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The Weird Reason Rabies Is So Deadly
The Weird Reason Rabies Is So Deadly
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Subtitle (90)
0:00
Rabies is one of the deadliest [music]
0:02
diseases we know of. If you don't get
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treatment soon after getting exposed,
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you are almost [music] certain to die.
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But rabies intent isn't actually to
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kill,
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>> [music]
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>> it's to control. Hi, I'm Kate and this
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is MinuteEarth. Pathogens have one goal,
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to replicate and spread to new hosts.
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And they use all kinds of creative
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strategies [music]
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to accomplish that goal, like inducing a
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poop-tacular amount of diarrhea, or
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making their hosts sneeze or cough all
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over the place, or causing [music]
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oozing germ-filled sores. We made a
0:33
video all about this. But most of these
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strategies [music] share the same
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general approach, cause physical changes
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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
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in the host to make transmission more
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likely. Rabies is transmitted through
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[music] saliva. In order to infect a new
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host, that virus-laden saliva needs to
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make its way into a different critter's
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body.
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>> [music]
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>> Once it's in there, unlike most
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pathogens which move through the
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bloodstream, rabies viruses travel
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through [music] their host's nerves.
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It's not a fast way to travel. The
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viruses only advance a few inches
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[music] a day, but it helps hide them
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from the host's immune system, and it's
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a direct route to [music] rabies desired
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destination, the brain. There, the
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viruses start to build up. Scientists
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[music] don't totally understand the
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details, but the viruses seem to bind to
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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
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case in animals like dogs and bats.
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Humans infected with rabies sometimes do
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act differently. [music]
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They may get agitated and anxious, but
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they don't go around biting people.
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Probably because, unlike rabies normal
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hosts, [music] humans instincts to bite
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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]
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And uh speaking of dead, the clever way
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that rabies tries to ensure its
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transmission by interrupting the brain's
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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
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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,
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[music]
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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
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you can get vaccinated even after you
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get infected, because [music] there's
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still enough time to train your body to
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recognize and fight off the disease. The
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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]
