A cross-sectional approach to identification & interrogation of adaptive & functional mutations affecting CCHFV replication & pathogenicity in humans

克里米亚-刚果出血热（CCHF）是传播最广的与蜱虫相关的病毒性出血病。该病的临床表现从无症状到导致高发病率和死亡率的严重出血热不等。CCHF的病原体是CCHF正鼻病毒（CCHFV），它是一种具有三方负义RNA基因组的奈罗病毒科成员。除了病毒聚合酶的高错误率带来的遗传漂变外，片段重组和片段之间和片段内的重组提供了巨大的基因组多样性机会，使这些病毒能够适应，利用变化的条件和新的环境利基。在这种广泛的基因组多样性和临床表现范围内，我们预计病毒的遗传决定因素有助于其对人类的致病性。尽管没有明确的证据。在本研究计划中，我们旨在确定CCHFV遗传多样性在人类致病性中的病毒学意义。我们假设，人类感染的CCHFV在从蜱虫或脊椎动物宿主引入后经历了明显的遗传变异，以适应这种新的环境，并且由此产生的突变改变了病毒的复制能力，从而改变了病毒在人类中的毒力。为此目的，该项目将侧重于以下工作包；1. 鉴定在人类分离株中特异性发生的氨基酸突变。2. 追踪人间病例中CCHFV突变的出现情况。3. 鉴定突变的实验评估。这些结果将有助于更好地了解与人感染CCHFV相关的致病性分子机制。此外，来自各种蜱类样本和人类感染的序列数据将有助于更好地了解CCHFV在人类感染和宿主蜱中传播过程中的进化。此外，这些结果将为针对CCHFV的潜在靶向疫苗和抗病毒药物提供信息。

Crimean-Congo haemorrhagic fever (CCHF) is the most widespread tick-associated viral haemorrhagic disease. Clinical presentation of the disease ranges from non-symptomatic to severe haemorrhage fever leading to a high degree of morbidity and death. The agent of CCHF is the virus CCHF orthonairovirus (CCHFV), a member of the Nairoviridae family with a tripartite negative sense RNA genome. Segment reassortment and recombination between and within segments in addition to genetic drift brought about by the high error rate of the viral polymerase, provides an enormous diversity of genome opportunities, which enables these viruses to adapt, exploit varying conditions and new environmental niches. Within this broad genomic diversity and range in clinical presentation, we expect that genetic determinants of the virus contribute to its pathogenicity in humans. Although no clear evidence is available.In this research proposal, we aim to determine the virological significance of genetic diversities of CCHFV in human pathogenicity. We hypothesize that CCHFV in humans undergoes distinct genetic variation after introduction from tick or vertebrate hosts, in order to adapt to this new environment, and that the resulting mutations modify viral replication capacities and subsequently virulence in humans.To this end, the project will focus on the following work packages; 1. Identification of amino acid mutations that have occurred specifically in human isolates. 2. Tracking the emergence of mutations on CCHFV in human cases. 3. Experimental evaluation of the identified mutations.These results will provide insight into a better understanding of the molecular mechanisms of pathogenicity associated with CCHFV in humans. Additionally, sequence data from various tick samples and human infections will support a better understanding of CCHFV evolution during infection in human and circulation in host ticks. Furthermore, these results will provide information for the potential targeting of vaccines and antivirals against CCHFV.