考博英语作文题 npj5U/
^ 0eO\wc?O
题目:Bird flu and the deteriorating environment Nh :4ys!P
范文 l hg&u0AQ2
Earlier this year, bird flu panic was in full swing: The French hU+#S(t>b
feared for their foie gras, the Swiss locked their chickens indoors, `skH-lk,
and Americans enlisted prison inmates in Alaska to help spot |VYr=hj o
infected wild birds. 'A1E^rl]=
k!
vHO
The H5N1 virus - previously confined to Southeast Asia - was >vxWx[fRu
striking birds in places as diverse as Germany, Egypt, and Nigeria, 7YD\ !2b
and a flu pandemic seemed inevitable. v C-[#]<
C\/b~HU
Then the virus went quiet. Except for a steady stream of human cases 8_Jj +
in Indonesia, the current flu epicenter, the past year's worries F]0Jwm{
about a catastrophic global outbreak largely disappeared. =x oBC&u
What happened?
u{pTva
qs " s/$
Part of the explanation may be seasonal. Bird flu tends to be most 5@iy3olP
active in the colder months, as the virus survives longer at low V"BVvSNu
temperatures. +O,V6XRr
[e1\ A
&T
"Many of us are holding our breath to see what happens in the qjzZ}
winter," said Dr. Malik Peiris, a microbiology professor at Hong y^, "gD
Kong University. "H5N1 spread very rapidly last year," Peiris said. [ (!Q- 8
"So the question is, was that a one-off incident?" @_(nd57oSs
Vj29L?3
Some experts suspect poultry vaccination has, paradoxically, M Ey1~h/
complicated detection. Vaccination reduces the amount of virus "3v7 gtGG
circulating, but low levels of the virus may still be causing pDP3 3`OFh
outbreaks - without the obvious signs of dying birds. ^sJ1 ^LT
FV`3,NFk
"It's now harder to spot what's happening with the flu in animals
I8:"h
and humans," said Dr. Angus Nicoll, influenza director at the $B*qNYpPy.
European Centres for Disease Control and Prevention. ER/\ +Z#Z
0H; "5
While the pandemic has not materialized, experts say it's too early 9]"\"ka3>
to relax. twAw01".
"MW55OWYU
"We have a visible risk in front of us," said Dr. Keiji Fukuda, UzXDi#Ky
coordinator of the World Health Organization's global influenza _P>1`IR
program. But although the virus could mutate into a pandemic strain, 5/* )+
Fukuda points out that it might go the other direction instead, #d3[uF]OmW
becoming less dangerous for humans. B[C7G7 <B
:/ ~):tM
H5N1 has primarily stalked Asia. This year, however, it crossed the (M4]#5
continental divide, infecting people in Turkey, Iraq, Egypt, =B 1`R %t
Djibouti, and Azerbaijan. ^!N;F"
7MR:X#2v>
But despite the deaths of 154 people, and hundreds of millions of Z#H@BWN7
birds worldwide dying or being slaughtered, the virus still has not BF@m )w.v
learned how to infect humans easily. [I#Q
f J,8g/f8
Flu viruses constantly evolve, so the mere appearance of mutations 0]f?Dx/8
is not enough to raise alarm. The key is to identify which mutations Rt*-#`I
$
are the most worrisome. E;ndw/GZjR
J$o[$G_Z
"We don't really know how many changes this virus has got to make to RXIH(WiK
adapt to humans, if it can at all," said Dr. Richard Webby, a bird &e5^v
flu expert at St. Jude Children's Research Hospital in Tennessee. n:%'{}Jw
Zb5T90s%
The most obvious sign that a pandemic may be under way will almost -K{\S2
certainly come from the field: a sudden spike in cases suggesting i[ V,IP +
human-to-human transmission. The last pandemic struck in 1968 - when +9& ulr
bird flu combined with a human strain and went on to kill 1 million F!DrZd>\
people worldwide. B$iMU?B3
~c WLu5
In May, on Sumatra island in Indonesia, a cluster of eight cases was ~ 8S4Kj)%
identified, six of whom died. The World Health Organization @DjG? yLK$
immediately dispatched a team to investigate. !YuO
N6{)
The U.N. agency was concerned enough by the reports to put 2l;ge>D J
pharmaceuticals company Roche Holding AG on standby in case its I+-Rs2wb
global antiviral stockpile, promised to WHO for any operation to vErbX3RY2
quash an emerging pandemic, needed to be rushed to Indonesia. {ILQ
CvP*
cfF-e93T
Luckily, the Sumatra cluster was confined to a single family. Though pD)/- Dgdm
human-to-human transmission occurred - as it has in a handful of M\x7=*\
other cases - the virus did not adapt enough to become easily `jl. f
infectious. $ET/0v"V
,&
{5,=
This highlighted many of the problems that continue to plague public dh 7)N}2
health officials, namely, patchy surveillance systems and limited KH CdO
virus information. IT {.^ rP
<CdG[Ih
Even in China, where H5N1 has circulated the longest, surveillance FkkZyCqZ`
is not ideal. xHR+((
:D )&>{?
"Monitoring the 14 billion birds in China, especially when most of N*c?Er@8U
them are in back yards, is an enormous challenge," said Dr. Henk ~`Gcq"7, !
Bekedam, WHO's top official in China. Of the 21 human cases China J0Rz. =Y
has logged so far, 20 were in areas without reported H5N1 outbreaks 67hPQ/S1
in birds. k}owEBsn}
c&iK+qvh{
"We need to start looking harder for where the virus is hiding," Tef3
Z6
Bekedam said. "=0 lcb C
r 5 $?4t
To better understand the virus' activity, it would help to have more QK/+*hr;
virus samples from every H5N1-affected country. But public health (Os
OPT
p
authorities are at the mercy of governments and academics. @XSu?+s)
Scientists may hoard viruses while waiting for academic papers to be hSf#;=9'
published first. And developing countries may be wary of sharing PX>\ j&
virus samples if the vaccines that might be developed from them 3[g++B."pC
might ultimately be unaffordable. 28L'7
D_;n4<|.
That leaves public health officials with an incomplete viral )* AA9
picture. I4DlEX
.}u(&
"It shouldn't just be WHO as a lonely voice in the desert, calling %}AY0fg?T
for more viruses (to be shared)," said Dr. Jeff Gilbert, a bird flu ~{tZ
;YZ
expert with the Food and Agriculture Organization in Vietnam. All NCh(-E
countries, need to understand that sharing will help them better *'S%gR=Aa+
prepare for a flu pandemic, he said. x @R A1&c
E ;F top
Though scientists are bracing themselves for increased bird flu
;
.
[$
activity in the winter, there are no predictions about where it wjGjVTt
Hs
might appear next. The WHO's Fukuda said it would not be a surprise #?d#s19s
to see it appear in new countries.
