Virological studies have found that these three coronaviruses are new in this century, and they are all considered to come from wild animals. Almost all viruses can be traced back to bats. However, although bats are the natural reservoir of these three viruses, it has been found that the formation of these three viruses has also experienced the relay of many wild animals. They evolved and spread among many wild animals and finally spread to humans.
For example, the COVID-19 virus that caused the COVID-19 outbreak is thought to originate from bats, but it is likely to spread among snakes, minks, pangolins and other animals. The newspaper reported on February 28th that Liu Long from the People's Hospital affiliated to Hubei Medical College and Wu Jianguo from Jinan University published a paper in the Journal of Medical Virology on February 26th, saying that turtles (western scarabs, green turtles and Chinese soft-shelled turtles) may also be potential intermediate hosts transmitted to humans by novel coronavirus.
Is it that wild animals want to fight back against humans? Besides bats, at least four kinds of animals are known to have participated in the manufacture of COVID-19. How are they made? Based on the composition and differences between the spike protein of coronavirus and the host ACE2 receptor, the research team predicted the potential intermediate host in novel coronavirus, focusing on comparing the spike sequences of novel coronavirus with SARS-CoV, bat SARS-like CoV and other coronaviruses. This is helpful for evolutionary analysis and finding possible virus sources. In addition, the analysis of the structure of ACE2 and the comparison of binding motifs are also helpful to distinguish potential hosts, and studying the evolutionary relationship of receptor binding region (RBD) sequence in spike protein is helpful to understand the origin trend of the virus.
The results showed that the whole genome of bat SARS-like CoV rat 13 had 96.2% sequence identity with that of novel coronavirus, and SARS-CoV was the most widely distributed coronavirus in pangolin specimens. At present, there is no direct evidence that bat SARS-like CoV has ever infected humans.
Pangolin SARS-like CoV SRR 10 168377 and bat SARS-like CoV rat 13 are only 85% identical. Comparatively speaking, the coronavirus proposed by turtles and pangolins is closer to humans than bats. This indicates that turtles and pangolins may be the intermediate hosts of novel coronavirus, but they are not exactly the same as COVID-19 infected by humans.
Many people like to eat soft-shelled turtles and soft-shelled turtles, thinking that they have nourishing effects, but they don't know that soft-shelled turtles are also soft-shelled turtles? Virus warehouse? , carrying at least dozens of viruses, such as Rainbow Frog Virus (RV), Nino Virus (NV), Papillomavirus (PV), Turtle Rainbow Virus (STIV), Turtle Systemic Septicemia Globovirus (STSSSV), Turtle Parvoribonucleic Acid Virus (ToPV) and Turtle Hemorrhagic Syndrome Virus (TSHSV).
Therefore, whether you are preying on wild animals or getting along with wild animals, you need to be careful about the contact and infection of viruses. However, some friends may say that human beings have been catching and using wild animals since ancient times. It can be said that they have been dealing with wild animals for millions of years. Why can't people touch wild animals now?
There are two main points that many friends may not realize. First, it was not without problems for humans to catch wild animals before, but the medical conditions were backward at that time and most people didn't know it. In fact, in the history of human development and evolution, there have probably been many incidents similar to the current epidemic in COVID-19. Of course, many people have lost their lives due to infectious diseases of wild animals. There have also been many plague incidents in history, including hundreds in China. These events are likely to be related to wildlife. People often say that after a catastrophe, there will be a catastrophe. It is precisely because many wild animals will also encounter disasters after the disaster, and some viruses may be released, and people's living and sanitation conditions will also decline. It is difficult to prevent and control the invasion of virus, and a plague may occur.
The second aspect is that with the improvement of human living standards and medical and health conditions, the human body has been well protected, and the immune system no longer needs to stop the invasion of viruses, resulting in the deterioration of human immune function and even no response to some viruses. In this way, some wild animals can be immune to viruses, but humans can't, so humans will have symptoms. COVID-19, which caused the COVID-19 epidemic at present, belongs to this virus, because we haven't found any wild animals with symptoms of COVID-19.
At present, there is no conclusion about the true origin of COVID-19 and when interpersonal communication occurred. As Academician Zhong Nanshan said: Although the COVID-19 epidemic mainly broke out in China, the virus may not have originated in China, and there have been many cases of COVID-19 patients unrelated to China in Japan, South Korea, the United States and Iraq, so the source of COVID-19 and the first case of interpersonal transmission remain a mystery. Whether there is deep water in it needs further study!