Germany and Europe are at the beginning of another severe wave of avian influenza. Since mid-October 2021, hundreds of infected wild birds and more than 50 outbreaks in poultry and kept birds have been reported in Germany from numerous federal states. H5N1 is the predominant virus subtype. The Friedrich-Loeffler-Institut (FLI) still classifies the risk of a spread of avian influenza subtype H5 among wild birds and of a transmission to poultry and kept birds in Germany as high. It is again urgently recommended to keep biosafety measures in poultry holdings at a high level and, if necessary, to further intensify them.
What has changed in this epizootic is that despite a significant reduction of outbreaks, cases continued to occur in wild birds, particularly in Northern Europe, last summer. Genetic analyses indicate that the viruses circulating in Europe since October 2020 ‘oversummered’ last year and that in addition closely related but distinguishable H5N1 viruses have been introduced from the East from September/October 2021 on.
In case of a continuous circulation of avian influenza viruses in wild birds (endemic situation), it will become necessary to discuss additional protection measures for poultry to be implemented in the medium to long run. In the medium term, from the FLI’s point of view, a reduction in the density of commercial poultry farms through restocking bans could be considered. This would be especially important in densely populated poultry farming regions and in the vicinity of wetlands. In the long term, the restructuring of poultry production systems that are particularly susceptible to avian influenza should be considered as soon as an endemic situation has been reached. This will minimize the risk of an introduction and further spread of the virus. In addition, the availability of vaccines and scenarios for their possible use should be assessed.
It will not be possible before next summer/autumn to assess whether the avian influenza situation will reach an endemic status or the oversummering of the pathogen last year rather was an exception.