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蚊子交叉叮咬可能助北美西尼罗病毒快速传播
而在欧洲,两个不同亚种的尖音库蚊(Culex pipiens)搭载着这一病毒,其中一种叮咬人类,另一种以叮咬鸟类为生。
华盛顿国家自然历史博物馆的封塞卡(Dina Fonseca)和同事指出,上述差异可能解释了为何欧洲的西尼罗病毒疫情相对规模较小。
与欧洲的情况不同,西尼罗病毒横扫了北美大陆,导致大量乌鸦和松鸦类禽鸟死亡,还有数百人丧生。
西尼罗病毒首次于1999年在纽约市被发现,当时感染了62人。去年,该病毒在美国感染了9,300人,导致240人死亡;加拿大约有1,300人受感染,10人丧生;另外墨西哥也有传出病例。
“与欧洲尖音库蚊不同,美国的尖音库蚊似乎很容易既叮咬鸟类,也叮咬人类,”封塞卡的研究小组在报告中写道。研究报告发表在3月5日出刊的《科学》(Science)杂志上。
研究者称,交叉叮咬的蚊子加上迁徙候鸟的感染以及稠密的城市人口,这些因素可能为病毒的快速传播创造了条件。
Emerging vectors in the Culex pipiens complex.
In the Old World, some mosquitoes in the Culex pipiens complex are excellent enzootic vectors of West Nile virus, circulating the virus among birds, whereas others bite mainly humans and other mammals. Here we show that, in northern Europe, such forms differing in behavior and physiology have unique microsatellite fingerprints with no evidence of gene flow between them, as would be expected from distinct species. In the United States, however, hybrids between these forms are ubiquitous. Such hybrids between human-biters and bird-biters may be the bridge vectors contributing to the unprecedented severity and range of the West Nile virus epidemic in North America.
Science. 2004 Mar 5;303(5663):1535-8.
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作者:admin@医学,生命科学 2011-04-02 05:11
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