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Nature’s concern:novel coronavirus is spreading among wild animals

With the pandemic of novel coronavirus, a considerable number of humans in the United States and Canada have been infected with novel coronavirus. At the end of 2021, an article was published in Nature Many wild white tailed deer in North America have been infected with new crown disease and even a variety of new crown variants. This indicates that novel coronavirus may survive in wild white tailed deer for a long time, which brings a new way for the further evolution of novel coronavirus and its re transmission to humans.

At present, there is no evidence that novel coronavirus in wild animals will spread to humans, but scientists are increasingly worried about these whiteTailed deer ClubBecome a novel coronavirus library, thus generating newMutant and bringNew outbreaks.Other studies suggest that Omicron lurked in animal hosts for a period of time before a large-scale human outbreak.

So far, these white tailed deer infected with novel coronavirus have not shown any symptoms, but they may spread novel coronavirus to other livestock or wild animals. Once novel coronavirus is widely spread in wild animals, the epidemic will become difficult to control.

Since the beginning of the covid-19 pandemic, researchers have been concerned about the infection of wild animals. In order to monitor specifically, the researchers first studied ACE2, which is the receptor protein of novel coronavirus invading human cells. Animals with ACE2 protein similar to human are at risk of infection with novel coronavirus. Scientific research teams around the world have begun to test these animals for experimental infection, and have determined whether they can infect and spread novel coronavirus.

Research shows that primates, cats, deer mice, raccoon dogs, minksWhite tailed deer, etcAnimals have the potential to infect and transmit novel coronavirus.

In January 2021, USDA researchers found that,Captive whiteTailed deer canInfected with novel coronavirus and passednoseMucus and feces spread to other white tailed deer in adjacent fences.These deer will produce antibodies against novel coronavirus within one week after infection with novel coronavirus without obvious symptoms. These findings are surprising because cattle, sheep and other ungulates are not infected with novel coronavirus.

In July 2021, researchers at the National Wildlife Research Center were in the preprint bioRxiv Publish papers. They tested 385 blood samples collected from white tailed deer from January 2021 to March 2021, and found that nearly 40%of the blood samples could detect antibodies against novel coronavirus, indicating that a considerable proportion of white tailed deer have been infected with novel coronavirus, which is alsoIt is the first time that wild animals are widely exposed to novel coronavirus

In fact, in 2020, the beginning of the new crown pandemic, scientists have started to detect white tailed deer, but the detection in 2020 did not find that they were infected with novel coronavirus.

However, in 2021, the situation was completely changed. A large number of wild white tailed deer were found to be infected with novel coronavirus in various test samples from January 2021. This is just after the peak of human infection, especially in the United States.The mutant strains of novel coronavirus detected in white tailed deer flocks also proved that human beings have changed the latest neocoronavirus for many timesPlant propagationTo the wild white tailed deer.

Since January 2021, researchers have detected wild white tailed deer infected with novel coronavirus in 24 states of the United States, as well as in various regions of Canada. At the end of December 2021, the wild white tailed deer on Staten Island in New York City also detected the Omicron variant. In March, 2022, novel coronavirus was detected in wild mule deer in Utah.

However, the transmission of novel coronavirus in wild deer seems to be limited to North America. So far, no novel coronavirus infection has been detected in wild deer in Europe. Biological differences cannot explain this phenomenon. From the perspective of ACE2 receptor, the susceptibility to new crowns of European deer and North American white tailed deer is similar. This indicates that the transmission of novel coronavirus in white tailed deer in North America is probably due to the high population density of white tailed deer and frequent contact with humans. In North America, wild deer often walk around in the wild and even into people’s backyard, but this is rare in other places. Wild animals usually live in protected areas.

So far, it is still unclear about these wild animalsWhite tailed deer areHow to infect novel coronavirus.It may be due to direct contact, such as when humans touch white tailed deer directly or feed them. In some states of the United States, some people specially raise white tailed deer, and some treat injured white tailed deer, which may lead to their close contact with humans. When they return to the wild after being infected with novel coronavirus, they may spread novel coronavirus to other white tailed deer. But these contacts are difficult to explain such a large proportion of transmission in such wild deer herds. Therefore, there is also a view that these wild white tailed deer may be infected with novel coronavirus through environmental contact, but this has not been strictly confirmed.

Another view is that the waste water polluted by novel coronavirus may infect the white tailed deer by flowing into the wild water source. Many studies have found novel coronavirus RNA in sewage, but no infectious novel coronavirus strain has been isolated from sewage.

In addition, it is also reported that wild cats or minks can be used as vectors to infect white tailed deer with novel coronavirus.

The above views seem to have some truth, but they can not fully explain the large-scale transmission of wild white tailed deer. It is likely that they are not infected and transmitted by a single cause, but caused by a variety of reasons.

White tailed deer are一种群居动物,它们通常在几平方公里的范围内活动,然而,在每年十月到第二年二月的繁殖季,这种情况就会发生变化。在此期间,鹿群会相互接触并大大扩大行动范围。它们之间在接触时会有很多nose子碰nose子的接触,这就导致一旦一只鹿感染了新冠病毒,它们的行为方式很容易造成新冠病毒在种群内的广泛传播。

The Middle East respiratory syndrome (mers COV), which broke out in the Middle East before, is also a fatal infectious disease caused by coronavirus. The virus was transmitted from camels to humans. Therefore, scientists are worried that white tailed deer will become the host of novel coronavirus, which will spread to humans.

Once novel coronavirus has established long-term infection in white tailed deer, it may mutate, evolve, and recombine with other coronaviruses, which may infect other deer or grazing animals such as sheep, goats, cows, etc.

More and more studies have proved this. Novel coronavirus shows signs of long-term evolution in white tailed deer. In February this year, a study published by researchers from the Canadian food inspection agency in the preprint biorxiv showed that the novel coronavirus infected by white tailed deer sampled in Ontario had 76 mutation sites compared with the original newcrown virus. These mutations led to changes in the S protein of the new crown invading the host cells, which was the key to the success of the highly transmissible variant. The analysis of the genomes of these viruses showed that the closest relative was the novel coronavirus that infected humans a year ago, which indicated that the virus had spread among white tailed deer for a long time.

In February, a paper published in the preprint medrxiv by the University of Pennsylvania showed that a new crown alpha variant different from the human genome was found in the local white tailed deer, indicating that the alpha variant has evolved independently in the white tailed deer since it was infected with the white tailed deer.

More importantly, studies have found that the genome of novel coronavirus in a person in Ontario is highly similar to that of novel coronavirus found in white tailed deer. Despite the lack of key evidence, scientists suspect that this person may have been infected with novel coronavirus from white tailed deer. If this is confirmed, the spread of white tailed deer to humans will be worrying.

In addition, white tailed deer, like humans, can be infected with novel coronavirus for many times. For example, studies have found that white tailed deer infected with Omicron also have antibodies against Delta, which shows that white tailed deer can be infected with novel coronavirus for many times, which also means that novel coronavirus will be difficult to disappear from white tailed deer, thus continuing to spread.

Original link:

https://www.nature.com/articles/d41586-022-01112-4