Geographic patterns of genetic mutations, local persistence, and global circulation of influenza A/H1N1pdm09 virus during the pandemic and post-pandemic periods

Keywords: Influenza A, Pandemic, H1N1, Phylogeography, Phylodynamics, Medical Geography, Infectious disease
Abstract Type: Paper Abstract

Abstract

Local persistence of influenza A in tropical and subtropical regions in Asia is one of the factors driving the emergence of antigenic variants of the virus. Such variants are less detectable to the human immune system, thereby allowing for influenza A to go on to circulate among human populations and causing periodic influenza epidemics in winter in temperate regions. To understand the patterns of the evolutionary dynamics of the A/H1N1pdm09 virus from April 2009 to June 2011, we investigated the geographic distribution of genetic mutations, local persistence, and the global patterns of viral transmission using a phylogeographic approach. After the emergence of the A/H1N1pdm09 virus in North America, the viruses were introduced into Asian countries via East Asia, and then migrated to South Asia and the Malay Peninsula. We identified local persistence of the A/H1N1pdm09 viruses mainly in South Asia, which might promote the proliferation of viruses carrying amino acid substitutions as a result of human-virus interaction. Meanwhile, the viruses did not locally persist in China over the summer and the influence on the global circulation of the A/H1N1pdm09 virus was not significant. Better understanding of the geographic patterns of the evolution and spread of pandemic viruses will provide insight into the evolutionary dynamics of infectious viruses, which will help us prevent and predict the next pandemics.