基于离散型地理信息的H7N9流感病毒动态时空传播模式

目的 基于离散型的地理信息构建了H7N9病毒时空动态传播模式图，探索H7N9病毒的空间传播路径。方法 选取全球共享禽流感数据倡议组织（GISAID）中中国以人类为宿主的H7N9流感病毒血凝素（HA）和神经酰胺酶（NA）基因序列，利用BioEdit 7.0软件进行多序列比对。在贝叶斯理论框架下，运用BEAST 1.8.2软件构建H7N9时空传播模型，采用symmetric substitution model和贝叶斯随机搜索变量选择（BBSVS）方法，对H7N9的历史传播轨迹进行推断和检验。以Google Earth软件展现H7N9病毒的时空传播动态图。结果 感染人类的H7N9病毒起源于上海或杭州，最早可追溯到2012年10月。并在2013年3、4月份开始传向邻近省份，同年8、9月份传播加剧，3个月内传向10余处地区。结论 基于基因核苷酸序列和空间地理信息，追踪了H7N9病毒历史传播轨迹，为早期流感疫情的防控及病毒的溯源提供线索。

Research on spatiotemporal spread of avian influenza A(H7N9) virus based on discrete geographic information

Objective To establish a dynamic spatiotemporal spread modes of influenza A(H7N9) virus by using discrete geographic information and explore the spatiotemporal transmission of the virus. Methods The gene sequences of H7N9 virus isolated from human in China, which were available from Global Initiative on Sharing Avian Influenza Data (GISAID), were used in alignment by using software BioEdit 7.0. Spatiotemporal spread model of H7N9 virus was established in a Bayesian statistical framework by using software BEAST 1.8.2. The symmetric substitution model and Bayesian stochastic search variable selection (BSSVS) were used to infer and verify the historical transmission route of H7N9 virus. Finally the spatiotemporal transmission route was presented by Google Earth software. Results The transmission of avian influenza A (H7N9) virus originated in Shanghai and Hangzhou, and can be dated back to October 2012. In March and April 2013, it began to spread to the neighboring provinces. The transmission speed up in August and September and affected more than ten geographic positions within 3 months. Conclusion Based on gene sequences and spatial geographic information, the transmission route of H7N9 virus was traced, which would support the avian influenza prevention and control as well as avian influenza virus tracing.