| Open Access
Rapid evolution of A(H5N1) influenza viruses after intercontinental spread to North America
Highly pathogenic avian influenza A(H5N1) viruses of clade 18.104.22.168b underwent an explosive geographic expansion in 2021 among wild birds and domestic poultry. Here, Kandeil et al. show that the Western movement of this clade was followed by reassortment with viruses circulating in wild birds in North America which resulted in different genotypes exhibiting a wide range of disease severity in mammal models (mice, ferrets, chicken) ranging from asymptomatic disease to severe neurological pathology.