Since the beginning of the year, the whole world has been following the development of the situation in China in connection with the outbreak of the new coronavirus 2019-nCov. Every day, new data on the number of infected, which is constantly growing, comes from the Middle Kingdom. Scientists have found that coronavirus is able to be transmitted from person to person at the stage of the incubation period - that is, until the first symptoms appear, which greatly complicates an already difficult situation. Meanwhile, researchers are trying to understand the origin of 2019-nCov. At the moment, there are two hypotheses: the gradual mutation of the virus among wild animals on the market in Wuhan and the leak from the laboratory for the study of deadly viruses, which is located near the epicenter of the outbreak.
Where do new viruses come from in the 21st century?
The emergence of new viruses today should not surprise anyone - because viruses, like all organisms on our planet, are developing and adapting to new conditions. Due to the growing population of the Earth and the amount of meat consumed, a variety of viruses got carte blanche in their hands: a large accumulation of mammals and poultry on farms, where sanitary standards are not always observed, is becoming an ideal environment for the multiplication of viruses. At least that was the case with bird and swine flu. Avian influenza is an extremely common bird disease in the wild, but when this strain gets into domestic hens, they die quite quickly due to lack of immunity. A frequent contact of sick birds with humans gradually allows the virus to mutate, which was the reason for the appearance of a strain of bird flu that is fatal for humans.
A similar situation was observed during the outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003: the bats that live in a cave in Yunnan province in China turned out to be carriers of the virus. In general, bats do not get sick. So, recently we told you about the threat of the Nipah virus pandemic, the carrier of which are the fruit bats of the genus Pteropodidae. Rising temperatures due to climate change is also a threat to the spread of other equally dangerous diseases.
Under such conditions, animals were kept at the seafood market in Wuhan
The 2019-nCov genome, as scientists have found, is almost 80% identical to the SARS genome. However, mortality from SARS was significantly higher than from the new coronavirus. But if bats turned out to be the cause of SARS, then where did 2019-nCov come from in the Wuhan seafood market? According to CNN, scientists narrowed down the causes of the spread of coronavirus to interspecific transmission of the pathogen from bats or snakes and a potential laboratory leak in Wuhan.
Reason # 1: passing 2019-NCoV to bat snakes
Given the reasons for the occurrence of SARS and MERS, it is not surprising that the first suspicion of scientists fell on bats. Subsequently, it became known that in the seafood market in Wuhan, live wildlife was traded, which citizens of the Celestial Empire often use for culinary purposes. So, the researchers suggested that from bats, the coronavirus was transmitted to snakes and, ultimately, to humans. Recently, social networks of Chinese gastronomic hobbies, including bat soup, have been harshly criticized. In 2017, Wang Mengyun, a Chinese celebrity, apologized after the video in which she ate a fried bat became viral. The question of whether coronavirus or other forms of the virus can be transmitted to humans after heat treatment remains open.
On the left in the photo is a bat soup. Right, Chinese actress Wang Mengyun is eating a fried bat.
As researchers write in a paper published in the Journal of Medical Virology, snakes are the most likely reservoir for 2019-nCoV. Despite criticism of this work in the scientific community, experts believe that the presence of a large number of wild animals in cages on the market in Wuhan represents ideal conditions for the propagation and interspecific mutation of viruses. Previous studies have shown that the virus can spread from live bats to poorly regulated markets where live animals are traded.
Reason # 2: Potential Leak from Deadly Virus Lab
In 2017, the National Biosafety Laboratory was opened in Wuhan to study the world's most powerful viruses and pathogens. However, even then, researchers expressed concern about a possible leak from the laboratory. Due to the fact that in Chinese laboratories, scientists are testing pathogens on animals, including monkeys, it is possible that pathogens can break out in various ways. According to some experts, due to pathogens, monkeys may exhibit volatile behavior.
Pictured is Hubei Province. Red indicates the distance from the seafood market to the virus research lab
They can run away, scratch, bite. Nevertheless, based on the development of the virus and research that has emerged in recent weeks, interspecific transmission from bats or snakes to humans is a more likely cause of coronavirus than a possible leak from the object. However, it is impossible to completely exclude the version of a leak from the laboratory. So, in 2004, a SARS leak occurred in one of the laboratories in China.
