[Avian influenza viruses--new causative agents of human infections].

Introduction: Influenza A viruses can infect humans, some mammals and especially birds. Subtypes of human influenza A viruses: A(H1N1), A(H2N2) and A(H3N2) have caused pandemics. Avian influenza viruses vary owing to their 15 hemagglutinins (H) and 9 neuraminidases (N).