首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Wild ducks and other migratory (迁移的) birds could be important carriers of deadly bird flu, researchers say. Even so, the infecti
Wild ducks and other migratory (迁移的) birds could be important carriers of deadly bird flu, researchers say. Even so, the infecti
admin
2010-09-25
41
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.
According to the author, what may be the possible carriers of bird flu?
选项
答案
Wild ducks and other migratory birds. /Ducks,geese and wading birds.
解析
文章开头指出,野鸭以及其他迁徙鸟类可能是致命性禽流感的重要携带者,由此可得答案;第二段又提到,鸭子可能在传染野鸟,而鹅和涉水鸟也可能是病毒的携带者,由此也可得答案。
转载请注明原文地址:https://kaotiyun.com/show/vWz7777K
0
大学英语六级
相关试题推荐
Educationisoneofthekeywordsofourtime.Amanwithoutaneducation,manyofusbelieve,isanunfortunatevictimofadver
BythetimeyougettoNewYork,I______(已经动身去)London.
Amongits1.8millionresidents,thereisonanaverageoneAsian______(每4个居民中).
A、Unemployment.B、Familybreak-up.C、Mentalproblem.D、Drinking.B
Theimplicationseemstobethat_________________________(不可能在进行经济改革的同时实现民主).
A、1:50.B、1:55.C、2:00.D、2:05.A综合推断题。男士问快车是否是2:05开车,女士回答说是1:55开,还差五分钟了,由此可知,现在是1:50。
Thatlady*toldmeittook______(步行不到五分钟就可到达附近的公共汽车站).
Thereisnodoubtthat______(我们的教育体系令人不满意).
A、Hisheadache.B、Hissmoking.C、Hisgirlfriend.D、Hissister.D主旨大意题[考频:2]。女士询问男士情绪反常的原因,男士明确回答女人的麻烦事是最令人头疼的,后文也具体讲述他和女友之间发生的矛
随机试题
学前教育有托儿所及幼儿园,小学之后有中学及大学,并且在各级学校之间形成一种有序的组织。这主要体现了现代学校教育所具有的特征是()。
糖尿病肾病最早出现的临床表现,也是筛选早期糖尿病肾病的主要指标是()
A.交感神经B.副交感神经C.运动神经D.传入神经E.传出神经当动物遇到各种紧急情况时,()系统的活动明显增强
第5胸椎棘突下旁开1.5寸的腧穴是第3胸椎棘突下旁升1.5寸的腧穴是
多巴胺的作用为( )。
【背景资料】某工贸集团决定新建一机械制造厂,通过招标方式与市建工集团安装公司签订了工程施工合同。因该安装公司没有能力完成土建工程施工,经业主同意,将基础工程、屋面工程和装修工程分包给了市建工集团星鼎公司。开工日期为2011年5月18日,合同工期67天。施
银行间债券市场上回购业务的类型包括()。Ⅰ.质押式回购业务Ⅱ.买断式回购业务Ⅲ.开放式回购业务Ⅳ.抵押式回购业务
下列各项中,不属于事业部制组织结构优点的有()。
我国重要的主体公园包括()。
求
最新回复
(
0
)