[D66] Chinees CDC: Corona pandemie begon mogelijk bij super-verspreider (Wuhan Coronavirus 2019-nCoV #205)

[Dr. Marc-Alexander Fluks]

Bron:   Business Insider Nederland
Datum:  29 mei 2020
Auteur: Aylin Woodward
URL:    
https://www.businessinsider.nl/coronavirus-did-not-jump-wuhan-market-chinese-cdc-says-2020-5/


The Chinese CDC now says the coronavirus didn't jump to people
at the Wuhan wet market - instead, it was the site of a
super-spreader event
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Experts still don't know where the new  coronavirus came from.

Genetic evidence has all but confirmed that the virus originated in 
Chinese bats before it jumped to humans via an  intermediary animal 
host. But where and how that spillover first happened is still up for 
debate.

Initially, authorities in Wuhan, China, reported that the first cases of 
the virus emerged at the local Huanan Seafood Wholesale Market. But 
following an investigation of the animals sold there, the Chinese 
Centers for Disease Control and Prevention (CDC) said this week that it 
has ruled the site out as the origin point of the outbreak.

According to the  Wall Street Journal, Gao Fu, the director of the 
Chinese CDC, told Chinese state media: 'It now turns out that the market 
is one of the victims.' Samples collected from animals at the market 
came back negative for the new coronavirus, suggesting that they 
couldn't have infected shoppers.


The cases linked to the wet market weren't the first in China

Wuhan authorities first informed the World Health Organization (WHO) 
about the unknown, pneumonialike illness that would later be identified 
as the new coronavirus on December 31.

A majority of the initial 41 cases were linked to the wet market, which 
was shut down on January 1. Given that the SARS outbreak in 2002 and 
2003 started at a similar venue in Guangdong, China, the wet market 
seemed like a logical origin. (The SARS coronavirus jumped from bats to 
civet cats to people.)

But none of the animals at the market tested positive for the virus, 
Colin Carlson, a zoologist at Georgetown University  told Live Science. 
If they were never infected, they couldn't have been the intermediary 
host that facilitated the spillover.

A growing body of research supports the Chinese CDC's conclusion that 
the outbreak's origins were unrelated to the market. The virus seems to 
have been  circulating in Wuhan before those 41 cases were reported: 
Research published in January showed that the first person to test 
positive for the coronavirus was likely exposed to it on December 1, 
then showed symptoms on December 8. The researchers behind the study 
also found that 13 of the 41 original cases showed no link to the wet 
market.

Similarly, an April study suggested that the coronavirus had already 
established itself and begun spreading in the Wuhan community by early 
January.

The identity of 'patient zero' hasn't been confirmed, but it may have 
been a 55-year-old man from China's Hubei province who was infected on 
November 17, according to the South China Morning Post (SCMP), which 
reviewed government documents.


The wet market could have been the site of a super-spreader event

Carlson told Live Science that the Wuhan wet market may simply have been 
the a site of an early  super-spreader event - an instance in which one 
sick person infects an atypically large number of others.

Other super-spreader events around the world have also created clusters 
of infections that cropped up almost overnight. In Daegu, South Korea, 
for example, one churchgoer infected at least 43 people.

These instances don't necessarily involve a person who is more 
contagious than others or sheds more viral particles. Rather, the 
infected person has access to a greater number of people in spaces that 
facilitate infection. A market, in which shoppers interact with one 
another and vendors in close quarters, is one such risky place.


The coronavirus also probably did not leak from a lab

Lingering questions about the pandemic's origin have given rise to a 
range of unsubstantiated theories. One suggests the coronavirus may have 
accidentally leaked from a local laboratory, the Wuhan Institute of 
Virology (WIV), in which scientists were researching coronaviruses.

But both Chinese and US researchers said there's  no evidence to support 
that theory. The high-security lab says it has no record of the novel 
coronavirus' genome, and it follows strict safety measures.

The director of the WIV, Wang Yanyi,  told China Central Television last 
weekend that the new coronavirus is genetically different from any kind 
of live virus that has been studied at the institute. Prior to that, WIV 
virologist Shi Zhengli - who collects, samples, and studies 
coronaviruses in Chinese bats - told Scientific American that she 
cross-referenced the new coronavirus' genome with the genetic 
information of other bat coronaviruses her team had collected. They 
didn't find a match.

'That really took a load off my mind,' Shi said in March, adding, 'I had 
not slept a wink for days.'

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