Concurrent detection of swine-origin H1N1 Influenza A virus in pigs and a farmer in Switzerland
Zoonotic transmission events of Influenza A Viruses (IAV) at the pig-human interface pose an important risk for the emergence of novel IAV variants with pandemic potential. Therefore, continuous epidemiological and genomic surveillance of such variants is essential for pandemic preparedness.   As part of a Swiss multidisciplinary research consortium, we report here the pig-to-human transmission of swine H1N1 (swH1N1) from a pig herd to their caretaker, who both presented with influenza-like symptoms. Nasal swab samples were confirmed to be positive for IAV by RT-qPCR. Whole-genome sequencing revealed more than 99.9% sequence identity in both hosts. These strains were confirmed to belong to the swH1N1 Eurasian-avian lineage, clade 1C.2.2, forming a unique monophyletic Swiss cluster.    This case study provides strong evidence of pig-human swH1N1 transmission and underlines the zoonotic potential of enzootic swine IAVs. Although onward human-human transmission was unconfirmed, such events raise concern for pandemic potential of zoonotic variants. Our findings emphasize the need for active One Health surveillance integrating epidemiological and genomics data to enable early detection of emerging health threats and strengthen pandemic preparedness.