Investigation Of Infection Of Avian Influenza In Domestic Duck In Dongting Lake And Poyang Lake From 2014 To 2015

In order to understand the prevalence of avian influenza virus in domestic ducks in the Dongting and Poyang Lake region, we conducted active influenza virus surveillance in live poultry markets (LPM) and free-ranging duck on farms from winter 2014 until winter 2015. We sequenced the entire coding sequences of the genomes, analysis the evolutionary relationships and observed the genotypes of the isolates, analysis the difference between live poultry markets and farms, discussing the characteristic of AIVs in this region.In this study, specimens comprising 6,680 duck swab samples and 1,890 environmental samples were collected from 230 duck farms,2,170 duck swab samples and 170 environmental samples were collected from Live bird markets.329 AIVs(3.83%) and 473 AIVs(19.95%)were isolated, respectively. Form all specimens, H1, H3, H4, H5, H6, H7, H9, H10 and H11 was isolated, and H1 subtype can only isolated from LPM. We analysis the amino acid sequence of HA gene, all of the AIVs are not tend to binding human receptor, suggest they don't have the ability to infect mammals. In Phylogenetic tree, we find that various subtype of AIV show very complex spatiotemporal diversity and obvious heterologous. A majority of viruses form farms showed significant differences with viruses from live poultry markets, different lineages appear to diverge on a geographical. When the phylogenetic relationships among these isolates internal genes as well as the viruses genotypes were examined, we observed that extensive reassortment events had occurred, and some viruses from farms showed high homology with the strains isolated in wild birds in China's neighboring countries in the early years.Domestic duck farming in southern China occurs in high-density settings but in a free-range manner, There are no biosafety measures in place on these duck farms, Dongting Lake and Poyang Lake is on the East Asian-Australasian Flyway of migratory birds, many different species of wild aquatic birds migrate there every year for breeding, wintering, and summering, migratory birds and domestic ducks are in close contact, sharing water, food, and habitat, as a result, AIV of both sources coexist in duck farms, facilitating interspecies transmission and viral gene reassortment, the emergence of new avian influenza strains may occurred.All in all, our study emphasize that viruses at Dongting Lake and Poyang Lake show very complex spatiotemporal and geographical diversity, viruses from farms and live poultry markets exist different origin, various subtypes of AIVs appear complex reassortment. Our findings emphasize the importance of farmed domestic ducks in the Dongting and Poyang Lake region to the genesis and evolution of AIV and highlight the need for continued surveillance of domestic ducks in this region.