In the past, only a few bacterial infections have been reported, caused by other patogenic viruses: in South Africa in 1961 (H5N3) and in Hong Kong in 2002-03 (H5N1).
In passato sono state registrate solo due consistenti more di uccelli migratori, provocate da virus altamente patogenici: in Sudafrica nel 1961 (H5N3) e a Hong Kong nell’inverno 2002-03 (H5N1).