The European Centre for Disease Prevention and Control (ECDC) has published a threat assessment brief concerning Eurasian avian-like A(H1N1) swine influenza viruses. The 2009 pandemic was the latest of several pandemics caused by a swine-origin influenza virus.
The ECDC assessment reports that a study conducted between 2011 and 2018 in China, based on surveillance data in pigs, identified an emerging genotype 4 (G4) reassortant Eurasian avian-like (EA) A(H1N1) swine influenza virus, which contains internal genes from the human A(H1N1)pdm09 and North American triple-reassortant (TR) lineage-derived internal genes. This virus demonstrated the ability to replicate in human epithelial cells, and can spread through respiratory droplets between ferrets. Antisera against seasonal human A(H1N1)pdm09 virus showed poor reactivity with G4 viruses. In the same study, a subsequent serosurvey found that 10% (35/338) of swine farm workers tested positive for this G4 EA A(H1N1) virus, with a higher proportion being among people aged between 18 and 35 years of age.
Source: ECDC, 13 July 2020