Changing geographic patterns and risk factors for avian influenza A(H7N9) infection in China

150 words) 32 The 5 epidemic wave in 2016-2017 of avian influenza A(H7N9) virus in China caused more 33 human cases than any previous waves but the factors that may explain the recent range expansion 34 and surge in incidence remain unknown. We investigated the effect of anthropogenic, poultry and 35 wetland information and of market closures on all epidemic waves (1-5). Poultry predictor 36 variables recently became much more important than before, supporting the assumption of much 37 wider H7N9 transmission in the chicken reservoir, that could be linked to increases in 38 pathogenicity. We show that the future range expansion of H7N9 to northern China may translate 39 into a higher risk of coinciding peaks with those of seasonal influenza, leading to a higher risk of 40 reassortments. Live-poultry market closures are showed to be effective in reducing the local 41 incidence rates of H7N9 human cases, but should be paired with other prevention and control 42 measures to prevent transmission. 43 not peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/146183 doi: bioRxiv preprint first posted online Jun. 8, 2017;