In the present paper basic data on the influenza viruses and their antigens are summarized. Over the last years the virus of influenza with hemagglutinin H1-3, neuraminidase N1, N2, N8 was demonstrated in humans. Birds represent a natural reservoir of influenza A virus. Since 1959, 24 epizootias were recorded in the world. At the present time human diseases began to appear in connection with the spreading of bird influenza H5N1. Until 19th April 2006 World Health Organization confirmed 196 diseases, 110 of them ending by death of the patients. In view of the possible adaptation of the bird influenza viruses to the spreading of infection in humans it is necessary to analyze further development with great care. For the cases of pandemia a specific pandemia plan has been elaborated in the Czech Republic.

        Key words: bird influenza, transfer, pandemia