Detection of H5 and H9 subtype avian influenza viruses isolated at various sites in Shiyan city, 2012

Objective To explore the distribution of H5 and H9 subtype avian influenza viruses in Shiyan city of Hubei province and to provide evidence for prevention and control of avian influenza.Methods Totally 302 samples were collected from five different typical sites with poultry exposure quarterly in Shiyan in 2012,and then the samples were detected with real-time PCR methods.The data were analyzed with SPSS 17.0.Results The detection rate of influenza A virus (Flu A)was 26.82%(81/302)for the 5 sites,with the detection rate of 5.96% (18/302)for H5 subtype and 17.88% (54/302)for H9 subtype.There was a significant difference in the distribution of H5 and H9 subtype (χ²=6.0,P=0.014).The positive rate of Flu A of the samples was 64.91% (37)for rural live poultry markets,58.58%(43)for poultry slaughtering and processing factories,1.69%(1)for wild migratory bird habitats,respectively,and there were no Flu A positive samples detected for household free-range poultry farms and large poultry farms.The detection rates of H5 subtype were lower than that of H9 subtype obviously for rural live poultry markets and large poultry slaughtering factories(χ²=7.784,P﹤0.05;χ²=21.564,P﹤0.05).The detection rates of Flu A,H5,H9 were affected by the type of the sample and seasonal time of the sampling.Conclusion H9 subtype is a dominant avian influenza virus strain in the five sites with poultry exposure in Shiyan city,and urban and rural live poultry markets and poultry slaughtering and processing factories are key sites to be monitored for the control of avian influenza.