Patuxent Wildlife Research Center, United States Geological Survey, Beltsville, Maryland, United States of America.
PLoS One. 2011 Mar 9;6(3):e17622. doi: 10.1371/journal.pone.0017622.
Qinghai Lake in central China has been at the center of debate on whether wild birds play a role in circulation of highly pathogenic avian influenza virus H5N1. In 2005, an unprecedented epizootic at Qinghai Lake killed more than 6000 migratory birds including over 3000 bar-headed geese (Anser indicus). H5N1 subsequently spread to Europe and Africa, and in following years has re-emerged in wild birds along the Central Asia flyway several times.
METHODOLOGY/PRINCIPAL FINDINGS: To better understand the potential involvement of wild birds in the spread of H5N1, we studied the movements of bar-headed geese marked with GPS satellite transmitters at Qinghai Lake in relation to virus outbreaks and disease risk factors. We discovered a previously undocumented migratory pathway between Qinghai Lake and the Lhasa Valley of Tibet where 93% of the 29 marked geese overwintered. From 2003-2009, sixteen outbreaks in poultry or wild birds were confirmed on the Qinghai-Tibet Plateau, and the majority were located within the migratory pathway of the geese. Spatial and temporal concordance between goose movements and three potential H5N1 virus sources (poultry farms, a captive bar-headed goose facility, and H5N1 outbreak locations) indicated ample opportunities existed for virus spillover and infection of migratory geese on the wintering grounds. Their potential as a vector of H5N1 was supported by rapid migration movements of some geese and genetic relatedness of H5N1 virus isolated from geese in Tibet and Qinghai Lake.
CONCLUSIONS/SIGNIFICANCE: This is the first study to compare phylogenetics of the virus with spatial ecology of its host, and the combined results suggest that wild birds play a role in the spread of H5N1 in this region. However, the strength of the evidence would be improved with additional sequences from both poultry and wild birds on the Qinghai-Tibet Plateau where H5N1 has a clear stronghold.
中国中部的青海湖一直是关于野生鸟类是否在传播高致病性禽流感病毒 H5N1 方面发挥作用的争论焦点。2005 年，青海湖发生了一场空前的疫病，导致包括 3000 多只斑头雁（Anser indicus）在内的 6000 多只候鸟死亡。H5N1 随后传播到欧洲和非洲，随后几年，沿中亚迁徙路线的野生鸟类中多次出现该病毒。
方法/主要发现：为了更好地了解野生鸟类在 H5N1 传播中的潜在作用，我们研究了在青海湖用 GPS 卫星发射器标记的斑头雁的迁徙与病毒爆发和疾病风险因素之间的关系。我们发现了一条以前未被记录的迁徙路线，从青海湖到西藏的拉萨河谷，29 只标记的斑头雁中有 93%在那里越冬。2003 年至 2009 年，在青藏高原上确认了 16 起家禽或野生鸟类的疫情，其中大部分位于鹅的迁徙路线上。鹅的迁徙与三个潜在的 H5N1 病毒源（家禽养殖场、一个圈养斑头鹅设施和 H5N1 疫情发生地）的时空一致性表明，病毒溢出和迁徙鹅感染的机会很多在冬季栖息地。一些鹅的快速迁徙运动以及从西藏和青海湖的鹅中分离出的 H5N1 病毒的遗传亲缘关系支持它们作为 H5N1 病毒载体的作用。
结论/意义：这是首次将病毒的系统发生与宿主的空间生态学进行比较的研究，综合结果表明，野生鸟类在该地区 H5N1 的传播中发挥了作用。然而，如果在青藏高原上有更多来自家禽和野生鸟类的序列，那么证据的力度将会增强，在青藏高原上 H5N1 有一个明显的据点。
