I’ve never quite understood this, I know that it’s not really a priority to solve due to us vaccinating animals who might be vectors, but what makes it so deadly for the people who do contract it?
I’ve never quite understood this, I know that it’s not really a priority to solve due to us vaccinating animals who might be vectors, but what makes it so deadly for the people who do contract it?
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It moves slow and goes for the brain through your nerves.
Once it gets to the brain there really isn’t anything people can do. If the symptoms start, its in your brain.
Basically it infects your neural pathways and your brain, which don’t have an immune response to it. There’s just nothing your body can do as it melts your brain into mush.
The upside is that it travels so slowly (depending on infection site) that’s it’s about the only disease you can get a shot for AFTER being infected and have the immunization work. There is enough time for your immune system to figure out antibodies from the shots to them turn around and use them on the active infection.
Theres a good YT video on it: https://youtu.be/4u5I8GYB79Y?si=ijRu3U3ecjIIAfJ0
Small edit: I rewatched the video and basically it just sneaks by your immune response on the way to the brain. And once there and symptoms exhibit, it doesn’t have a fatality rate near 100%. Without medical treatment, it has a fatality rate of 100%. There have only been a few people who have survived rabies without the vaccine and that is with drastic medical intervention.
Rabies attacks the central nervous system and is incurable and untreatable once symptoms start. It causes paralysis, confusion, aggressive behavior. Those afflicted become hydrophobic and cannot drink. Eventually the body can’t perform the most basic actions necessary for survival. It kills the parts of you responsible for moving your meat mech and reminding it to do things like eat, drink, breathe, pump blood.
It doesn’t. If you get vaccinated early, it’s very treatable. But once you get symptoms…
Rabies is a neurological virus that gets into your brain by traveling up your periphery nervous system. It travels very slowly because it can only hop nerve-to-nerve. So if you think you got bit and you get a vaccine, your immune system can head off the virus before it gets all the way up your nervous system and you get away okay (minus side-effects).
If you have symptoms, it’s because the virus is doing damage to your brain. Once things progress to that point, odds of survival are poor; your own immune system is highly restricted against attacking things in your brain (most of the tools your immune system uses against viruses involve killing the host cell; that’s fine if the cell is a replaceable liver cell, but not so hot if it’s where your brain keeps your piano lessons or, say, your swallowing reflex), so the virus gets to grow with very poor defense against that growth.
What makes it so deadly is that it attacks your brain and spinal cord. The virus is then protected by the body’s own blood-brain barrier and medication has a hard time reaching it, compounded by the fact there is no current medication at all to treat it.
Eventually the attacks on the brain/sc leads to the patient falling into a coma, then respiratory and/or cardiac arrest. So you’re on an unstoppable path to your brain and spinal cord, and thus your heart and lungs, no longer being able to work.
Slow moving viruses with no early symptoms are harder to detect. By the time you have symptoms, it’s too late. This is why you always get the rabies vaccine right after you have been bitten if there is suspected exposure. The vaccine will work if given shortly after exposure (because the virus moves so slow).
By the time you have symptoms, its too late.
Also, you can get infected without knowing it as one of the main carriers has bite marks that are small enough to not leave a mark. You think something flew by you, but it actually bit you, and you dont notice. Even if you do, you need to see a doctor and bring up the story — and most people are terrible about seeing a doctor about anything let alone in a timely manner.
There’s something called the blood brain barrier. This barrier makes it hard for things to pass through on most occasions. Rabies is one of the rare things that can cross the blood brain barrier. The issue is once it’s in the brain we can’t get medicine in there to fix the issue because nothing we have can make it into the brain to get to the rabies. Since the meds can’t get in rabies is usually fatal.
Rabies attacks the brain. You need your brain to live, and eventually you die because your brain gets destroyed. One reason it must be treated before it becomes symptomatic is that few drugs can cross the blood-brain barrier, so once it becomes symptomatic there’s no way to treat it. It also evades the cells which signal infection to the rest of your immune system:
>The antigen-presenting cells, such as the dendritic cells, fail to pick up the traces of the virus and present them to innate and adaptive immune cells to clear the infection.
It is also immune to antivirals used for other viral infections:
>Most viral infections are vulnerable to antiviral drugs, which operate by inhibiting the viral lifecycle that is essential to productive infection. However, the rabies virus is adept at evading these antivirals as well as the host immune response.
https://www.news-medical.net/health/Why-is-the-Rabies-CFR-So-High.aspx
because the virus travel through nerve toward the brain. And the brain is one of the few immune privileged area, like eye iris and sex cells. Since normal immune response will cause too much inflammation and damage these heat sensitive cell. But the trade off is once virus get into these immune privileged area, the immune response is weaker and allow any viral intruder to wreck havoc.
Well, to be perfectly accurate, rabies doesn’t have a near 100% fatality rate. It’s only once a patient has developed symptoms that the fatality rate goes up that high, and that’s because the symptoms don’t appear until it’s entered the brain and central nervous system.
A person’s immune system doesn’t have free access to those parts of the body because it can do more harm than good there, and any outside treatment also has a very good chance of doing fatal damage there. So once it gets to that point the patient is pretty much out of luck.
Also, how is a 100% fatality rate a good survival strategy for the virus?
The long answer is… complicated.
The short answer is that rabies is caused by a lyssavirus. That virus is similar to other mononegavirales (think virus class) like ebola, measles, mumps, and a few others.
There are a bunch of ways to be exposed to it that allow the virus to proliferate but the most common way is getting bitten or scratched by an infected animal. Because the virus attacks the nervous system, it can be very hard to detect early on and is often asymptomatic, sometimes for up to a year or longer. This makes it harder too in that the specific symptoms seen early are nonspecific, IE a fever or muscle aches that most people end up assuming they have a cold or something similar.
I won’t get into the complicated mechanism of action for the disease but the short version is that it causes encephalopathy (swelling of the brain) that becomes nearly impossible to correct once the onset of neurological symptoms develop.
There have been a couple of cases of people surviving after that but they were put in drug induced comas for a long enough period to let the encephalopathy subside and to my knowledge nobody has survived it without serious long term effects from the brain damage.
All in all the biggest take away is there is a vaccine for it, and you should talk to your doctor if it’s right for you, and definitely don’t go playing with any stray animals, because confirming testing of the disease involves capturing the infected animal and cutting his head off for biopsy to confirm. Let the wildlife be wildlife.
Soooo rabies is a complicated one. The virus travels from the site of infection to your brain, which is where it starts (for lack of a better term) fucking shit up. Rabies incubates silently so there will be no noticeable symptoms until it is too late which you probably know. The reason it is “too late” is because by the time enough damage has been done to cause symptoms, the virus has also effectively changed the make up of the membranes between the rest of your body and your brain to make it so that medications that would neutralize the virus cannot pass through. It has essentially invisibly barricaded itself.
HOWEVER, the virus isn’t particularly resilient and also takes quite a long time to get to its target. This is why post exposure vaccination is almost 100% effective. The shortest incubation time ever recorded was 5 days but this is incredibly difficult to know exactly because it is impossible to get accurate history from confirmed rabies victims due to the nature of the symptoms. Generally there is a period of 30-90 days to bulk up your immune system in order to knock the virus out before it can even get close to the point of no return.
It absolutely is a priority to try and establish some type of treatment that could actually stop rabies once it already started to manifest, but given that is so challenging for the reasons I described, public health professionals are better off focusing on removing it from animal populations through vaccination and making post exposure treatment available. Human to human transmission is virtually unheard of in modern times except in a couple very rare and scary cases of organ transfer. Also it is hard to work with because the virus is so dangerous and the biohazard protocols make research really difficult.
This description always frightens the hell out of me – basically how you might only know when it’s too late: https://www.reddit.com/r/copypasta/s/7lSVUdSldv
What a lot of people aren’t mentioning is why we can’t treat it once it’s in the brain: our bodies have a pretty hard barrier between the brain and everything else. This is usually really helpful to avoid infection, autoimmune responses, etc. but it also prevents most forms of medicine from acting. You have to directly put the medicine in the brain otherwise it won’t work, and developing medicine that works and also doesn’t destroy the brain in the process is pretty much impossible.
Edit: https://en.m.wikipedia.org/wiki/Blood–brain_barrier
There are some studies showing neutralizing antibody titers in unvaccinated humans and dogs.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7017994/#:~:text=For%20example%2C%20in%20a%20study,exposure%20regularly%20occurs%20%5B15%5D.
Suggesting there could be low level exposures that don’t lead to infection or possibly naturally immune individuals.
PSA – don’t mess with rabies, get vaccinated if exposed.
It breaches the blood brain barrier.
Even our own anti bodies can’t do that. So once they’re in, there’s no getting it out.
Viruses are like robots with one job: make more robots. They make more viruses by invading your body, taking parts of it over, and then using those parts to make more robots.
Your body doesn’t like this and produces its own robots to fight the bad robots. When the good robots find bad robots they call up lots of their buddies, and even make new ones, so they can all gang up and kill the bad robots.
Most viruses are pretty loud and clumsy. They invade, take over their favorite neighborhood, and then start wrecking the place. This is really noticeable, and your body sends lots of good robots to kill the bad robots. All the mess and fighting still make you sick, but most of the time the good robots win and you get better.
Rabies virus is like an evil ninja robot. It sneaks in and is really good at hiding. It likes a very specific neighborhood to invade, your central nervous system and brain, the parts of your body that control all the other parts.
Your brain is very important right? So the body has erected very high walls around it so the bad robots can’t get in. In fact, the walls are so high even the good robots can’t get in.
The rabies ninja-robots are special and can climb those walls no matter how high they are. They don’t start making a mess until they’re inside, and even though they’re making a really bad, loud mess the good robots can’t get inside to fight them. The bad robots get to keep making more and more bad robots until they wreck all that important stuff – like your brain – and you die.