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题目:Bird flu and the deteriorating environment x|@1 wQ" 6
范文 l ]aC ':55(
Earlier this year, bird flu panic was in full swing: The French (s}Rj)V[^
feared for their foie gras, the Swiss locked their chickens indoors, =vq s d4
and Americans enlisted prison inmates in Alaska to help spot +cz"`T`X 2
infected wild birds. pqyWv;
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The H5N1 virus - previously confined to Southeast Asia - was 3]O`[P,*%
striking birds in places as diverse as Germany, Egypt, and Nigeria, P0%N
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and a flu pandemic seemed inevitable. ?^%YRB&
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Then the virus went quiet. Except for a steady stream of human cases 6 gj]y ^}
in Indonesia, the current flu epicenter, the past year's worries :/o C:z\h
about a catastrophic global outbreak largely disappeared. z.eJEK
What happened? 2y3?!^$
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Part of the explanation may be seasonal. Bird flu tends to be most 9#v-2QY
active in the colder months, as the virus survives longer at low h&)fu{
temperatures. v6wRME;JA
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"Many of us are holding our breath to see what happens in the Yo >`h2C4
winter," said Dr. Malik Peiris, a microbiology professor at Hong 4bP13f
Kong University. "H5N1 spread very rapidly last year," Peiris said. 8';m)Jc
"So the question is, was that a one-off incident?" ,"~WkLI~\t
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Some experts suspect poultry vaccination has, paradoxically,
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complicated detection. Vaccination reduces the amount of virus q _cC7p6t
circulating, but low levels of the virus may still be causing }1 $h xfb
outbreaks - without the obvious signs of dying birds. cppL0myJ
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"It's now harder to spot what's happening with the flu in animals `,+#! )
and humans," said Dr. Angus Nicoll, influenza director at the !_qskDc-
European Centres for Disease Control and Prevention. :* ^ :T_U
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While the pandemic has not materialized, experts say it's too early M|d={o9Hp
to relax. (B@X[~
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"We have a visible risk in front of us," said Dr. Keiji Fukuda, 1n_; kaY
coordinator of the World Health Organization's global influenza cgyp5\*>+
program. But although the virus could mutate into a pandemic strain, 5UE409Gn'
Fukuda points out that it might go the other direction instead, yf!,4SUkU
becoming less dangerous for humans. nTPB,QE<
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H5N1 has primarily stalked Asia. This year, however, it crossed the cph~4wCS[U
continental divide, infecting people in Turkey, Iraq, Egypt, 5k]XQxc6_
Djibouti, and Azerbaijan. %`e`g ^
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But despite the deaths of 154 people, and hundreds of millions of s.VA!@F5
birds worldwide dying or being slaughtered, the virus still has not r$ =qQ7^#
learned how to infect humans easily. ) V36t{
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Flu viruses constantly evolve, so the mere appearance of mutations Ql8bt77eI-
is not enough to raise alarm. The key is to identify which mutations fxd0e;NAAh
are the most worrisome. k^%2_
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"We don't really know how many changes this virus has got to make to zPR8f-U vw
adapt to humans, if it can at all," said Dr. Richard Webby, a bird X P;Bhz3j
flu expert at St. Jude Children's Research Hospital in Tennessee. g\Ak;03n
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The most obvious sign that a pandemic may be under way will almost $e
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certainly come from the field: a sudden spike in cases suggesting y S!(A p
human-to-human transmission. The last pandemic struck in 1968 - when oZN'H T
bird flu combined with a human strain and went on to kill 1 million 'N\&<dT>
people worldwide. NLyXBV[hV
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In May, on Sumatra island in Indonesia, a cluster of eight cases was l+[czb~
identified, six of whom died. The World Health Organization ]a?bzO r,
immediately dispatched a team to investigate. j+kC-U;
The U.N. agency was concerned enough by the reports to put iidT~l
pharmaceuticals company Roche Holding AG on standby in case its D z;HAyPj
global antiviral stockpile, promised to WHO for any operation to mrM4RoO
quash an emerging pandemic, needed to be rushed to Indonesia. ab.tH$:<
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Luckily, the Sumatra cluster was confined to a single family. Though z wk.bf>m
human-to-human transmission occurred - as it has in a handful of =-#G8L%Q
other cases - the virus did not adapt enough to become easily g`0mo Xz
infectious. Fky?\ec
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This highlighted many of the problems that continue to plague public !L$x:/R9M
health officials, namely, patchy surveillance systems and limited )C~9E 5E
virus information. A m"(+>W21
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Even in China, where H5N1 has circulated the longest, surveillance 2g-` ]Vqb
is not ideal. /7"I#U^u/
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"Monitoring the 14 billion birds in China, especially when most of #7G*GbKY
them are in back yards, is an enormous challenge," said Dr. Henk zt ll}
Bekedam, WHO's top official in China. Of the 21 human cases China & ,: h)
has logged so far, 20 were in areas without reported H5N1 outbreaks uLR<FpM
in birds. zM#sOg
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"We need to start looking harder for where the virus is hiding," = =N{1gO]
Bekedam said. lLhL`C !
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To better understand the virus' activity, it would help to have more dT|vYK}\
virus samples from every H5N1-affected country. But public health 3uWkc3
authorities are at the mercy of governments and academics. 49H+(*@v@
Scientists may hoard viruses while waiting for academic papers to be #W>QY Tp
published first. And developing countries may be wary of sharing (V:E2WR
virus samples if the vaccines that might be developed from them b aV>N[F&
might ultimately be unaffordable. ]6r;}1c
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That leaves public health officials with an incomplete viral ').}N z
picture. q? qC
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"It shouldn't just be WHO as a lonely voice in the desert, calling 9;.(u'y|
for more viruses (to be shared)," said Dr. Jeff Gilbert, a bird flu l
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expert with the Food and Agriculture Organization in Vietnam. All <EO$]>;0
countries, need to understand that sharing will help them better <7SpEVQ
prepare for a flu pandemic, he said. Fb22p6r
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Though scientists are bracing themselves for increased bird flu H %J
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activity in the winter, there are no predictions about where it i 9<pqQ
might appear next. The WHO's Fukuda said it would not be a surprise q;g>t5]a
to see it appear in new countries.
