Wageningen University and Research - Wageningen Bioveterinary Research, Lelystad, The Netherlands.
Emerg Microbes Infect. 2021 Dec;10(1):97-108. doi: 10.1080/22221751.2020.1868274.
Strategies to control spread of highly pathogenic avian influenza (HPAI) viruses by wild birds appear limited, hence timely characterization of novel viruses is important to mitigate the risk for the poultry sector and human health. In this study we characterize three recent H5-clade 2.3.4.4 viruses, the H5N8-2014 group A virus and the H5N8-2016 and H5N6-2017 group B viruses. The pathogenicity of the three viruses for chickens, Pekin ducks and Eurasian wigeons was compared. The three viruses were highly pathogenic for chickens, but the two H5N8 viruses caused no to mild clinical symptoms in both duck species. The highest pathogenicity for duck species was observed for the most recent H5N6-2017 virus. For both duck species, virus shedding from the cloaca was higher after infection with group B viruses compared to the H5N8-2014 group A virus. Higher cloacal virus shedding of wild ducks may increase transmission between wild birds and poultry. Environmental transmission of H5N8-2016 virus to chickens was studied, which showed that chickens are efficiently infected by (fecal) contaminated water. These results suggest that pathogenicity of HPAI H5 viruses and virus shedding for ducks is evolving, which may have implications for the risk of introduction of these viruses into the poultry sector.
控制野生鸟类传播高致病性禽流感（HPAI）病毒的策略似乎有限，因此及时鉴定新型病毒对于减轻家禽业和人类健康的风险非常重要。在本研究中，我们对三种最近的 H5 谱系 2.3.4.4 病毒、H5N8-2014 组 A 病毒和 H5N8-2016 和 H5N6-2017 组 B 病毒进行了特征描述。比较了这三种病毒对鸡、北京鸭和欧亚泽凫的致病性。三种病毒对鸡具有高致病性，但两种 H5N8 病毒在两种鸭种中均未引起或仅引起轻微临床症状。对鸭种而言，最新的 H5N6-2017 病毒的致病性最高。对于这两种鸭种，感染组 B 病毒后的泄殖腔病毒脱落量高于感染 H5N8-2014 组 A 病毒。野鸭泄殖腔中更高的病毒脱落可能会增加野鸟和家禽之间的传播。研究了 H5N8-2016 病毒对鸡的环境传播，结果表明鸡可通过（粪便）污染的水被有效感染。这些结果表明，HPAI H5 病毒的致病性和对鸭的病毒脱落量正在发生演变，这可能会对这些病毒引入家禽业的风险产生影响。
