Department of Poultry Diseases, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Puławy, Poland.
Department of Omics Analyses, National Veterinary Research Institute, Al. Partyzantów 57, 24-100 Puławy, Poland.
Viruses. 2020 Mar 16;12(3):319. doi: 10.3390/v12030319.
Avian influenza virus (AIV) is a highly diverse and widespread poultry pathogen. Itsevolution and adaptation may be affected by multiple host and ecological factors, which are stillpoorly understood. In the present study, a turkey-origin H9N2 AIV was used as a model toinvestigate the within-host diversity of the virus in turkeys, quail and ducks in conjunction with theclinical course, shedding and seroconversion. Ten birds were inoculated oculonasally with a doseof 106 EID50 of the virus and monitored for 14 days. Virus shedding, transmission andseroconversion were evaluated, and swabs collected at selected time-points were characterized indeep sequencing to assess virus diversity. In general, the virus showed low pathogenicity for theexamined bird species, but differences in shedding patterns, seroconversion and clinical outcomewere noted. The highest heterogeneity of the virus population as measured by the number of singlenucleotide polymorphisms and Shannon entropy was found in oropharyngeal swabs from quail,followed by turkeys and ducks. This suggests a strong bottleneck was imposed on the virus duringreplication in ducks, which can be explained by its poor adaptation and stronger selection pressurein waterfowl. The high within-host virus diversity in quail with high level of respiratory sheddingand asymptomatic course of infection may contribute to our understanding of the role of quail asan intermediate host for adaptation of AIV to other species of poultry. In contrast, low viruscomplexity was observed in cloacal swabs, mainly from turkeys, showing that the within-hostdiversity may vary between different replication sites. Consequences of these observations on thevirus evolution and adaptation require further investigation.
禽流感病毒（AIV）是一种高度多样化和广泛存在的家禽病原体。其进化和适应可能受到多种宿主和生态因素的影响，这些因素仍了解甚少。在本研究中，以一株来源于火鸡的 H9N2 AIV 为模型，结合临床病程、排毒和血清转化，研究了病毒在火鸡、鹌鹑和鸭子体内的多样性。将 10 只禽类经眼鼻接种 106 EID50 的病毒剂量，并监测 14 天。评估病毒的排毒、传播和血清转化情况，并在选定的时间点采集拭子进行深度测序，以评估病毒的多样性。总的来说，该病毒对所检查的鸟类物种表现出低致病性，但在排毒模式、血清转化和临床结果方面存在差异。在鹌鹑的口咽拭子中发现病毒种群的最高异质性，以单核苷酸多态性和香农熵的数量衡量，其次是火鸡和鸭子。这表明病毒在鸭子体内复制过程中受到了强烈的瓶颈限制，这可以用其在水禽中的适应性差和更强的选择压力来解释。在呼吸道排毒水平高且感染过程无症状的鹌鹑中，病毒的体内多样性较高，这可能有助于我们理解鹌鹑作为 AIV 适应其他家禽物种的中间宿主的作用。相比之下，在主要来自火鸡的泄殖腔拭子中观察到的病毒复杂性较低，这表明体内多样性可能在不同的复制部位之间有所不同。这些观察结果对病毒进化和适应的影响需要进一步研究。
