Surveillance for avian influenza virus in environments of farm produce markets in Zhuhai, 2017–2019

ObjectiveTo understand the distribution of avian influenza virus in environment of farm produce markets of Zhuhai, analyze the epidemiologic characteristics of avian influenza virus and provide evidence for the prevention and control of human infection with avian influenza.

MethodsSamples were collected from the environments of farm produce markets and poultry wholesale markets in Zhuhai during 2017–2019. The annual sampling started in November and finished in May. Fluorescence quantitative RT-PCR was used to detect the nucleic acid of influenza A virus, and the positive samples were further tested for the subtypes of H5, H7 and H9. The differences in the positive rate at different times, areas and places were analyzed with χ² test.

ResultsA total of 2072 samples were collected from the environments of the farm produce markets in Zhuhai during 2017–2019, and 916 positive samples of avian influenza A virus were detected (44.21%). The annual detection rate of avian influenza A virus showed an increase trend from November to February. The positive rate of samples in the non-restricted area was higher than that in the restricted area. The positive rate of bird stool samples was 55.10%, higher than others types of samples, and the detection rate of H9 subtype was highest (25.24%), followed by that of H5 subtype (2.46%) and H7 subtype (1.59%).

ConclusionThere was a high detection rate of avian influenza A virus H9 subtype in the environmental samples of the farm produce markets in Zhuhai. It is necessary to strengthen the environmental disinfection of poultry stalls in farm produce markets, and strictly implement all the prevention and control measures to protect people's health.