The outbreak of novel coronavirus pneumonia is fantastic for ordinary people, but for some scientists studying bats, it is already doomed. Bat virus has been infecting people for many years in China.
The outbreak of novel coronavirus pneumonia is fantastic for ordinary people, but for some scientists studying bats, it is already doomed.
Kevin olival, an American disease ecologist, has long studied bats, capturing them in China and other parts of Asia and collecting their body fluids. Olivars organization, the eco Health Alliance, a non-profit research organization, also has long-term cooperation with Chinese researchers.
Olivar recently revealed his amazing findings in thousands of bat samples collected in China: we have found about 400 new coronaviruses in total. This means that there are 400 candidate viruses that could lead to an outbreak.
For more than a decade after the outbreak of SARS, researchers have been searching for the next source of virus that will pose a major threat to human beings. Olivars study also found that bat virus infection has occurred in China for many years, which scientists call spillovers.
NPR accompanied Olivar to Borneo, Borneo, Malaysia to collect bat samples. On the edge of a tropical rainforest, Olivar sits in a makeshift outdoor laboratory. On a folding table, he put a female bat.
During hours of painstaking sample collection, Olivar would occasionally comfort bats that writhed in pain from oral swabs. After sampling, as a reward, he gave the bat some mango juice.
In Chinas Hubei Province, Tian Junhua, a young scientist at the Wuhan CDC, is doing the same. In a documentary released in December last year, Tian Junhua has been out in the daytime and at night in the past decade. He has visited dozens of bat caves in Hubei Province and collected precious bat virus samples.
In the past ten years, we have visited every corner of Hubei Province, explored dozens of undeveloped caves and studied more than 300 kinds of virus vectors, Tian said
If our skin is bare, its easy to get in touch with bat feces, pollutants, he said. The researchers wore protective clothing, goggles, masks, headlights, flashlights We are well prepared for this unknown adventure.
This is a war without gunpowder. In the film, two researchers armed, climbed the rugged cave wall to remove the captured bats. A staff member wearing gloves grabbed the bat. Tian Junhua put the collected samples of the bat into the specimen box, and then put the bat back into the cave.
In May 2017, a report by Xinhua News Agency described Tians work: the environment for collecting bat samples is extremely bad. There is a stench in the bat cave. Bats carry a large number of viruses in their bodies. If they are not careful, they are at risk of infection. But Tian Junhua is not afraid to go to the mountain with his wife to catch Batman.
Tian Junhua summed up the experience that the most bats can be caught by using the sky cannon and pulling the net. But in the process of operation, Tian Junhua forgot to take protective measures. Bat urine dripped on him like raindrops from the top. If he was infected, he could not find any medicine. It was written in the report.
The wings of bats carry sharp claws. When the big bats are caught by battools, they can easily spray blood. Several times bat blood was sprayed directly on Tians skin, but he didnt flinch at all. After returning home, Tian Junhua took the initiative to isolate for half a month. As long as the incubation period of 14 days does not occur, he will be lucky to escape, the report said
We dont know if Tian Junhua has been so lucky on batcatching. But scientists have shown that bat viruses can infect people directly, without the need for so-called intermediate hosts..
Infected villagers unconsciousness
Olivar said his research project, which collected bats with his colleagues, found that bat viruses do not need to mutate in another animal to infect humans. These steps are unnecessary. What we have shown is that the SARS related viruses in these bat populations have the potential to enter human cells directly without infecting another host to cause additional mutations.
This means that the path to new outbreaks may be much more direct. And this direct route of infection has been achieved in the laboratory: researchers put a coronavirus with a very similar gene to SARS virus in a culture dish with human cells, and the virus successfully infected human cells.
This principle was suggested in an article published in nature in 2013. At that time, US scientists pointed out that bats may carry the next SARS like epidemic virus and can directly infect human cells. In this scientific paper, for the first time, scientists have revealed that it is possible to transmit SARS like virus directly from natural host to human without intermediate host media.
This conclusion was further confirmed in another paper published in the journal Nature Medicine in 2015. The experimental data in this paper confirm that a bat coronavirus with shc014 spike has the ability to directly infect human respiratory tract cells, but reduces the risk of potential cross species transmission. Shi Zhengli, a researcher at the Wuhan Institute of Virology, participated in the study.
Olivar said the fact that bat coronavirus has the ability to infect people at least in the laboratory environment raises the obvious question: is there evidence that these viruses are infecting people in the real world?
For this reason, researchers began to take blood samples from Chinese villagers living near bat cave in Jinning, Yunnan Province, a few years ago. In the study, 218 local villagers serum samples were tested to confirm that 3% of the villagers serum antibody tests were positive, but they did not realize that they had obvious discomfort symptoms in the past year.
This study strongly suggests that SARS coronavirus has a high potential to infect people directly without intermediate host. The results were published in the English journal virogica Sinica of Wuhan Institute of Virology in February 2018. Shi Zhengli and Peter daszak, chairman of the ecological health alliance, are both authors of the article. But up to the time of publication, there is no obvious evidence that SARS coronavirus has directly infected human beings.
Li Hongying, an ecologist at the ecological health alliance, said: many of these people may have inadvertently come into contact with bats saliva, urine or feces. In some places, bats live in peoples homes, and some people have the experience of killing bats directly.
Local people are also willing to go to bat cave for summer. When Li Hongying and others went to bat cave for sampling, they often saw some beer bottles or water bottles, suggesting the frequent contact between bats and people.
Li Hongying said that she and her colleagues have checked the blood of villagers for many times to find signs of bat coronavirus infection recently. Every time, they will find that bat coronavirus has invaded human beings, but small outbreaks in these local areas have not been found or reported.
This discovery is a huge signal of danger. There are already signs that these SARS related viruses are invading the human body, even if they do not cause any obvious symptoms and diseases. In fact, people may even have symptoms, but health authorities have never noticed it, Olivar said
Ratg13 bat coronavirus appears for the first time
This phenomenon implies novel coronavirus outbreak may foreshadowing factors. Researchers from the Wuhan Institute of Virology and Wuhan Jinyintan hospital compared the new virus with bat samples they collected from the beginning of the outbreak. They found a very close pairing - a coronavirus (ratg13) from a Chinese species of Rhinolophus, which Shi Zhengli found in Yunnan Province.
This article, with Shi Zhengli as the corresponding author, was published in the journal Nature on February 3 and caused a stir in the whole scientific research field. The novel coronavirus genome novel coronavirus genome was compared with the early detection of the coronavirus genome. The results showed that the whole genome sequence of the RaTG13 coronavirus in this bat was 96.2% consistent with the human coronavirus infection.
Scientists use very shocked to describe the mood after seeing the report. Novel coronavirus RaTG13 is the first reported virus in the world, and RichardEbright can be regarded as a coronavirus with the new coronavirus, Professor Waxman told the first financial reporter. RaTG13, or a novel coronavirus, is closely related to bats.
In the view of virus taxonomists, they may call them the same kind of virus, Olivar said
Professor ebright also pointed out the key core: the degree of similarity between ACE2 receptor of Chinese Rhinolophus and that of human body is the same as that of other potential intermediate hosts other than non-human primates. This suggests that the epidemic, which has infected tens of thousands of people, may have originated directly from bats.
Although novel coronavirus can not directly infect humans without intermediate host, there is no direct evidence that new coronavirus can also infect humans like other SARS coronaviruses. However, scientists who have studied the evolution of virus have told the first financial reporter: bat is the natural host of coronavirus, carrying many coronaviruses, which can directly cross the barriers between species and directly infect. People.
What changes has the mysterious bat coronavirus experienced and how has it been brought into the population of Wuhan? Scientists all over the world are looking for answers. The more important conclusion is clear that these SARS related coronaviruses in bats are actively invading humans, Olivar said He added that not all viruses can cause deadly epidemics. But the more frequent this spillover occurs, the greater the chance of an outbreak.