We found highly pathogenic avian influenza A(H5N1) virus clade 2.3.4.4b associated with meningoencephalitis in a stranded harbor porpoise (Phocoena phocoena). The virus was closely related to strains responsible for a concurrent avian influenza outbreak in wild birds. This case highlights the potential risk for virus spillover to mammalian hosts.
Keywords: H5N1 subtype; Phocoena; Sweden; influenza; influenza A virus; influenza in birds; mammals; meningitis/encephalitis; pathology; porpoises; viruses; wild animals; zoonoses.