Duck migration and past influenza A (H5N1) outbreak areas

In 2005 and 2006, the highly pathogenic avian influenza (HPAI) virus subtype H5N1 rapidly spread from Asia through Europe, the Middle East, and Africa. Waterbirds are considered the natural reservoir of low pathogenic avian influenza viruses (1), but their potential role in the spread of HPAI (H5N1), along with legal and illegal poultry and wildlife trade (2), is yet to be clarified.