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  • By now, youve probably heard of the coronavirus that’s traveling the globe.

  • The disease it’s causing, known as COVID-19, and the virus itself, known as SARS-COV-2,

  • know no borders.

  • And were still trying to grasp where it will end up next.

  • So far, we know that the outbreak originated in Wuhan, Chinabut as of yet, how the outbreak

  • began hasn’t been solved.

  • Weve heard seafood, snakes, and a whole host of conspiracy theories surrounding the

  • virus's origin, but it seems that preliminary evidence may be pointing to an all-too-familiar

  • source: bats.

  • When you look at the genetic sequence of the virus, you can line it up against every other

  • known coronavirus and say, 'what are its closest relatives?'

  • It turns out that there are two viruses, one in particular that we found in China a few

  • years ago, that's extremely closely related: about 96% of the genetic sequence lines up

  • with this new virus.

  • That virus came from bats.

  • So that's really why people believe it's a bat-origin virus.

  • And this isn’t the first time bats have been identified as the potential source of

  • an outbreak.

  • In fact, studies have found that bats host a much higher proportion of zoonotic viruses

  • than any other mammal, making them disease reservoirs.

  • Viruses that cause Ebola, SARS, and MERS are all zoonotic, meaning they can cross from

  • animals to humans.

  • To better understand these zoonotic viruses, Daszak and his team have worked to sample

  • more than 10,000 bats in Southern China and most significantly, detected over 500 new

  • coronaviruses in the past ten years.

  • Now, in order to understand how SARS-COV-2 could potentially cross between species, researchers

  • are looking at it on a cellular level.

  • When we find Coronaviruses in bats in China, we analyze the proteins on the surface of

  • those viruses and say, 'are they able to bind to human cells?', and humans have cell surface

  • receptors that viruses need to be able to bind to get in.

  • And some of these bat viruses don't; some of them do.

  • So probably this novel coronavirus, already had that protein that could bind.

  • Then it needs to successfully replicate.

  • So how exactly can bats harbor all these viruses and not be affected?

  • The answer could be in how bats evolved to fly.

  • Bats are the only mammal capable of flying long distances, and use a tremendous amount

  • of energy to do so.

  • But a byproduct of these high energy demands is believed to be an increased number of free

  • radicals in cells, which in turn can damage a bat’s DNA.

  • So to overcome these harmful effects, it seems that bats have evolved genes to dampen their

  • immune response, so they don’t over-react to free radical damage caused by flight.

  • Bats have a unique adaptation of their immune system which allows them to harbor viruses

  • without these viruses causing any diseases.There's a lot of influenza viruses out there.

  • And we harbor a quite a few of them.

  • They cause us no harm.

  • And bats do exactly the same.

  • And is only after spillover to humans that some of these viruses can

  • cause illness in us.

  • So while the bats may not get sick, when viruses make the jump to species without the same

  • immune strength, like say, a human, mortality rates can be high.

  • Environmental threats like deforestation could add to the animals' stress levels, causing

  • them to shed more virus through their saliva, urine, and feces, which can later infect other

  • mammals.

  • So in these spillover events like the current coronavirus, a lot of focus often gets driven

  • towards which species is responsible.

  • But really, really important is to understand that it's about the construct that we've created

  • an environment where humans are suddenly in contact with a lot of wildlife species in

  • close quarters.

  • And so this creates an environment where viruses can spill over.

  • Bats may be the hosts to these viruses, but we can’t forget the crucial role that they

  • play in regulating insect populations and as important pollinators, with many plants

  • depending on them for their survival and propagation.

  • Some of your favorite fruits like mangos, bananas, or guava wouldn’t exist if bats

  • weren’t here.

  • I really hope people don't start getting a more negative view of bats, but just because

  • they're unlucky enough to carry some of these viruses.

  • Remember, our relationship with wildlife is what allows those viruses to get in.

  • So let's think about that and change our relationship with wildlife.

  • If you want to learn more about COVID-19, check out our video here.

  • And if there's another aspect of COVID-19 that you want to see us cover, let us know

  • in the comments below.

  • Make sure to subscribe to Seeker for all your viral news.

  • Thanks for watching, and I’ll see you next time.

By now, youve probably heard of the coronavirus that’s traveling the globe.


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B1 中級 新型コロナウイルス 新型肺炎 COVID-19

この新しいコロナウイルスはコウモリから来たのか?私たちが知っていること (Did This New Coronavirus Come From Bats? Here’s What We Know)

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    林宜悉 に公開 2021 年 01 月 14 日