In 2019, an outbreak of avian influenza (H3N1) virus infection occurred among commercial poultry in Belgium. Full-genome phylogenetic analysis indicated a wild bird origin rather than recent circulation among poultry. Although classified as a nonnotifiable avian influenza virus, it was associated with reproductive tropism and substantial mortality in the field.
Keywords: Belgium; H3N1; Low pathogenicity avian influenza; highly pathogenic avian influenza; influenza; non-notifiable; outbreak; poultry; respiratory infections; viruses.