Surveillance for avian influenza virus in environments in Liaoning Province / 预防医学

ABSTRACT

Objective @#To learn the epidemic distribution of avian influenza virus in external environments in Liaoning Province,and to provide evidence for the prevention and control of avian influenza.@*Methods @#The environmental samples were collected monthly during 2016 and 2017（including samples from emergency monitoring in June to August,2016 and March to May,2017）from live poultry markets,live poultry wholesale markets,large-scale poultry farms（households）,free-range poultry famers and poultry processing factories in Liaoning Province. Real-time polymerase chain reaction assay was used to detect nucleic acid of Influenza A as well as H5,H7 and H9 subtypes in the environmental samples. The distribution of avian influenza virus in external environments in Liaoning Province was analyzed.@*Results @#A total of 4 037 environmental samples were collected and detected from 2016 to 2017,there were 177 copies of type A avian influenza virus and the positive rate of avian influenza A virus was 4.38%. The positive rate in 2017 was 6.26%, which was higher than 2.40% in 2016（P<0.05）. H9 subtype had the highest positive rate of 3.07%;H7 subtype was first detected in 2017. The positive rates of avian influenza virus from the first to fourth quarters of a year were 8.54%,4.88%,2.17% and 1.45%,respectively. The positive rates of avian influenza virus in live poultry markets were 8.08%,the highest among different sites,and the subtypes were mainly H9. The positive rates of avian influenza virus in samples of poultry cage and poultry washing sewage were 23.47% and 15.96%. H5 and H9 subtypes were detected in all types of samples,and H7 subtypes or mixed types were detected in samples of feces,poultry cage,poultry drinking water and chopping board.@*Conclusion @#The subtypes of avian influenza virus in the environments of Liaoning Province were mostly H9 and H5,and the H7 was first detected in 2017. Live poultry markets should be the key monitoring sites,especially in winter and spring.