Researchers Retrace Key Mutations in Reassorted H1N1 Swine Flu Virus With Avian-Like Features

In a PNAS paper, a Chinese Academy of Agricultural Sciences-led team identifies genetic and genomic features in reassorted Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses that may inform future monitoring strategies for the virus, which has been previously reported in pigs and humans in Europe and China. In particular, the researchers characterized an EA H1N1 strain found in pigs in China that appears pathogenic in mice and transmits between ferrets, using genome sequencing and reassorted mutant testing in animal models to focus in on four main mutations in the acidic polymerase (PA) enzyme-coding gene with apparent effects on viral transcription in their follow-up experiments. "[W]e found that the EA H1N1 virus circulating in swine exhibits increased pathogenicity and transmissibility in mammals, and we further revealed that its accumulated mutations in PA enhance mRNA transcription through different mechanisms and contribute to the harmful properties of the EA H1N1 virus," the authors write. "Our study provides important insights for monitoring field strains with pandemic potential.