Piesche Ronja, Breithaupt Angele, Pohlmann Anne, Ahrens Ann Kathrin, Beer Martin, Harder Timm, Grund Christian
Friedrich- Loeffler- Institute, Institute of Diagnostic Virology, Greifswald, Germany.
Friedrich- Loeffler- Institute, Department of Experimental Animal Facilities and Biorisk Management (ATB), Greifswald, Germany.
Npj Viruses. 2024 Nov 6;2(1):53. doi: 10.1038/s44298-024-00062-0.
Highly pathogenic avian influenza viruses (HPAIV) of H5 clade 2.3.4.4b pose an ongoing threat worldwide. It remains unclear whether this panzootic situation would favor low virulent phenotypes expected by the 'avirulence hypothesis' of viral evolution. Assessing virulence in Pekin ducklings in an intramuscular infection model revealed that the two genotypes that dominated the epidemiological situation in Germany during the period 2021 and 2022 (EU-RL:CH and EU-RL:AB) were of high virulence. In contrast, rare genotypes were of intermediate virulence. The genetic constellation of these reassortants pointed to an important role of the viral polymerase complex (RdRP), particularly the PB1 genome segment, in shaping virulence in ducklings. Occulo-nasal infection of ducklings confirmed the phenotypes for two representative viruses and indicated a more efficient replication for the high virulence strain. These observations would be in line with the 'virulence-transmission trade-off' model for describing HPAIV epidemiology in wild birds in Germany.
H5进化分支2.3.4.4b的高致病性禽流感病毒（HPAIV）在全球范围内构成持续威胁。目前尚不清楚这种大流行情况是否会有利于病毒进化的“无毒力假说”所预期的低毒力表型。在肌肉感染模型中对北京鸭雏鸭的毒力评估显示，在2021年至2022年期间主导德国流行病学情况的两种基因型（欧盟参考实验室：CH和欧盟参考实验室：AB）具有高毒力。相比之下，罕见基因型具有中等毒力。这些重配体的基因组合表明病毒聚合酶复合体（RdRP），特别是PB1基因组片段，在塑造雏鸭毒力方面发挥着重要作用。对雏鸭进行眼鼻感染证实了两种代表性病毒的表型，并表明高毒力毒株的复制效率更高。这些观察结果与描述德国野生鸟类中HPAIV流行病学的“毒力-传播权衡”模型一致。
