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题目:Bird flu and the deteriorating environment \uo{I~Qd
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Earlier this year, bird flu panic was in full swing: The French s4f{ziLp
feared for their foie gras, the Swiss locked their chickens indoors, #t Pc<p6m
and Americans enlisted prison inmates in Alaska to help spot 0RSzDgX
infected wild birds. e+#k\x
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The H5N1 virus - previously confined to Southeast Asia - was W 4P\H M>2
striking birds in places as diverse as Germany, Egypt, and Nigeria, /9SoVU8
and a flu pandemic seemed inevitable. 7$0 bgWi
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Then the virus went quiet. Except for a steady stream of human cases VS`{k^^
in Indonesia, the current flu epicenter, the past year's worries S 1~EJa5H
about a catastrophic global outbreak largely disappeared. 'Zex/:QS
What happened? M.qv'zV`xG
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Part of the explanation may be seasonal. Bird flu tends to be most Wzff p}V
active in the colder months, as the virus survives longer at low i;qij[W. z
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"Many of us are holding our breath to see what happens in the F4V) 0)G
winter," said Dr. Malik Peiris, a microbiology professor at Hong M= 3 w
Kong University. "H5N1 spread very rapidly last year," Peiris said. vq3:N'
"So the question is, was that a one-off incident?" h'vBWtMa
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Some experts suspect poultry vaccination has, paradoxically, [T [] U
complicated detection. Vaccination reduces the amount of virus F_/ra?W VH
circulating, but low levels of the virus may still be causing eQ[}ALIq
outbreaks - without the obvious signs of dying birds. 5w~J"P6jg
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"It's now harder to spot what's happening with the flu in animals +l]> (k.2
and humans," said Dr. Angus Nicoll, influenza director at the ?} E
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European Centres for Disease Control and Prevention. #Lk~{
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While the pandemic has not materialized, experts say it's too early qMA";Frt3N
to relax. rY@9nQ\>g
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"We have a visible risk in front of us," said Dr. Keiji Fukuda, S|6i]
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coordinator of the World Health Organization's global influenza VS7
program. But although the virus could mutate into a pandemic strain, (m2_ Eh;
Fukuda points out that it might go the other direction instead, 2o1WXE %$
becoming less dangerous for humans. KCp9P2kv.
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H5N1 has primarily stalked Asia. This year, however, it crossed the Vvfd?G"
continental divide, infecting people in Turkey, Iraq, Egypt, 7.)_H
Djibouti, and Azerbaijan. tt6GtYrC 1
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But despite the deaths of 154 people, and hundreds of millions of ]!jfrj
birds worldwide dying or being slaughtered, the virus still has not 0$=U\[og
learned how to infect humans easily. sK/ymEfRv
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Flu viruses constantly evolve, so the mere appearance of mutations >r}?v3QW
is not enough to raise alarm. The key is to identify which mutations
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are the most worrisome. hl)jE
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"We don't really know how many changes this virus has got to make to ]F;1 l3I-
adapt to humans, if it can at all," said Dr. Richard Webby, a bird v:9'k~4)
flu expert at St. Jude Children's Research Hospital in Tennessee. ~6QV? j
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The most obvious sign that a pandemic may be under way will almost \CS 4aIp
certainly come from the field: a sudden spike in cases suggesting S+^hK1jL
human-to-human transmission. The last pandemic struck in 1968 - when e5; YY
bird flu combined with a human strain and went on to kill 1 million JP^x]t:
people worldwide. 5'w&M{ { 9
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In May, on Sumatra island in Indonesia, a cluster of eight cases was 1g$xKe~]4
identified, six of whom died. The World Health Organization vI48*&]wTf
immediately dispatched a team to investigate. $? [pcgv
The U.N. agency was concerned enough by the reports to put :DuEv:;v
pharmaceuticals company Roche Holding AG on standby in case its
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global antiviral stockpile, promised to WHO for any operation to _oefp*iWS
quash an emerging pandemic, needed to be rushed to Indonesia.
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Luckily, the Sumatra cluster was confined to a single family. Though =n@ \m <
human-to-human transmission occurred - as it has in a handful of i!(5y>I_
other cases - the virus did not adapt enough to become easily 2<'ol65/c
infectious. I,]q;lEMt
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This highlighted many of the problems that continue to plague public t9lf=+%s
health officials, namely, patchy surveillance systems and limited qn}VW0!
virus information. 8R(l~
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Even in China, where H5N1 has circulated the longest, surveillance /h]ru SI
is not ideal. <KoOJMx(
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"Monitoring the 14 billion birds in China, especially when most of A#i[Us|
them are in back yards, is an enormous challenge," said Dr. Henk yi (IIW
Bekedam, WHO's top official in China. Of the 21 human cases China z tp2
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has logged so far, 20 were in areas without reported H5N1 outbreaks 3+iryW(\
in birds. Q0ba;KPm
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"We need to start looking harder for where the virus is hiding," |S:erYE,G
Bekedam said. p&HO~J <w
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To better understand the virus' activity, it would help to have more lWP]}Uy=5~
virus samples from every H5N1-affected country. But public health #v
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authorities are at the mercy of governments and academics. m6 gMVon
Scientists may hoard viruses while waiting for academic papers to be ?pa pk4w
published first. And developing countries may be wary of sharing wuSotbc/
virus samples if the vaccines that might be developed from them ` /B+
might ultimately be unaffordable. }-9 c1&m
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That leaves public health officials with an incomplete viral 2j ]uB0
picture. T&Z*=ShH
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"It shouldn't just be WHO as a lonely voice in the desert, calling &!wtH
for more viruses (to be shared)," said Dr. Jeff Gilbert, a bird flu KUHkj
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expert with the Food and Agriculture Organization in Vietnam. All $
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countries, need to understand that sharing will help them better 3'SN0VL
prepare for a flu pandemic, he said. qT#NS&T!-
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Though scientists are bracing themselves for increased bird flu pP#
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activity in the winter, there are no predictions about where it kD)
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might appear next. The WHO's Fukuda said it would not be a surprise sJ5#T iX
to see it appear in new countries.
