首页
登录
职称英语
Wild ducks and other migratory (迁移的) birds could be important carriers of dea
Wild ducks and other migratory (迁移的) birds could be important carriers of dea
游客
2023-09-09
71
管理
问题
Wild ducks and other migratory (迁移的) birds could be important carriers of deadly bird flu, researchers say. Even so, the infectious-disease experts say there is no solid basis for killing wild birds to protect poultry and minimize the risk of human infection.
The European team investigating the global spread of the H5N1 strain of avian influenza (禽流感) says certain duck species may be infecting wild bird populations. Geese and wading birds are also possible vectors (带菌者) of the virus, the team says.
The team’s study was led by Bjorn Olseo of Umea University in Sweden. Olsan runs Europe’s largest wild-bird flu monitoring program.
Studies have shown that influenza viruses in lake water, generally passed via bird feces(粪), can stay infectious for up to 30 days. The migration or feeding behavior of dabbling ducks could at least partially explain the spread of the H5N1 strain of bird flu, the researchers add.
This group of duck species includes mallards, teal, pintails, and others that feed at or near the surface, where viruses in water are most likely to be picked up. Perhaps as a result, dabblers have the highest known rates of avian influenza infection, the study says. For instance, nearly 13 percent of mallards tested positive for bird flu. Other species tested include the American black duck (18.1 percent), blue-winged teal (11.5 percent ), and northern pintail (11.2 percent).
However, bird flu viruses appear to exist in ducks in a low-pathogenic form, meaning infection doesn’t usually lead to severe illness and death.
"Dabbling ducks are for sure the prime hosts for low pathogenic viruses," said study co-author Ron Fouchier, a virologist at the Erasmus Medical Center in Rotterdam, Netherlands. "But the big question is, how much of our knowledge about these viruses can we translate to high-pathogenic viruses such as the H5N1 strain of bird flu?"
In poultry avian viruses can mutate(变异) into more virulent influenza strains, including H5N1. If this mutated virus then finds its way back into wild populations, the birds could then spread the disease through migration.
Some scientists have argued that wild birds infected with HN51 would be too ill to migrate. Swans, for instance, appear to be particularly vulnerable to the strain. "Swans apparently drop dead quite easily, but they are unlikely to be the vector because they are not going to fly very far if they are dead," Fouchier said.
But the study team says that some birds that have been purposely infected for the sake of research show that wild birds can survive H5NI. "For some reason H5N1 has adapted so it no longer kills dabbling ducks," Fouchier said. This means the ducks may be able to spread the virus over a wide area.
The study team says migratory geese may also be vectors, because they olden graze in huge flocks, a practice that could encourage transmission.
Migrating ducks, the researchers add, "could provide an intercontinental bridge" for bird flu to North America, which has not yet had any known cases of H5N1. [br] According to the study team, ______ is a practice that can encourage transmission of the bird flu.
选项
答案
grazing in huge flocks
解析
根据题干中的关键词study team和encourage transmission定位到倒数第二段,可知研究组表示,迁徙的鹅可能也是病毒携带者,因为它们经常聚在一起吃草,而这可能会促使病毒的传播。
转载请注明原文地址:https://tihaiku.com/zcyy/2999300.html
相关试题推荐
Theroleofthefarmerhasalwaysbeenanimportantone.Twohundredyearsa
Theroleofthefarmerhasalwaysbeenanimportantone.Twohundredyearsa
Theroleofthefarmerhasalwaysbeenanimportantone.Twohundredyearsa
Theroleofthefarmerhasalwaysbeenanimportantone.Twohundredyearsa
Theroleofthefarmerhasalwaysbeenanimportantone.Twohundredyearsa
______(知道如何充分利用你的才能)ismuchmoreimportantthanworkinghard.Knowinghowtom
[originaltext]Atonetimeitwasthemostimportantcityintheregion--ab
[originaltext]Atonetimeitwasthemostimportantcityintheregion--ab
Themostimportantstepindevelopinganeffectivecampaign,andthestepwh
[originaltext]Yogabecomesverypopularnowadays,butitisimportantthat
随机试题
尽管中国耕地面积有限,但已解决了吃住问题。然而,过多使用化肥导致农田效率低下和严重的污染。北方地区化肥的使用量超出庄稼需要量的40%。中国的粮食产量占世
Withtheflowers______everywhere,theparklooksbeautiful.A、tobloomB、blooming
Weallhopethatthevaluesthatareimportanttoeachofusarepassedalon
关于“六部”,说法正确的有( )。A.六部制始于隋唐 B.武官的选用归吏部掌
进行通风气流组织设计时,应遵循的原则是()。A.将新鲜空气送到作业地带或操作
证券公司、证券投资咨询机构应当向客户提供风险揭示书,并由客户签收确认。《风险揭示
下列有关商誉的表述中,正确的是:A:商誉应定期摊销计入损益 B:商誉产生于非同
某市统计局在针对噪音扰民的一次调查中,当问及受访市民对哪一类噪音反感时,选择社区
1,2,2,4,2,8,4,16,()。 A.16 B.10 C.6 D
某承包商在混凝土重力坝施工过程中,采用分缝分块常规混凝土浇筑方法。由于工期紧,浇
最新回复
(
0
)