LAUSR

The Eurasian avian-like swine influenza A (H1N1) viruses (EAS-H1N1) have circulated in pigs since 1979, and human sporadically infected with EAS-H1N1 have been reported in several countries. In October 2016, the EAS-H1N1 infection in an adult hospitalized patient with severe pneumonia was identified in Fujian Province in China. The viral RNA was extracted form chicken embryo culture inoculated with throat swab, and complete genome sequences were obtained by RT-PCR and sequencing. Phylogenetic analysis showed that the virus was a novel triple-reassortant H1N1 virus containing genes from the Eurasian avian-like swine (HA, NA), A (H1N1) pdm09 (PB2, PB1, PA, NP, M) and classical swine (NS) lineages, termed influenza A/Fujian-cangshan/SWL624/2016 (FJ/624/16) virus. Complete sequences of FJ/624/16 virus were 94.3%-98.2% and 91.2%-95.4% identical in all 8 gene segments with A/Hunan/42443/2015 virus and A/swine/Guangdong/1/2010 virus respectively. In this study, the isolate contained E190D and D225E substitution within HA, suggesting the preference to α-2,6-linked sialosides and increase in the binding force of H1N1 virus in human upper respiratory tract. The virus was sensitive to neuramidinase inhibitors, but resistant to adamantanes. Several amino acid residues of FJ/624/16 virus might increase viral virulence or adaptation in mammals. In order to find the virulence and human-to-human transmission ability of viruses timely, further epidemiological and virological surveillance in swine and human ought to be enhanced as a part of an overall pandemic preparedness plan.