Analysis on Influenza Pathogenic Monitoring in Hunan Province in 2006

Objective To understand the epidemic situation and the distribution of influenza virus types,and to analyze the epidemic trend for the disease control.Methods Throat swabs were collected from patients with influenza-like illnesses(ILI).Influenza viruses were isolated by Madin-Darby Canine Kidney(MDCK)cell and identified by hemagglutination inhibition(HI)test.The strains were then confirmed in the National Influenza Center(NIC).Results A total of 3,499 throat swab specimens were collected from 12 sentinel hospitals in Hunan in 2006,of which 258 strains were positive for influenza virus.The positive rate of isolation was 7.37 %.After identifying by NIC,202 strains were influenza A-H1N1,11 influenza A-H3N2,43 influenza B virus,and 2 strains turned to negative.Altogether 179 throat swab specimens were collected in the influenza outbreaks in 2006,of which 75 strains were positive for influenza virus.The positive rate of isolation was 41.90%.Of the 75 strains,12 strains were influenza A-H1N1,62 influenza B virus,and 1 strain turned to negative after identifying by NIC.Conclusions There are influenza activities throughout 2006 in Hunan Province.Type A(H1N1),A(H3N2)and B of influenza viruses could be isolated.A-H1N1 subtype is the dominant strain,while type B is the main influenza virus in the influenza outbreaks.