This A/H5N1 group has shown itself to be unusually stable for an avian influenza strain and has spread among birds in two waves, the second of which took it out of south and south-east Asia to Europe and Africa through migratory birds and trade.
A/H5N1-tüvi on osutunud linnugripi tüve kohta ebatavaliselt püsivaks ning on levinud lindude seas kahe lainena, millest teise käigus levis Lõuna- ja Kagu-Aasiast rändlindude ja kaupadega Euroopasse ja Aafrikasse.