Abstract Title
Highly Pathogenic Avian Influenza H5 clade 2.3.4.4b viruses in White-Tailed Eagles in Norway
Abstract
Since 2020, highly pathogenic avian influenza viruses (HPAIVs) from the Goose/Guangdong lineage H5 clade 2.3.4.4b have become widespread among wild birds in Norway. From December 2021 to December 2022, white-tailed eagles (Halieetus albicilla, WTEs) represented nearly 30% of all positive HPAIV cases in Norway, suggesting that WTEs are susceptible and particularly exposed to infection. This observation led us to investigate the role of WTEs as potential sentinels for HPAIV circulation in Norway by examining the genomic diversity, phylogenetic relationships, and pathological effects of HPAIV infection in this species.
Whole genome sequencing of HPAIVs was performed on samples from wild birds with sufficient viral loads. The sequences were used for genotyping and further analyzed for their relatedness to HPAIVs globally. Macroscopic and microscopic analyses were performed on carcasses, followed by RNAscope™ to detect viral presence in different tissues.
The detection of HPAIV H5N5 (Eurasian genotype I) in a WTE in February 2022 marked the first recorded case of this subtype in Norway. In addition, phylogenetic analyses revealed at least two distinct introductions of the H5N1 Eurasian genotype C into Norway. Not all genotypes circulating among other wild birds were recovered in WTEs. Post-mortem examinations of four WTEs indicated systemic infection through microscopic analyses, although no gross macroscopic pathological changes were observed.
Our findings highlight the potential role of WTEs as sentinels for monitoring HPAIV circulation. However, the absence of several known genotypes in WTEs suggests variability in the susceptibility and pathogenic effects of different HPAIV strains on this species.
Whole genome sequencing of HPAIVs was performed on samples from wild birds with sufficient viral loads. The sequences were used for genotyping and further analyzed for their relatedness to HPAIVs globally. Macroscopic and microscopic analyses were performed on carcasses, followed by RNAscope™ to detect viral presence in different tissues.
The detection of HPAIV H5N5 (Eurasian genotype I) in a WTE in February 2022 marked the first recorded case of this subtype in Norway. In addition, phylogenetic analyses revealed at least two distinct introductions of the H5N1 Eurasian genotype C into Norway. Not all genotypes circulating among other wild birds were recovered in WTEs. Post-mortem examinations of four WTEs indicated systemic infection through microscopic analyses, although no gross macroscopic pathological changes were observed.
Our findings highlight the potential role of WTEs as sentinels for monitoring HPAIV circulation. However, the absence of several known genotypes in WTEs suggests variability in the susceptibility and pathogenic effects of different HPAIV strains on this species.
Co-Author(s)
Cathrine Arnason Bøe1, Eve Marie Louise Zeyl Fiskebeck1, Malin Rokseth Reiten1, Johan Åkerstedt1, Maryam Saghafian1, Ragnhild Tønnessen1, Britt Gjerset1, Kjersti Sturød1, Torfinn Moldal1, Grim Rømo1, Morten Helberg2, Duncan Halley3, Lars-Erik Lundblad Rondestveit4, Knut Madslien1 and Silje Granstad1
1 Norwegian Veterinary Institute
2 BirdLife Norway
3 Norwegian Institute of Nature Research
4 Norwegian Food Safety Authority
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds