Abstract
From 2016 to 2018, surveillance of influenza A viruses in wild birds was conducted in Shanghai, located at the East Asian–Australian flyway, China. A total of 5112 samples from 51 species of wild birds were collected from three different wetlands. The total three-year prevalence of influenza A viruses among them was 8.8%, as assessed using real-time polymerase chain reaction (PCR) methods, and the total prevalence was higher in Anseriformes (26.3%) than in the Charadriiformes (2.3%) and the other orders (2.4%) in the Chongmin wetlands. Anseriformes should be the key monitoring group in future surveillance efforts. The peak prevalence of influenza A viruses in Charadriiformes were in April and September, and in other bird orders, the peaks were in November and December. Twelve subtypes of haemagglutinin (HA; H1–H12) and eight subtypes of neuraminidase (NA; N1, N2, N4–N9) were identified in 21 different combinations. The greatest subtype diversity could be found in common teal, suggesting that this species of the bird might play an important role in the ecology and epidemiology of influenza A viruses in Shanghai. These results will increase our understanding of the ecology and epidemiology of influenza A viruses in wild bird hosts in eastern China, and provide references for subsequent surveillance of influenza A virus in wild birds in this area.
Highlights
Wild birds are generally recognized as the natural reservoir of avian influenza A viruses (AIVs), and most hemagglutinin (HA) and neuraminidase (NA) subtypes have been detected in them [1].AIVs usually replicate in the epithelial cells of the intestinal tract of wild birds and are excreted in high concentrations in their feces into the water [2]
All experiments were conducted under biosafety level (BSL)-2 conditions
The total prevalence in this study was apparently higher than previous reports in South-eastern China and Central China located on the East Asian–Australasian flyway, which were about 0.65–8% [15,16,17]
Summary
Wild birds are generally recognized as the natural reservoir of avian influenza A viruses (AIVs), and most hemagglutinin (HA) and neuraminidase (NA) subtypes have been detected in them [1]. Investigation of influenza virus circulation among wild birds on their flyways might help us to understand the mechanisms of the spread of AIVs and provide early warning influenza outbreaks in domestic poultry. According to a survey report, a total of 436 bird species, belonging to 20 orders and 58 families, have been recorded in Shanghai since the early 20th century [6]. Viruses 2020, 12, 1031 to 20 orders and 58 families, have been recorded in Shanghai since the early 20th century [6]. AIVsgap from birds waswe further further strengthened in this region To addressof this in wild knowledge, reportstrengthened the results in of this region.
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