Wallace Robert G, Hodac Hoangminh, Lathrop Richard H, Fitch Walter M
Department of Ecology and Evolutionary Biology, University of California-Irvine, 321 Steinhaus Hall, Irvine, CA 92697, USA.
Proc Natl Acad Sci U S A. 2007 Mar 13;104(11):4473-8. doi: 10.1073/pnas.0700435104. Epub 2007 Mar 7.
The geographic diffusion of highly pathogenic influenza A H5N1 has largely been traced from the perspective of the virus's victims. Birds of a variety of avian orders have been sampled across localities, and their infection has been identified by a general genetic test. Another approach tracks the migration from the perspective of the virus alone, by way of a phylogeography of H5N1 genetic sequences. Although several phylogenies in the literature have labeled H5N1 clades by geographic region, none has analytically inferred the history of the virus's migration. With a statistical phylogeography of 192 hemagglutinin and neuraminidase isolates, we show that the Chinese province of Guangdong is the source of multiple H5N1 strains spreading at both regional and international scales. In contrast, Indochina appears to be a regional sink, at the same time demonstrating bidirectional dispersal among localities within the region. An evolutionary trace of HA(1) across the phylogeography suggests a mechanism by which H5N1 is able to infect repeated cycles of host species across localities, regardless of the host species first infected in each locale. The trace also hypothesizes amino acid replacements that preceded the first recorded outbreak of pathogenic H5N1 in Hong Kong, 1997.
高致病性甲型H5N1流感病毒的地理扩散情况，很大程度上是从病毒受害者的角度进行追踪的。各地对多种鸟类目进行了采样，并通过一般基因检测确定其感染情况。另一种方法是仅从病毒的角度，通过H5N1基因序列的系统发育地理学来追踪其传播。虽然文献中的几种系统发育图谱已按地理区域对H5N1分支进行了标注，但尚无研究对病毒的传播历史进行分析推断。通过对192株血凝素和神经氨酸酶分离株进行统计系统发育地理学分析，我们发现中国广东省是多种H5N1毒株在区域和国际范围内传播的源头。相比之下，印度支那地区似乎是一个区域汇点，同时该地区内部各地之间存在双向传播。对整个系统发育地理学中HA(1)的进化追踪表明，H5N1能够跨越各地反复感染宿主物种，而不论每个地区首次感染的宿主物种是什么。该追踪还推测了1997年香港首次记录到致病性H5N1疫情之前发生的氨基酸替换情况。
