The genetic sequence information of 15 bats with SARS-like coronaviruses confirms that bats are the natural hosts of SARS viruses.

The genetic sequence information of 15 strains of bat SARS-like coronaviruses is entered into bioinformatics derivation software, which is similar in some regions and varies in some regions.
software began to run, Hu , an assistant researcher at the Wuhan Institute of Viruses of the Chinese Academy of Sciences, sat alone in front of a computer in the lab waiting.
a few minutes later, a series of high and low lines appeared on a computer screen.
these lines mean that the genome sequences of several of the 15 viruses, after a series of recombinations, are highly consistent with the genetic sequences of SARS viruses that have caused the outbreak of "atypical pneumonia."
15 strains of the virus, all from a bat cave in Yunnan, China.
the moment he saw the result, Huwas calm.
he and his team, after genome-expanding the viruses to sequence results, have long speculated on the current derivation results.
at a later group meeting, Hureported the results of software derivation to Shi Zhengli, the head of the research group.
November 30, 2017, the team's paper on the origin of SARS coronavirus estocory was published online in the Public Library of Science - Pathogens . On December 1st,
, the paper was covered in a news column in the journal Nature.
", "We have revealed the possible recombination origin of the SARS coronavirus.
", Hutold China Youth Daily Zhongqing Online.
bats are the natural host of the coronavirus, the fruit beaver has not been wronged 15 years have passed, Hustill remember in 2003, he is reading high school, Wuhan summer extremeheat, but people go out wearing a thick mask.
" ordinary mask is not very useful, figure a psychological comfort.
" Huwhile recalling, while laughing helplessly.
to this day, the word "SARS" still surprises people who have experienced it.
in yao Tienan, director of the public service department of the Beijing Municipal Health and Family Planning Commission, said the SARS virus was simply "coming and going without a trace".
it emerged quietly in the winter of 2002 and broke out in the spring of 2003, "highly contagious, spread fast and high mortality".
as the flow of infected people spreads throughout the country and around the world, with CASES of SARS reported in 24 provinces (regions and municipalities) Chinese mainland.
for the first time in its history, the World Health Organization has issued global travel advice to get people to travel with caution.
the disease is known as Severe Acute Respiratory Syndrome, or SARS. The
outbreak lasted eight months, swept 26 countries, infected 8,096 people and killed 774.
, China reported 7429 cases and 685 deaths.
since then, SARS has all but disappeared and there has been no major outbreak.
" We didn't know what the pathogen was at first.
," Hu said .
in the lab, the scientists were busy.
soon, a virus was isolated from the patient.
it looks like a crown, with many protrusions of arrangement rules on the surface.
After genetic sequencing, the researchers found that it was a "new coronavirus that we never knew."
where did it come from? The beaver became the primary "suspect".
in Guangdong, a province where game consuming is consumed, initial cases include cooks who have dealt with game, wildlife market vendors, and so on.
the SARS outbreak, they were exposed to beavers.
soon, researchers detected SARS coronavirus from beavers in the wildlife market, "with a high correlation with the whole genome sequence of the SARS virus that is prevalent in the population."
researchers confirm that beavers are indeed the direct source of SARS virus transmission to humans.
" however, the direct source does not equal the underlying source.
"huexplained to China Youth Daily Zhongqing Online that the most important thing to find the root cause of a virus is to find its natural host.
Viruses are also creatures, and they are not intended to kill all hosts, but to "survive," according to Hu .
have some hosts, can carry a certain type of virus in the body for a long time, but will not be sick or even die, but with the virus coexisting harmoniously, in the entire population, the same virus has a certain natural infection rate.
such hosts, biologically known as natural hosts, are like "water reservoirs" of viruses.
a series of animal experiments have shown that the sars coronavirus, which is fatal to humans, can also make beavers sick.
on the other hand, extensive epidemiological findings on wild and farmed beavers also show that none of them are infected with SARS virus.
fruit beavers are just intermediate hosts.
2004, Shi Zhengli, a researcher at the Wuhan Institute of Virus Studies of the Chinese Academy of Sciences, and Zhang Shuyi, a researcher who was still working at the Institute of Animals of the Chinese Academy of Sciences, embarked on a journey to track the source of the SARS coronavirus.
1990s, there were two human-animal viral infections, which broke out in Australia and Southeast Asia, all from the same animal, the bat.
" one is transmitted from bats to pigs and then to humans.
another intermediate host is a horse.
this raises the possibility for the team that tracks the origin of the SARS virus, whether the source of SARS is also a bat.
," Hu said .
is a special place for researchers who study viruses.
their scientific name is winged, in mammals, is the second largest group after rodents, the species of mammals accounted for 20% of the number of species, widely distributed throughout the world.
chrysanthemum bats are one of the common bat species in China, with an average life span of 25 years.
bats are also natural hosts of many viruses, including Ebola virus, Marburg virus, rabies virus, Hendra virus, Nipa virus, etc.
because bats have a special immune system, they carry the virus but rarely develop the disease.
over the course of evolution, bats have become the natural hosts of hundreds of viruses.
researchers began tracing the SARS coronavirus in the bat population.
Shi Zhengli and Zhang Shuyi led a joint research team to collect swabs, pharynx and blood samples from 408 bats in Guangdong, Guangxi, Hubei and Tianjin.
in the lab, the researchers tested the samples for antibodies and nucleic acids.
they detected SARS coronavirus antibodies in the daisy-haired population.
in different regions of the chrysanthemum, "a variety of genetically diverse coronavirus nucleic acids similar to the SARS virus" were detected.
sample also contained a bat coronavirus, and full-length genome sequencing showed that it was 92% similar to the SARS coronavirus that can infect humans and fruit beavers.
2005, the findings were published in the journal Science.
" bats are the natural hosts of a class of coronaviruses associated with SARS coronaviruses, known as SARS-like coronaviruses, which cause SARS outbreaks and are part of the family of coronaviruses.
," the paper reads.
"The beaver is a direct source of human infection with SARS virus, as an intermediate host, is not wronged."
it has also proved that the removal of beavers from the wildlife market has indeed helped to contain the outbreak.
but when it comes to the underlying source, bats that are natural hosts are more likely.
Shi's paper is our first milestone in our study of SARS coronavirus tracing.
," Hu said .
isolated from the live virus of the first bat SARS-like coronavirus to confirm that bats are the natural hosts of SARS-like coronavirus, the journey of tracing is only just beginning.
Despite the similar structure of the genome, the bat SARS-like coronavirus found by the team at the time was very different from that of the SARS virus infected with humans and beavers.
this key gene is called the hedgehog protein gene, also known as the "S gene".
"the s protein of the coronavirus is responsible for the binding of the virus to the receptor son of the cell surface, the receptor binding, the virus can invade the cell, establish infection.
the binding of the virus to the receptor is specific, the S gene is different, the virus receptor may be different.
it's like what key with what lock, and if you can't find a receptor that can be used, the virus can't infect cells.
so, the S gene has an important role to play in determining which cells can be infected by coronaviruses, which hosts they infect, and how pathogenic they are.
" Husaid, "The S gene is so different that these SARS-like coronaviruses are likely not to infect people or beavers like the SARS virus."
", in addition to the S gene, there are several secondary genes, and it is not entirely consistent.
this shows that the previously discovered virus, and the direct ancestor of SARS virus there is not a small gap, can not confirm the cause of SARS outbreak of the virus must be the source of the bat.
in order to find more evidence, the research team in southwest China, south China, north China, China's wilderness ridges continue the research journey, as far as Tibet Mote, Yunnan Xishuangbanna.
team member Luo Dongsheng, who had just joined the sampling team for nearly two years, recalled that he once climbed several hills and drilled seven bat holes in one afternoon.
encountered a low hole, had to go forward.
sometimes, the bat cave is not far from the mountain, a straight line distance of only a few dozen meters, walking past but it takes a few hours.
the road is full of thorns and needs to be cut out of a road with a knife or a hoe.
more often, Luo Dongsheng would lie down by the car's co-driver window, holding up his telescope and looking out of the window.
the car was driving on the mountain road, he needed to determine where there might be a bat hole.
as the team leader, Shi Zhengli often led the team to climb the mountain drill hole.
sampling is usually a group of four people.
wearing N95 masks, gloves and headlights, coats, and netting birds at the mouth of the bat in the evening.
night, they took off the fallen bats from the bird catcher's net, made up workbenches in the wild, and took swabs overnight.
they catch bats, use swab swabs soaked in physiological saline, and insert them into the bat's anus to swaths to swaths.
the swab is extracted, the bat is released.
", Mr. Shi has always insisted on no-infringement sampling, try not to cut bats, sampling also to minimize physical harm to bats.
," Luo Dongsheng said.
some bat populations are small, and destructive sampling is likely to be devastating for the entire population.
bats play an important role in maintaining the ecological balance, killing a large number of bats will cause significant damage to the ecosystem.
the risk of being bitten by a bat remains despite wearing gloves. Fan Yibi, a member of the
study team, drew a picture of the length of a bat's teeth, and not long ago his index finger was bitten by a bat.
", we get the rabies vaccine in advance before sampling in the wild.
is the most dangerous of the viruses carried by bats.
," Fan Yi said.
Until 2011, in a bat cave in Yunnan, the team finally found the clues they had been looking for. "For the first time in a sample from this hole, we have detected a SARS-like coronavirus S gene that is more similar to the SARS virus,"
.
although other gene fragments are not exactly the same, but compared to other sampling sites, Yunnan this hole, more worthy of our attention.
" From this year on, this bat cave in Yunnan was designated as a long-term sampling site.
until October 2015, every year in the spring and autumn, Shi Zhengli's research team will be there.
" spring is the breeding season for bats, and autumn is the season with the highest rate of positive coronavirus.
," Huexplained.
the temperature of the cave is between 22 and 25 degrees Celsius, with humidity of about 85% to 90%.
is home to a large population of chrysanthemum bats.
, similar bat caves are not uncommon throughout Yunnan.
at dusk, the team laid a cloth on the floor of the cave and collected fresh bat droppings the next morning.
about 1 gram of each stool sample, placed in a 1 ml of collecting solution, brought back to the lab and stored in a freezer at minus 80 degrees C.
in the lab, the virus RNA in the sample was extracted.
2013, the laboratory of wuhan virus research institute of the Chinese Academy of Sciences isolated the first live virus of bat SARS-like coronavirus from fecal samples, which was named WIV1 (WIV is the English acronym for Wuhan Virus Research Institute).
it is closer to the SARS coronavirus than any previously discovered bat SARS-like coronavirus, which is the similar S gene that allows the bat SARS-like coronavirus to use the same receptors as the SARS virus and to infect human cells.
published in the November 2013 issue of the journal Nature.
second milestone.
the origin of SARS virus, it can finally be answered by the successful separation of WIV1, so that scientists around the world on the origin of SARS virus differences, debate, become "consistent."
the hunt, which has been going on for years, is becoming clear - the SARS coronavirus originated in chrysanthemum bats. "But we haven't found the most direct ancestral strain of the SARS virus in the bats at this sampling point in Yunnan, "
.
that is, we haven't found a bat virus that is highly similar to the SARS virus on all the genes.
"," according to Hu , there was an information gap in the entire chain of evidence at the time. Br.