Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, USA.
U.S. Environmental Protection Agency, Region 10, Seattle, WA 98101, USA.
J Gen Virol. 2022 Mar;103(3). doi: 10.1099/jgv.0.001724.
Intraspecific variation in pathogen shedding impacts disease transmission dynamics; therefore, understanding the host factors associated with individual variation in pathogen shedding is key to controlling and preventing outbreaks. In this study, ileum and bursa of Fabricius tissues of wild-bred mallards () infected with low-pathogenic avian influenza (LPAIV) were evaluated at various post-infection time points to determine genetic host factors associated with intraspecific variation in viral shedding. By analysing transcriptome sequencing data (RNA-seq), we found that LPAIV-infected wild-bred mallards do not exhibit differential gene expression compared to uninfected birds, but that gene expression was associated with cloacal viral shedding quantity early in the infection. In both tissues, immune gene expression was higher in high/moderate shedding birds compared to low shedding birds, and significant positive relationships with viral shedding were observed. In the ileum, expression for host genes involved in viral cell entry was lower in low shedders compared to moderate shedders at 1 day post-infection (DPI), and expression for host genes promoting viral replication was higher in high shedders compared to low shedders at 2 DPI. Our findings indicate that viral shedding is a key factor for gene expression differences in LPAIV-infected wild-bred mallards, and the genes identified in this study could be important for understanding the molecular mechanisms driving intraspecific variation in pathogen shedding.
种内病原体脱落的变异会影响疾病传播动态；因此，了解与个体病原体脱落变异相关的宿主因素是控制和预防疫情爆发的关键。在这项研究中，在感染低致病性禽流感 (LPAIV) 的野生斑鸭的回肠和法氏囊组织中，在不同的感染后时间点进行评估，以确定与种内病毒脱落变异相关的遗传宿主因素。通过分析转录组测序数据 (RNA-seq)，我们发现感染 LPAIV 的野生斑鸭与未感染鸟类相比没有表现出差异表达的基因，但基因表达与感染早期的泄殖腔病毒脱落量有关。在两种组织中，高/中度脱落鸟类的免疫基因表达均高于低脱落鸟类，并且与病毒脱落呈显著正相关。在回肠中，与病毒细胞进入相关的宿主基因在低脱落者中 1 天感染后 (DPI) 表达低于中脱落者，而促进病毒复制的宿主基因在高脱落者中 2 DPI 时表达高于低脱落者。我们的研究结果表明，病毒脱落是 LPAIV 感染野生斑鸭基因表达差异的关键因素，本研究中鉴定的基因可能对理解驱动病原体脱落种内变异的分子机制很重要。
