我国H9N2亚型禽流感病毒适应性(Fitness)建模研究

H9N2亚型禽流感病毒在我国广泛分布，是当前禽流感流行的主要亚型，该病毒呈现持续变异。近年来报道的超过5种亚型（H5N1，H7N9，H10N8，H6N1和H5N6）的禽流感病毒感染人的疫情或案例中，进化溯源显示其起源几乎都是由它们的祖先病毒通过与我国的H9N2禽流感病毒重配而产生的。H9N2病毒对我国构成严重威胁，然而对该病毒的适应性进化研究尤其是重配对病毒适应性的影响还不够深入。本课题拟利用现有H9N2禽流感病毒基因组数据和流行病学数据，研究影响我国H9N2禽流感病毒适应性的关键因素，重点分析重配事件在H9N2病毒适应性进化过程中的重要作用，同时建立基于单一基因节段和多基因节段耦合协同作用的H9N2禽流感适应性量化模型，为我们理解H9N2流感病毒在我国广泛存在的适应性进化及其作为重配背景模版的相关机制打下一定的理论基础，探索建立基于基因组数据的H9N2禽流感病毒适应性预测和评估方法。

The H9N2 subtype of avian influenza virus (AIV) is widely distributed in China and is a major subtype of the current avian influenza. It is currently the main subtype AIV in China. The virus has shown persistent genetic diversities. More than 5 subtypes (H5N1, H7N9, H10N8, H6N1 and H5N6) of AIVs that recently infected human was almost exclusively caused by the reassortment of their ancestral viruses with the H9N2 AIVs in China. The virus poses a serious threat to the health of the people in China. However, the study on the fitness of the virus, especially the impact of reassortment on the adaptability of the virus, is still insufficient. In this project, we intend to study the main factors that affect the fitness of the H9N2 virus in China, focusing on the analysis of the effects contributed by the reassortment events in the adaptive evolution of H9N2 virus. We will establish a fitness model of the H9N2 AIVs based on both the synergistic effect of single gene and the multi-gene segments coupling interactions. This study may contribute to the theoretical foundation for understanding the adaptive evolution of H9N2 influenza virus in China and its mechanism as a reassortment background template. We will try to build a methodology to predict and evaluate the fitness of H9N2 AIVs based on genomic data.