No abstract

No abstract

No abstract

P igs have long been considered a crucial genetic mixing vessel for influenza A viruses (IAVs) of different hosts (1) because of the dual expression of human (SAα-2,6Gal) and avian (SAα-2,3Gal) viral receptors on their respiratory epithelium. Swine IAVs such as H1N1 and H3N2 subtypes sporadically infect humans and are prone to cause bidirectional interspecies transmission at the swine-human interface (2-5). So far, Eurasian avian-like (EA) H1N1 has dominated prevalence in pig herds in China and caused >10 human infections (6-9). In particular, the dominant genotype 4 (G4) EA H1N1 containing 2009 pandemic influenza A(H1N1) polymerase basic (PB) 1 and 2, polymerase acid (PA), nucleoprotein (NP), and matrix (M) genes, plus the triple-reassortant (TR) nonstructural (NS) gene, is thought to be a candidate virus of potential pandemic (10,11). Indeed, a case of human infection with G4 EA H1N1 was reported in Yunan Province, China, in 2021 (8). It is imperative to conduct surveillance on swine IAVs and evaluate their risk to public health.