考博英语作文题 S8Fmy1#
YZ$ZcfXDW
题目:Bird flu and the deteriorating environment 0
H_!Kg
范文 l kUx&pYv
Earlier this year, bird flu panic was in full swing: The French Q:C$&-$
feared for their foie gras, the Swiss locked their chickens indoors, 9Mp$8-=>7
and Americans enlisted prison inmates in Alaska to help spot Q e"pW\
infected wild birds. gwd (N
j V gFZ,
The H5N1 virus - previously confined to Southeast Asia - was ,B<l
striking birds in places as diverse as Germany, Egypt, and Nigeria, q@5K6yE
and a flu pandemic seemed inevitable. HBE.F&C88
h_d +$W5
Then the virus went quiet. Except for a steady stream of human cases V
==z"
in Indonesia, the current flu epicenter, the past year's worries spofLu.
about a catastrophic global outbreak largely disappeared. l%R50aL
What happened? DD9 ?V}Yx
Q^K "8 ;
Part of the explanation may be seasonal. Bird flu tends to be most <m MTD8Sx]
active in the colder months, as the virus survives longer at low ,fIe&zq
temperatures. OU4pjiLx
7`IpBm<
"Many of us are holding our breath to see what happens in the Z|9u]xL
winter," said Dr. Malik Peiris, a microbiology professor at Hong
8@{OR"Ec
Kong University. "H5N1 spread very rapidly last year," Peiris said. vzel#
"So the question is, was that a one-off incident?" ;|p$\26S)%
S
_T^G` [
Some experts suspect poultry vaccination has, paradoxically, [a o
U5;7
complicated detection. Vaccination reduces the amount of virus >R{qESmP=
circulating, but low levels of the virus may still be causing qa(>wR"mT
outbreaks - without the obvious signs of dying birds. %S`
v!*2
rKHY? {!
"It's now harder to spot what's happening with the flu in animals H+}"q$
and humans," said Dr. Angus Nicoll, influenza director at the G'zF)0oD
European Centres for Disease Control and Prevention. n 26Y]7N
g>d;|sK
While the pandemic has not materialized, experts say it's too early 22<0DhJ
to relax. ^[Ua46/" m
< _$%@4 L
"We have a visible risk in front of us," said Dr. Keiji Fukuda, B()/.w?A
coordinator of the World Health Organization's global influenza YI-O{U
program. But although the virus could mutate into a pandemic strain, rV({4cIe9R
Fukuda points out that it might go the other direction instead, "x941 }
becoming less dangerous for humans. IC{e E
[ >#*B9
H5N1 has primarily stalked Asia. This year, however, it crossed the LAx4Xp/
continental divide, infecting people in Turkey, Iraq, Egypt, J`IDlGFYp
Djibouti, and Azerbaijan. zL5d0_E9
/sR%]q
|L
But despite the deaths of 154 people, and hundreds of millions of E$a ?LFa6
birds worldwide dying or being slaughtered, the virus still has not Tj~ I aU
learned how to infect humans easily. /2{5;
I9o6k?$K
Flu viruses constantly evolve, so the mere appearance of mutations nFX_+4V2
is not enough to raise alarm. The key is to identify which mutations EA.D}X C
are the most worrisome. 30PZ{c&Rll
H7+X&#s%
"We don't really know how many changes this virus has got to make to RWgDD;&_[a
adapt to humans, if it can at all," said Dr. Richard Webby, a bird %pu Lr'Y
flu expert at St. Jude Children's Research Hospital in Tennessee. ,1q_pep~?%
GN#<
yv$av
The most obvious sign that a pandemic may be under way will almost Q@e[5RA +]
certainly come from the field: a sudden spike in cases suggesting O_$d I*RK
human-to-human transmission. The last pandemic struck in 1968 - when d;Hn#2C
bird flu combined with a human strain and went on to kill 1 million %xwIt~
Y
people worldwide. K.C>
a:J
2LCB])X
In May, on Sumatra island in Indonesia, a cluster of eight cases was C\_zdADUb%
identified, six of whom died. The World Health Organization /w
QL
immediately dispatched a team to investigate. U,/6;}
The U.N. agency was concerned enough by the reports to put y#Ht{)C
pharmaceuticals company Roche Holding AG on standby in case its 6{x,*[v
global antiviral stockpile, promised to WHO for any operation to Xf =XBoN|
quash an emerging pandemic, needed to be rushed to Indonesia. IM=bK U
F Kc; W
Luckily, the Sumatra cluster was confined to a single family. Though k<w(i
k1bi
human-to-human transmission occurred - as it has in a handful of Jxf~&!zR
other cases - the virus did not adapt enough to become easily Bhp OXqg
infectious. I~PDaZP
O <9~Kgd8h
This highlighted many of the problems that continue to plague public d
"BW/%m|g
health officials, namely, patchy surveillance systems and limited r#WT`pav
virus information. a\kb^D=T
2^~<("+ w
Even in China, where H5N1 has circulated the longest, surveillance HDM<w+ZxX
is not ideal. '"pd
+y[@ T6_
"Monitoring the 14 billion birds in China, especially when most of | sqZ $M u
them are in back yards, is an enormous challenge," said Dr. Henk di9!lS $
Bekedam, WHO's top official in China. Of the 21 human cases China > 1L=,M
has logged so far, 20 were in areas without reported H5N1 outbreaks /4=-b_2Y~
in birds. ;y?) ;!g
2J;`m_oP
"We need to start looking harder for where the virus is hiding," ydl jw
Bekedam said. BOlAm*tFt
U IJx*
To better understand the virus' activity, it would help to have more VCNT4m
virus samples from every H5N1-affected country. But public health gLD`wfZR
authorities are at the mercy of governments and academics. r'/;O
Scientists may hoard viruses while waiting for academic papers to be @z6!a
published first. And developing countries may be wary of sharing 'iSAAwT2aj
virus samples if the vaccines that might be developed from them 4z7G2
might ultimately be unaffordable. Ftb%{[0}u3
,cTgR78'
That leaves public health officials with an incomplete viral }6RT,O g
picture. x c
1A$EY
UyYfpL"$A"
"It shouldn't just be WHO as a lonely voice in the desert, calling H { M)-
for more viruses (to be shared)," said Dr. Jeff Gilbert, a bird flu 9pWy"h$H
expert with the Food and Agriculture Organization in Vietnam. All dLh6:Gh8_I
countries, need to understand that sharing will help them better A(6xg)_XQ
prepare for a flu pandemic, he said. -
Q
e~)7
Y8s;w!/
Though scientists are bracing themselves for increased bird flu A//?6O Jx?
activity in the winter, there are no predictions about where it mxTk+j=
might appear next. The WHO's Fukuda said it would not be a surprise >X}{BDMb.
to see it appear in new countries.
