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The Weird Reason Rabies Is So Deadly - Video học tiếng Anh
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The Weird Reason Rabies Is So Deadly
The Weird Reason Rabies Is So Deadly
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0:00
Rabies is one of the deadliest [music]
0:02
diseases we know of. If you don't get
0:04
treatment soon after getting exposed,
0:06
you are almost [music] certain to die.
0:08
But rabies intent isn't actually to
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kill,
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>> [music]
0:11
>> it's to control. Hi, I'm Kate and this
0:14
is MinuteEarth. Pathogens have one goal,
0:17
to replicate and spread to new hosts.
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And they use all kinds of creative
0:21
strategies [music]
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to accomplish that goal, like inducing a
0:24
poop-tacular amount of diarrhea, or
0:26
making their hosts sneeze or cough all
0:29
over the place, or causing [music]
0:31
oozing germ-filled sores. We made a
0:33
video all about this. But most of these
0:35
strategies [music] share the same
0:37
general approach, cause physical changes
0:40
in the host that make transmission more
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likely. [music] Rabies takes a different
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approach. It causes behavioral changes
0:46
in the host to make transmission more
0:48
likely. Rabies is transmitted through
0:50
[music] saliva. In order to infect a new
0:52
host, that virus-laden saliva needs to
0:54
make its way into a different critter's
0:56
body.
0:56
>> [music]
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>> Once it's in there, unlike most
0:58
pathogens which move through the
1:00
bloodstream, rabies viruses travel
1:02
through [music] their host's nerves.
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It's not a fast way to travel. The
1:05
viruses only advance a few inches
1:07
[music] a day, but it helps hide them
1:09
from the host's immune system, and it's
1:11
a direct route to [music] rabies desired
1:13
destination, the brain. There, the
1:15
viruses start to build up. Scientists
1:17
[music] don't totally understand the
1:19
details, but the viruses seem to bind to
1:21
receptors that allow brain cells [music]
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to communicate with each other,
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basically seizing control of the brain.
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The host becomes less fearful and more
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aggressive, which means it's more likely
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to come into contact with and bite
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another potential host, passing along
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the virus. Well, at least that's the
1:38
case in animals like dogs and bats.
1:41
Humans infected with rabies sometimes do
1:43
act differently. [music]
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They may get agitated and anxious, but
1:47
they don't go around biting people.
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Probably because, unlike rabies normal
1:52
hosts, [music] humans instincts to bite
1:54
aren't that strong in the first place.
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As a result, humans are almost always a
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dead end host for rabies. [music]
2:01
And uh speaking of dead, the clever way
2:04
that rabies tries to ensure its
2:06
transmission by interrupting the brain's
2:08
normal operation causes serious
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collateral damage for its hosts, [music]
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no matter what species they are. Because
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the brain is the control center, not
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just for a creature's behavior, but also
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for its entire body. If brain cells
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can't communicate with each other
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properly, they can't coordinate the
2:24
signals needed to keep the host
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breathing, [music] its blood pumping,
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its muscles moving. These systems spiral
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into more and more disorder. Eventually,
2:33
[music]
2:33
they fail completely and the host dies.
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That is, unless you interrupt rabies
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long strange trip [music] before it's
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able to make much headway toward the
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brain. The disease moves so slowly that
2:45
you can get vaccinated even after you
2:47
get infected, because [music] there's
2:49
still enough time to train your body to
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recognize and fight off the disease. The
2:54
only way to survive rabies is to control
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it before it controls you.
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>> [music]
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[music]
