Abstract Title
Between East and West: Molecular surveillance of highly pathogenic avian influenza viruses in wild birds in Germany
Abstract
The risk of highly pathogenic avian influenza (HPAI) to wild bird populations is a major concern, particularly in areas where migratory routes converge. Germany, located at a major crossroads for European bird migration, represents a critical hotspot for the spread of HPAI among wild bird populations. The enzootic nature of HPAI worldwide leads to outbreaks throughout the year, and tracking the emergence and spread of viruses has become increasingly important. We have identified a plethora of virus genotypes, each with different genome segment composition, during the avian influenza enzootic period. We investigated die-offs of wild birds in German coastal regions during the breeding season in the summers of 2022, 2023 and 2024 and found significant differences in virus spread patterns. Two genotypes (21-10-N1.2_euC2 and 21-10-N1.5_euAB) were detected in outbreaks in gannets and terns in 2022, each showing a completely different spread. One was found as far north as Iceland and spread westwards to North America. In the summer of 2023, a genetically distinct gull-adapted genotype (23-02-N1.1_euBB) caused die-offs in colonies of black-headed gulls in protected areas in the Baltic Sea. In Germany, this genotype was completely displaced in September 2023, and in November 2023, new H5N1 viruses emerged. One of these (24-03-N1.1_euDI) has been detected in south-eastern Europe since winter 2023/2024. Wild birds in protected areas in the Baltic Sea were again affected by HPAI viruses of this genotype in summer 2024. In summary, the differences in spread of HPAI viruses underline the importance of molecular surveillance.
Co-Author(s)
Anne Pohlmann, Ann Kathrin Ahrens, Anne Günther, Christian Grund, Martin Beer, Timm Harder
Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds