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I'm still not sure about the mechanics that lead to rabies being incurable. I know that it can be treated before any symptoms show up, but why is it that once symptoms show the person is a dead man walking?

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I understand what you are asking, but I think the wording is a bit odd. There is not a mechanism that renders rabies uncurable. We simply have not managed to create a cure yet. –  nico Apr 12 '12 at 16:23

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This is because rabies is a viral infection of nervous tissue that propagates through peripheral nerves into the brain and causes brain tissue inflammation (encephalitis).

As long as the virus is in the brain there is no way to get rid of it. The main trade-off here is that everything that would kill the virus will be as (or even more) aggressive against the brain tissue, and impairment of the latter will lead to really heavy deficits in vital functions like breathing and thermoregulation.

The first manifestations of rabies are those due to brain damage. This means, the virus is already there and the brain is already fatally damaged.

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Ok, so the virus is already in the brain tissue if treatment isn't started. Thank you. –  Robinabo Apr 12 '12 at 16:42
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@Robinabo - Well not exactly. The virus starts out infecting peripheral nerves, and takes advantage of the transport mechanisms to be transported up the PNS toward the CNS until it gets to the brain. You have a very limited window to receive treatment (anti-rabies vaccine). Once a human is symptomatic, odds of survival drop precipitously toward 0% (there are only one or two cases of humans that have survived a symptomatic infection). –  leonardo Apr 12 '12 at 23:37

It may actually be curable, as shown by success stories involving the Milwaukee protocol in which the brain is effectively shut down to allow for the immune system to eradicate the virus. In most cases, however, it is fatal once symptomatic. Note that the Milwaukee protocol boasts an imporessive (sarcastic) survival rate of under 15%

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Interesting! But I can't see it being adopted with <15% survival (although this is better than 0% if no treatment is administered)! But work will undoubtedly continue. –  Luke Aug 21 '12 at 8:05
    
Also, even if you survive, you'll likely still have suffered permanent brain damage. –  Mechanical snail Sep 16 '12 at 4:49
    
It's a small price to pay, in most cases. –  Snakes and Coffee Sep 16 '12 at 6:43

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