tetano
Editor, Senior Moderator
Vet Pathol
. 2026 Nov 3:3009858261500105.
doi: 10.1177/03009858261500105. Online ahead of print.
Georg Beythien 1 , Hannah Gerhards 1 , Martin Peters 2 , Jochen Kilwinski 2 , Pauline Pöpperl 1 , Inga Nägler 1 , Ann Kathrin Ahrens 3 , Anne Pohlmann 3 , Martin Beer 3 , Wolfgang Baumgärtner 1 , Peter Wohlsein 1
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In late 2025, Germany faced a major outbreak of highly pathogenic influenza virus subtype H5N1 clade 2.3.4.4b, causing high mortality in migratory and resident wild birds and poultry. We examined 16 deceased birds, including Eurasian cranes, geese, a teal, and raptors found in western Germany between October and December 2025. Here, we provide a comparative analysis of light microscopic findings using histology and viral antigen distribution determined by immunohistochemistry, alongside the underlying viral phylogeny. Lesions and viral antigen distribution varied by species, with cranes showing infection in a broad organ spectrum, including the central nervous system (CNS), pancreas, spleen, liver, and kidneys, whereas other species exhibited a more targeted organ involvement. Phylogenetic analysis identified the EA-2024-DI.2.1 sublineage, with cranes forming a monophyletic cluster, which was consistent with the shared roosting/migratory behavior of cranes, although epidemiologic links were not formally demonstrated. In summary, our findings indicate species-specific lesion patterns and viral tissue tropism, which may influence transmission dynamics and environmental shedding.
Keywords: HPAIV H5N1 clade 2.3.4.4b; avian; highly pathogenic avian influenza virus (HPAIV) H5; histopathology; immunohistochemistry; migratory and resident wild birds; western Germany.
. 2026 Nov 3:3009858261500105.
doi: 10.1177/03009858261500105. Online ahead of print.
Highly pathogenic avian influenza H5N1-species-specific histopathology and viral antigen distribution in migratory and resident wild birds, South Westphalia, Germany 2025
Georg Beythien 1 , Hannah Gerhards 1 , Martin Peters 2 , Jochen Kilwinski 2 , Pauline Pöpperl 1 , Inga Nägler 1 , Ann Kathrin Ahrens 3 , Anne Pohlmann 3 , Martin Beer 3 , Wolfgang Baumgärtner 1 , Peter Wohlsein 1
Affiliations Expand
- PMID: 42978374
- DOI: 10.1177/03009858261500105
Abstract
In late 2025, Germany faced a major outbreak of highly pathogenic influenza virus subtype H5N1 clade 2.3.4.4b, causing high mortality in migratory and resident wild birds and poultry. We examined 16 deceased birds, including Eurasian cranes, geese, a teal, and raptors found in western Germany between October and December 2025. Here, we provide a comparative analysis of light microscopic findings using histology and viral antigen distribution determined by immunohistochemistry, alongside the underlying viral phylogeny. Lesions and viral antigen distribution varied by species, with cranes showing infection in a broad organ spectrum, including the central nervous system (CNS), pancreas, spleen, liver, and kidneys, whereas other species exhibited a more targeted organ involvement. Phylogenetic analysis identified the EA-2024-DI.2.1 sublineage, with cranes forming a monophyletic cluster, which was consistent with the shared roosting/migratory behavior of cranes, although epidemiologic links were not formally demonstrated. In summary, our findings indicate species-specific lesion patterns and viral tissue tropism, which may influence transmission dynamics and environmental shedding.
Keywords: HPAIV H5N1 clade 2.3.4.4b; avian; highly pathogenic avian influenza virus (HPAIV) H5; histopathology; immunohistochemistry; migratory and resident wild birds; western Germany.