Why is it so hard to cure rabies?
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Medicine still struggles with ‘curing” viruses directly. Our big trick is usually to do something immune system related and then have that deal with it. We have a rabies vaccine but once you have it we don’t have tons to actually fight the virus.
The other big thing is the way you deal with a bad virus is make the person survive it. If you have a lung virus you put the person on oxygen until the virus passes and the lungs heal, if someone has a digestive virus you feed them through a tube or IV until their digestive system heals. Etc. Even if a virus destroyed your whole heart you might get a heart transplant. But rabies kills your nerves and your brain. We could keep someone with rabies on a machine as long as we wanted, but what are we gonna do? Wait until their whole brain grows back? It breaks too much irreplaceable stuff too fast to ever recover at all once it’s done damage.
If you get treated fast enough the body can handle it. Like tetanus, by the time you are seeing symptoms that means there is irreparable damage and it’s too late to start treatment.
The short answer is because it can cross the blood-brain barrier.
In your head there’s a semi-permeable barrier that selectively allows certain necessary things to cross from the bloodstream to the brain’s cerebrospinal fluid. It’s a very selective barrier. Over 98% of our small molecule drugs can’t make it through this barrier which dramatically reduces our ability to find therapeutics which can do the job because what antiviral molecules we do have (and we have very few of them) are typically relatively huge compared to what can cross the BBB.
The rabies virus, however, can cross it. It does this by infecting the cells that make up the endothelium of the blood-brain barrier and then releasing the virus into the CSF on the other side of it. Once that happens death is almost certain since we don’t have any drugs that can get to the other side to help fight against it, even if we did have a drug with an anti-viral effect against rabies.
Why aren’t we looking for a drug with an anti-viral effect against rabies? Because a post-exposure rabies shot and/or human rabies immunoglobulin is almost 100% effective when given in a timely manner.
I believe because by the time you know it’s rabies it has progressed past the point of treatment.
We can treat rabies. It’s the damage it does that we can’t fix.
If you start to show symptoms, your brain is already damaged. If we could cure that, then there’s a lot of other injuries we could fix too, but it’s beyond our abilities, at least at the moment. You need to be treated for rabies as soon as you think you’ve been exposed before any damage has been done.
Your body can cure itself of rabies, if it notices that it’s been infected with rabies. The problem is that it doesn’t recognize rabies as a threat and the. You die. The rabies vaccine can jump start the response. You can even get the vaccination shot AFTER you’ve been infected by rabies! It will inform your immune system that a rabies infection is under way and it will kill off the virus.
Ironically you can survive rabies if it doesn’t kill you! Lol, sounds stupid but that’s how it is. Survive long enough and your body will defeat it. But that’s a problem.
We do it all the time when you hear people getting rabies shots immediately after they are bitten. The problem is that if you wait for symptoms to show, the disease has already progressed so far that you’re most likely going to die.
Think of having cancer, but there are no symptoms until it’s late stage and fatal.
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