Confirmed instances of avian influenza viruses infecting humans since 1997 include :

1997: In Hong Kong, avian influenza A (H5N1) infected both chickens and humans. This was the first time an avian influenza virus had ever been found to transmit directly from birds to humans. During this outbreak, 18 people were hospitalized and 6 of them died.

1999: In Hong Kong, cases of avian influenza A (H9N2) were confirmed in 2 children. Both patients recovered, and no additional cases were confirmed. The evidence suggested that poultry was the source of infection and the main mode of transmission was from bird to human.

2003: Two cases of avian influenza A (H5N1) infection occurred among members of a Hong Kong family that had traveled to China. One person recovered, the other died. How or where these 2 family members were infected was not determined. Another family member died of a respiratory illness in China, but no testing was done. No additional cases were reported.

2003: Avian influenza A (H7N7) infections among poultry workers and their families were confirmed in the Netherlands during an outbreak of avian flu among poultry. More than 80 cases of H7N7 illness were reported (the symptoms were mostly confined to eye infections, with some respiratory symptoms), and 1 patient died (in a veterinarian who had visited an affected farm). There was evidence of some human-to-human transmission.

2003: H9N2 infection was confirmed in a child in Hong Kong. The child was hospitalized but recovered.