由买买提看人间百态

boards

本页内容为未名空间相应帖子的节选和存档,一周内的贴子最多显示50字,超过一周显示500字 访问原贴
Military版 - Economist: The virus may have been born in South-East Asia
相关主题
Is This The Man Behind The Global Coronavirus Pandemic?NBA赛季suspended
WSJ雄文:生物的世纪福布斯:只有中国和韩国模式才能搞定新冠
Panic and Pandemic of COVID-19 UNFOUNDED火锅大王这个视频还是比较客观的
Coronavirus - ten reasons not to panic还是可以空气传播
外国千老的详细综述参议院情报委员会长早在2月27号就在私下警告过病毒的厉害
lubbock用一个本科生google来的东西为病毒所辩护过程说明美国人民今天才第一次听说有能抗新冠病毒的药物
华人聚集区要完蛋了, CDC 要 close 你们的学校公司今年真正赚钱的时机已经过了???!!! (转载)
Bill Gates: Coronavirus may be ‘once-in-a-century pathogen we’ve been worried about’美国关于冠状病毒情报的惊人崩溃
相关话题的讨论汇总
话题: china话题: sars话题: bats话题: east话题: south
进入Military版参与讨论
1 (共1页)
u***r
发帖数: 4825
1
http://www.economist.com/science-and-technology/2020/07/22/the-hunt-for-the-origins-of-sars-cov-2-will-look-beyond-china
Bat signal
The hunt for the origins of SARS-CoV-2 will look beyond China
The virus may have been born in South-East Asia
Editor’s note: Some of our covid-19 coverage is free for readers of The
Economist Today, our daily newsletter. For more stories and our pandemic
tracker, see our hub
One of the great questions of the past six months is where sars-cov-2, the
virus that causes covid-19, came from. It is thought the answer involves
bats, because they harbour a variety of sars-like viruses. Yunnan, one of
China’s southernmost provinces, has drawn the attention of virus hunters,
as the closest-known relatives of sars-cov-2 are found there. But some think
the origins of the virus are not to be found in China at all, but rather
just across the border in Myanmar, Laos or Vietnam.
This is the hunch of Peter Daszak, head of EcoHealth Alliance, an
organisation which researches animals that harbour diseases that move into
people. Since the outbreak, in 2003, of the original sars (now known as sars
-cov), scientists have paid close attention to coronaviruses. Dr Daszak says
that around 16,000 bats have been sampled and around 100 new sars-like
viruses discovered. In particular, some bats found in China are now known to
harbour coronaviruses that seem pre-adapted to infect people. The
chiropteran hosts of these viruses have versions of a protein called ace2
that closely resemble the equivalent in people. This molecule is used by
sars-like viruses as a point of entry into a cell.
That such virological diversity has so far been found only in China is
because few people have looked at bats in countries on the other side of the
border. Yet these places are likely to be an evolutionary hotspot for
coronaviruses—one that mirrors bat diversity (see map). The horseshoe bats
in Yunnan which harbour close relatives of sars-cov-2 are found across the
region. Other countries are thus likely to have bats with similar viral
building blocks. Dr Daszak believes it is “quite likely that bats in
Myanmar, Laos and Vietnam carry similar sars-related coronaviruses, maybe a
huge diversity of them, and that some of them could be close to sars-cov-2”.
None of this, though, explains how a virus whose ancestor may be found in
South-East Asian bats went on to start a pandemic from central China. China
’s government has agreed that a mission led by the World Health
Organisation (who) can visit later this year to help answer this question.
There is particular interest in how much sampling has been conducted to look
for the missing link in places like the wildlife market in Wuhan (the first
known centre of the outbreak) and more generally in farmers, traders and
possible intermediate or host species.
Jeremy Farrar, the head of the Wellcome Trust, a large medical-research
charity, and a former professor of tropical medicine, says his guess is that
either sars-cov-2 or something similar to it has been circulating in people
in parts of South-East Asia and southern China, probably for many years,
and that intermediate hosts have not yet been identified. Dr Farrar spent 18
years working in Vietnam as the head of an Oxford University research unit.
He says people go searching for bats for food and sell them in markets in
what is a sophisticated trade that can end up in big cities like Wuhan. Bats
are able to carry a huge diversity of viruses without getting sick, and are
also more mobile than people realise. As he puts it, bats “congregate in
huge colonies, and poo everywhere. And then other mammals live off that poo
and then act as a mixing vessel for these sorts of viruses.”
Support for the idea that something resembling sars-cov-2 might have been
circulating in the region before the pandemic began also comes from another
intriguing observation: the low incidence of covid-19 in South-East Asia,
particularly in Vietnam. John Bell, a professor of medicine at the
University of Oxford, says everyone thought there would be a flood of cases
in Vietnam because the country is right across the border from China. Yet
Vietnam has reported only 300 in a population of 100m, and no deaths. The
country did not have a great lockdown either, he adds. Nobody could work out
what was going on.
One explanation, he suggests, is that Vietnam’s population is not as
immunologically “naive” as has been assumed. The circulation of other sars
-like viruses could have conferred a generalised immunity to such pathogens.
So, if a new one emerged in the region, it was able to take hold in the
human population only when it travelled all the way to central China—where
people did not have this natural resistance.
This would tie in with the idea that infection with one coronavirus can
provide protection against others, and that even in countries away from the
evolutionary cauldron of South-East Asia part of the population may have
some protection against the current pandemic. In particular, there are
suggestions that protection might be conferred mainly via part of the immune
system called t-cells (which work by killing virus-infected cells) rather
than via antibodies (which work by gumming up pathogens). If that is the
case, then serological studies which look at antibodies may be
underestimating natural immunity.
Sunetra Gupta, an epidemiologist at Oxford, argues that natural immunity to
covid-19 is conferred by infections with seasonal coronaviruses. If correct,
this has implications for the level of vaccination needed to reach herd
immunity. It is widely assumed that over 50% of people need to be vaccinated
to prevent a resurgence of sars-cov-2. In a preprint released on July 15th
Dr Gupta says this figure could be much lower if a significant part of the
population is already resistant to infection.
As for the mystery of the origin of covid-19, more answers will come when
the who mission takes place, perhaps in August. The critical steps that led
a South-East Asian bat virus to start a pandemic could have happened inside
or outside of China—whether in wild-animal markets or farms, or in traders
or hunters. The virus may have jumped directly from bats into people, or
come via an intermediate species. The story is waiting to be told. ■
Editor’s note: Some of our covid-19 coverage is free for readers of The
Economist Today, our daily newsletter. For more stories and our pandemic
tracker, see our hub
u***r
发帖数: 4825
u***r
发帖数: 4825
a*****V
发帖数: 1
4
越南民主化,供应链外移,是不会逆转的. 土鳖国不愿意成仁可以自焚嘛. 发这鸟文有个
屁用.//
a*****V
发帖数: 1
5
不发骗人的逼交诱势,整这个狗拿耗子的大杂烩,<<鸡鸡穴人>>拿了土鳖的多少淫渍?
m***y
发帖数: 14763
6
老牌帝国主义真不是盖的,一下子就HOLD住了全场气氛。
大家都松了口气,盯住了越猴。
越猴感到了领导们的重视,骨头都轻了三斤
E*******F
发帖数: 2165
7
越南柬埔寨这些医疗条件差,死人却很少
大概早就跟蝙蝠协同进化了
k****r
发帖数: 421
8
给美国洗地来了吧。。。。。
j****z
发帖数: 299
9
嗯,继续挖,还能挖出更多细节
b*********4
发帖数: 1
10


【在 m***y 的大作中提到】
: 老牌帝国主义真不是盖的,一下子就HOLD住了全场气氛。
: 大家都松了口气,盯住了越猴。
: 越猴感到了领导们的重视,骨头都轻了三斤

o*******t
发帖数: 1
11
我日,还有越舔这么下贱的老将
中国现在把生产线送给越猴,帮他们调试安装好,他们都run不起来,没电
越猴那基建,你以为台巴子用爱发电的技术传授给越猴了?
越猴现实的态度就是接受一些中国淘汰的劳动密集型,污染密集型产业
挣点钱买中国的工业产品,成为中华经济圈的外围成员,这是现实的
你让他们买欧美高价货,他们买不起啊
越猴想发展经济,必须努力维护和平的环境,敢得罪中国这个环境就不存在了

【在 a*****V 的大作中提到】
: 越南民主化,供应链外移,是不会逆转的. 土鳖国不愿意成仁可以自焚嘛. 发这鸟文有个
: 屁用.//

j****z
发帖数: 299
12
迹象越来越显示中国是受害人呀,好在中国基本控制住了,要不然14亿人口,想想都可
1 (共1页)
进入Military版参与讨论
相关主题
老将喜讯:波音向所有员工提供自愿被解雇的机会ZT reuters外国千老的详细综述
为防疫 FDA放宽对同性恋献血要求lubbock用一个本科生google来的东西为病毒所辩护过程说明
COVID-19 PANIC: Masks Will Worsen the Problem华人聚集区要完蛋了, CDC 要 close 你们的学校公司
白宫医生承认:中国没有报告 how contagious coronavirus wasBill Gates: Coronavirus may be ‘once-in-a-century pathogen we’ve been worried about’
Is This The Man Behind The Global Coronavirus Pandemic?NBA赛季suspended
WSJ雄文:生物的世纪福布斯:只有中国和韩国模式才能搞定新冠
Panic and Pandemic of COVID-19 UNFOUNDED火锅大王这个视频还是比较客观的
Coronavirus - ten reasons not to panic还是可以空气传播
相关话题的讨论汇总
话题: china话题: sars话题: bats话题: east话题: south