Gene

Biology

Virology

Serology

Coronavirus disease 2019 (COVID-19)

Genetics

Genotype

Seroprevalence

Influenza A virus subtype H5N1

Infectious disease (medical specialty)

Medicine

Virus

Pandemic

Influenza A virus

H5N1 genetic structure

Reassortment

Disease

Antibody

Pathology

Proceedings of the National Academy of Sciences

Significance Pigs are intermediate hosts for the generation of pandemic influenza virus. Thus, systematic surveillance of influenza viruses in pigs is a key measure for prewarning the emergence of the next pandemic influenza. Here, we identified a reassortant EA H1N1 virus possessing pdm/09 and TR-derived internal genes, termed as G4 genotype, which has become predominant in swine populations since 2016. Similar to pdm/09 virus, G4 viruses have all the essential hallmarks of a candidate pandemic virus. Of concern is that swine workers show elevated seroprevalence for G4 virus. Controlling the prevailing G4 EA H1N1 viruses in pigs and close monitoring in human populations, especially the workers in swine industry, should be urgently implemented.

Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection