Is the virus transmitted to bats, or do bats infect other wild animals? Even grasshoppers, snakes, chimpanzees and seafood can be infected with coronavirus. “Extremely complex, there are no limits to traceability. “Although it is extremely difficult to find the ultimate source of the virus, or not the so-called ultimate source, scientists from all over the world still devote a great deal of time and effort to scientific research.
In December 2019, a new type of coronavirus was spread across species, the third successful cross-species transmission virus in nearly 20 years. Compared with the previous two SARS and MERS, the new coronavirus is not weak, it is spreading faster in China.
As of 24 hours on January 26, the National Health and Reform Commission had received a cumulative total of 2,744 confirmed cases in 30 provinces (regions and municipalities), 461 cases of existing severe illness, 80 cumulative deaths and 51 cases of cured discharge. There are 5,794 suspected cases and 30,453 people are under medical observation.
Transspecies transmission has always been a desire for viruses, and they are always on the move. But who will be the natural host, who will be the intermediate host, step by step to transfer the virus to the human body?
A senior virologist stressed that the traceability of the virus is a false proposition, its source is the human current cognitive range of unabated targets, whether the virus is transmitted to bats, or bats transmitted to other wild animals? Even grasshoppers, snakes, chimpanzees and seafood can be infected with coronavirus. “Extremely complex, there are no limits to traceability. “
Although it is extremely difficult to find the ultimate source of the virus, or not the so-called ultimate source, scientists from all over the world still devote a great deal of time and effort to scientific research. Beyond the source, humans also need to find fulcrums for viruses to cross species, thereby preventing the spread of viruses to humans.
And this time, how did the new coronavirus come to Wuhan? Who did the fulcrum to cross to humans? To be clear about this, there are still many gaps in epidemiological data.
There is growing scientific evidence that the touchable source of the new coronavirus is directed at bats.
A Novel Coronavirus from Patients With Pneumonia in China, January 24, 2019, published in the New England Journal of Medicine (NEJM). The study, led by the China Center for Disease Control and Prevention, proved that the virus in Wuhan, China, is a new type of coronavirus, named 2019-nCoV, and identified 2019-nCoV, which identified its characteristics. Viral genome sequencing and other reports indicate that it is 75% to 80% homogenous to SARS-CoV and is closer to several bat coronaviruses, especially in the bat collected in southwestern China.
This conclusion, in line with the article “Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans” published on the bioRxiv pre-print platform on 23 January And its real bat origin: We found a short RdRp area in bat coronavirus BatCoV RaTG13, which was detected in the mid-chrysanthemum manta ray in Yunnan Province. This region shows high sequence homologousity for 2019-nCoV, with a genome-wide sequence of homologousness of 96.2%. The system development analysis also shows that RaTG13 is a close relative of 2019-nCoV.
This study provides more evidence of the origin of bats in 2019-nCoV. This paper is from the team of Shi Zhengli of the Wuhan Institute of Viruses of the Chinese Academy of Sciences.
The Wuhan Virus Research Institute of the Chinese Academy of Sciences has always been the backbone of Chinese scientific research, P3 Laboratory in 2005 by china’s National Accreditation Committee for Conformity Assessment (CNAS) accreditation, the new P3 laboratory in 2015 was recognized, the national high-grade biosecurity laboratory system an important component of the P4 laboratory, Recognized in 2017.
Shi Zhengli’s team previously won the second prize of the National Natural Science Award for the research results of SARS virus in the Zhongjutou manta ray in Yunnan Province.
The findings, published on November 30, 2017 in the journal PLoSS, an authoritative international journal of pathogens, entitled Discovery of a rich gene pool of bat SARS yn coronaviruses provi des new insights into the origin of SARS virus.
Shi Zhengli has previously told of her and her team’s journey to track SARS. From November 2002 to July 2003, SARS disappeared after spreading in China, and the beaver was identified for a long time as the source of the SARS virus.
But Shi Zhengli found that fruit beavers with SARS-like coronaviruses are also ill, so they may not be the source of the virus.
Since 2004, Shi Zhengli’s team has traveled throughout 28 provinces and cities in China, collecting thousands of Chinese chrysanthemum bats and analyzing the genomes of viruses in their bodies.
But the bats she found in Hubei and Guangdong carried SARS-like viruses that belonged to the coronavirus family but were not transmitted. So they continued to look.
It wasn’t until 2013, in a remote cave in Yunnan province, that they found a group of Chinese chrysanthemum bats carrying SARS-like coronaviruses, and by sequencing and sequence comparison, the team found that the SARS-like coronavirus was highly homogenous to the SARS virus that erupted in 2003.
Therefore, Shi Zhengli believes that the beaver only assumes the role of the intermediate host of SARS, that is, SARS across the species fulcrum.
On January 26, Tan Wenjie, director of the Emergency Technical Center of the CDC’s Viral Disease Institute, told the media that the new virus is 90 percent similar to the coronavirus in a bat in Zhoushan, Zhejiang Province, and that foreign studies have claimed to find another bat-carrying coronavirus with 96% of the virus.
But Even with such a high homologous nature, Tan believes that the new coronavirus cannot be identified as coming from the bat.
“Wuhan is a modern city, and it’s hard to have a bat habitat. Bats live in ancient buildings, wooden tweezers formed in the cave, in Wuhan is difficult to find bats, and Wuhan people do not eat bats habits. “A virological expert said.
If Yunnan’s chrysanthemum-headed manta rays can be considered to be the source of the new coronavirus at present, who is it to act as an intermediate host?
“Snakes also have a lot of coronaviruses, but is it a snake to a bat or a bat to a snake?” There is no evidence of this. And bats and snakes, often living in the same environment, like to live in dark caves. The virological experts said.
On January 22nd a paper published in the journal Medical Virology by a Chinese research team, including Peking University, locked the intermediate host of the new coronavirus as a snake. By studying the genetic sequence of the new coronavirus, the paper finds that a segment of the virus’s genome has been homologous, in order to find out which animal struck by this homologous recombination genome, the research team has measured the genetic code of some animals common in Wuhan seafood market, including snakes, chickens, pangolins, bats and drought-induced grasis. It was concluded that the snake was the most likely intermediate host.
“If the snake also has a new type of coronavirus, at least to show that the snake is a fulcrum for the virus to cross into humans. The above-mentioned experts said that the South China seafood market has selling snakes, through the sale, killing snakes, it is possible to infect the virus. But whether the snake is the source still needs further research to determine whether the new coronavirus in its body comes from the bat or carries itself.
It is understood that the South China seafood market has hundreds of shops selling snakes, if the snake carrying a new coronavirus is sold, human infection has become natural.
On January 26, the Cdc’s Viral Disease Institute said it had made progress in the research on the traceability of the new coronavirus, detecting for the first time 33 samples containing new coronavirus nucleic acid from 585 environmental samples at Wuhan South China Seafood Market, and successfully isolating the virus in positive environmental samples, suggesting that the virus originated from wild animals sold in the South China Seafood Market. Of these, 93.9% (31/33) of the positive specimens were distributed in the western part of the South China seafood market.
There are wildlife trades in the western part of the South China Seafood Market, especially in the area of 7th and 8th Streets in the West End, close to the inside of the market, where positive specimens are concentrated, accounting for 42.4% (14/33) of all positive samples.
As a result, there is high suspicion that the outbreak is linked to wildlife trade.
In addition to wild animals, what other animals can carry the virus to Wuhan?
“China DISEASE Control confirmed that there is a large number of new coronavirus 2019-nCoV in the south China seafood market environment, which proves that it is possible that the virus is also on seafood, and that when merchants rinse seafood with water, the virus will enter the environment. The virus could survive in seawater for up to three months. The experts said.
Seafood carries viruses on land and in the air without precedent. The 1988 hepatitis A pandemic in Shanghai was caused by the contamination of the East China Sea seafood wool by the hepatitis A virus, which sickened nearly 300,000 people.
The possibility of virus contamination of seafood was also confirmed in a paper published by the Ningbo CDC in cooperation with the China Center for Disease Control and Prevention.
What is the fulcrum of the new coronavirus and how many is there still requires further scientific evidence.