social and economic development, the influenza surveillance carried out in the winterand spring has important significance.Objectives: To analyze the epidemic characteristics of influenza of Changchunfrom2006to2011, and to understand the epidemic distribution characteristics ofinfluenza and the variability of the predominant strains of influenza virus inChangchun from2006to2011.Methods：The epidemiology surveillance data and the virology surveillance datawere collected from China influenza surveillance information system in ChinaInformation System for Disease Control and Prevention in Changchun city from2006to2011. Excel2003was used to descript statistics and statistical software SPSS16.0for statistical analysis and probes into the epidemic distribution characteristicsof influenza and the variability of the predominant strains of influenza virusin Changchun from2006to2011.Results:1.17,878cases of influenza-like illness were reported by two influenzasurveillance sentinel hospitals in Changchun City from2006to2011, while the totalnumber of outpatient and emergency clinic is1758295. Influenza-like cases accountedfor1.02%. The percentage of cases of influenza-like accounted for emergencytreatment was decreased by year in Changchun City, but the percentage rose in2009. 2. The high incidence of influenza was in December and January of each year inChangchun. In2010and2011, the high incidence of influenza was later than theseyears before.3. The component ratio of influenza-like illness in children under the age of15inChangchun city from2006to2011was higher, but more than60years old lowest.Different gender on the influenza is susceptible degree. The Men and women sex ratiovariation range was1.49~0.91. Every year influenza-like cases men were more thanwomen except2010. The component ratio of influenza-like illness was the highest inChaoyang District of Changchun city while the highest in Nanguan District in2011.4. Among6annual influenza surveillance,1416throat swab specimens withinfluenza-like illness were detected from2006to2011,228influenza viruses wereidentified by separation cell, and the positive rate was16.10%. The positive rate ishigher in2007and2011, respectively32.22%and30.68%. The positive rate is lowerin2006and2009, respectively7.83%and3.61%.228influenza virus consist of82A(H3) types,46BV types,50A(H1) types,33A(new H1) types and17BY types, thepercentage respectively37%,20%,22%,14%and7%.Conclusions：1. The percentage of cases of influenza-like accounted for emergency treatment isdecreased each year, but increased in2009.2.Winter and spring are high incidence of flu seasons of Changchun City.3. The constituent ratio of influenza-like illness in children under the age of15.Different gender on the influenza susceptible degree is different.4. The detected influenza virus subtypes were significantly different in each year. Theepidemic dominant virus were A (H3) subtype and A (H1) subtype in2006; the A (H3) subtypeand the BV subtype in2007; the A (H1) subtype in2008and2009; the A (H1) subtype, A (H3)subtype and BV subtype in2010; the A(new H1) type in2011. Each subtype of influenza virusbetween different gender and different age groups showed no significant difference.