Surveillance results of avian influenza virus in external environment in Quzhou, Zhejiang, 2013–2018

ObjectiveTo understand the distribution of avian influenza virus in the external environment in Quzhou, Zhejiang province, from 2013 to 2018, and provide scientific evidence for the prevention and control of human infection with avian influenza virus.

MethodsThe external environmental samples were collected from different surveillance sites of Quzhou for the nucleic acid detection of avian influenza viruses by using real-time RT-PCR during 2013–2018, and the results were used for statistical analysis.

ResultsA total of 5 290 environmental samples were collected from 2013 to 2018, in which 1 809 were positive for avian influenza A virus (34.20%), The subtype identification showed that H9 and unspecific type were main subtypes, the positive rate were 44.50% and 29.13% respectively. The positive rate was highest in Kaihua county (54.85%) and lowest in Longyou county (17.25%). The detection rate in live poultry markets was highest (45.94%) in 5 types of places, and the detection rate in surface swabs of chopping boards for slaughtering or placing poultry products was highest (58.96%) in 6 types of samples. The positive rates were significantly higher during January-March (38.06%) and during October-December (37.23%). There were significant differences in time, area, place and sample type specific distributions of avian influenza viruses (all P＜0.001).

ConclusionThere were different subtypes and mixed types of avian influenza virus contamination in the environment in Quzhou. It is important to strengthen the surveillance for avian influenza virus in environment and take comprehensive prevention and control measures to reduce the risk of human infection with avian influenza virus.