In the spring of 2006 we had our first outbreak of avian influenza of highly pathogenic H5N1 (HPAI) among wild birds in Sweden. This disease have impact on poultry industries world wide. Sporadically the virus infects other species than birds and we now know it can even cause fatal infection of humans. There are not yet any confirmed cases of transmission of the disease between humans though a suspected case in an Indonesian family is under investigation. If a mutation occurs that changes the pathogenicity and host affinity to humans we are at a risk of a new pandemia, perhaps like the Spanish flu in 1918-1920.