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Rabies is absolutely horrifying. Some would even go as far as to say that it creates
literal zombies and in today's video, we're going to use the cadavers to take a look at the various
organs and tissues that are affected by the rabies virus as well as discuss the many symptoms
associated with it. This is going to be a scary one. Let's do this.
Let's start off by discussing what rabies even is in the first place. Now, rabies is
going to translate to madness or rage which is pretty telling about what this is capable of
but rabies is a disease that is going to be typically caused by the rabies virus. Although,
it can be caused by other viruses but regardless of the virus, those are all going
to be examples of what are called Lyssaviruses and "Lyssa" is going to translate to violent
which again is going to be pretty telling about what this is capable of but rabies today is
capable of killing anywhere between 50 and 70,000 individuals worldwide per year and it's an example
of what's called a zooinotic disease, meaning that it's transmitted from animals to humans.
Although there have been some cases of direct human to human transmission,
they're going to be extremely rare but it happens in things such as
organ transplants which is absolutely terrifying to think about but by far
and large, it's going to be transmitted from animals to humans and specific for mammals.
So this is going to be transmitted or capable of being transmitted from things like cows, bats are
a very big one, dogs, cats, literally if it's a mammal, it's capable of transmitting rabies.
The rabies virus is what is called neurotropic. Meaning that it is
specifically adapted to attack the nervous system.
It can and does attack other tissues in the body but it's specifically there to attack the
nervous system. And that actually plays a pretty big role into why it's so difficult to treat.
And when say difficult? I mean difficult. There have only been a handful of people
who have survived the infection once symptoms start to show up. That's why you'll commonly
see it be described as being 100% fatal if you - if one symptoms start showing up.
However, if you get treated in time, that's typically within 10 days of being bit by
an infected animal, it's 100% preventable disease. So, it's either 100% preventable,
you're going to be fine or 100% fatal and you're going to die. So those - that's
both of the - I feel like I understand which option I would personally like.
Now, I do need to mention its incubation period. That's basically the time
frame that it takes from being bit until when symptoms start to show up and then you die
and it's typically around one to three months.
However, there have been cases where people have started to display symptoms
just a few days after being bit and then there are other cases where it's taken
multiple years. In preparation for this video, I stumbled upon a case study of
an individual who had bitten - been bit by a dog eight years previously and then died.
When the doctors started looking into the specific type of virus that caused his rabies, they
discovered that it was only found or usually found in dogs in Brazil and so they asked his family,
"Has he ever been to Brazil" and they said, "yes". He went to Brazil and got bit by a dog eight years
ago which means that the virus was just kind of sitting in there in his body and then,
it finally made its way into his nervous system and killed him which is absolutely horrifying.
So, what we're going to do now is we're actually going to take a look
at the cadavers and we're going to kind of follow. We're going to say, if you get bit,
we're going to follow the virus as it starts to make its way and propagate
through your body. So, let's go ahead and jump on over to a cadaver.
You are looking at a left arm that has been cut mid brachium. So,
this right here is going to be the humerus and you can see like biceps brachii here and
then you can see all of the antebrachial muscles or forearm muscles. So, let's go ahead and say
that you get bit by a rabid dog in the arm and so, the - as it punctures into the muscle tissue,
it's going to be delivering the virus into the muscle tissue.
Now, remember, the rabies virus is not adapted
to replicate very easily in muscle tissue. What it's really going to be going for, I'm gonna
open this up here, is nervous tissue like this. This is the ulnar nerve.
You can also see it kind of branching off right here and then, we also have the median nerve.
So, the target base on this bite location is going to be these nerves. One of these nerves or both
of these nerves. Now, you have to understand, that there are going to be countless offshoots
that are going to be permeating the muscle tissue to make these - all these muscles work.
So, the virus is going to be replicating very slowly inside of the muscle tissue
and this is one reason why it can take so long for you to display symptoms but as soon as it
gets into the nervous system, that's when you can start feeling numbness and tingling that area.
So, if you ever get bit by a rabid dog or any kind of animal and you start feeling numbness
and tingling in the area, that is a sign that the virus is starting to make its way
into the nervous system and you also might start displaying a fever and a headache. So, you might
start feeling fluish. This is your body trying to mount some kind of defense against the virus.
Those are all very strong signs that you have or you could potentially develop the rabie - rabies
disease. So, now the what going to start happening is the virus is going to - let's go back here,
is going to start traveling in a retrograde
direction. Sorry, let me get this here and it's going to start traveling
up the nerve and it's going to start making its way up this nerve until it's eventually going
to get to the spinal cord and the spinal cord is going to be part of the central nervous system.
So, let's go ahead and jump on over to a different cadaver and check that out. Let's go
ahead and orient you because it might be a little difficult to understand what you're looking at
these bones here. These are going to belong to your cervical spine so you're looking at the neck.
This is the front of the neck right here, then we have the back of the head,
back of the neck right there, this is going to be the tongue
then we have the roof of the mouth and then this, all this tissue here these are part of
the meningal system - this would wrap the brain which we've removed - the brain would be located
right there but what I want to focus on is going to be this tissue here. This is the spine cord.
Now, the spinal cord belongs to the central nervous system with the brain and that's
because they're running down the center of your body like literally central nervous system. Now,
it's going to then branch out into the peripheral nervous system which we just saw. That was like
the median and the ulnar nerves, but this spinal cord is going to be running
basically from the bottom of your head all the way down to your first and second lumbar vertebrae.
Now, let's go ahead and understand that once the virus gets into the spinal cord,
it has a straight shot to the brain. The spinal cord is essentially a highway of neurons
travelling to and from the brain going down the torso.
So, once the virus gets in there, it's just able to go directly up to the brain.
Now, we should take a brief moment to discuss the location of the bite and how that can influence
you because let's say you get bit in a toe as opposed to getting bit in the arm. Well,
that's actually going to take longer for the virus to get up to the brain
so you're going to have a incubation period because it's going to have to get into the
muscles, get into the nerves, go up to the spinal cord, go up the entire length of spinal cord
as supposed to just right up there or let's say you get bit in the neck or the face.
The closer you get bit to the brain,
the faster that virus is going to be able to get to the brain. So,
with that said, let's jump on over to a brain and discuss what happens when the virus gets there.
You are looking at both hemispheres of the human cerebrum and I say cerebrum because
we've removed the cerebellum and brain stem from down below You're also going to notice
that there is some damage to the brain. This brain was removed by a student of
ours during a dissection course but all things considered, I think she did a phenomenal job.
Now, you're also going to notice there is a separation between the left and right hemispheres.
This is called the longitudinal fissure and then, you're also going to see a ton
of amazing blood vessels embedded inside of the meningial tissue on the surface of the brain.
Now, if you look closely, see this spot here, that's the actual color of the brain tissue
underneath meningial vessels and meningial tissue. So, if we removed this layer here,
it would look more like that spot but once the rabies virus gets to the brain itself,
this is where it starts dividing like crazy.
Remember, it's neurotropic. So, it's designed to attack and thrive and replicate in this brain
tissue. So, it's going to start dividing like crazy and that's going to cause the
brain to swell up, right? The brain is going to start expanding and pressing against the skull
and this going to start creating a whole variety of symptoms
and these are the symptoms that you probably think of when you're thinking of rabies.
So, things like anxiety, insomnia, aggression, but it doesn't always have to be aggression or
agitation, it also could be paralysis. In some individuals, they get what's called a paralytic
form of rabies where they just become paralyzed but in most cases, they do become agitated. They
can - you start getting twitching and just sometimes violent movements but when I say
"aggression", there's this - there's this thinking that this aggression is going to be just like
they're going to attack other individuals - that can happen but it's not as though it's
just this relentless zombie type of attack. In reality, it could just be an outburst of violence.
I'm not saying that's really better but at the same time, I don't want you to think that they're
just completely hyper aggressive at all times but you're definitely going to get that. Now,
the next thing that's going to happen is the virus is going to start pushing out of the brain and as
it starts pushing out of the brain because once it gets there and it starts to biting like crazy,
it's now going to start pushing back out the peripheral nervous system
and it goes to the organs. It starts going all throughout the body.
It's at this stage you could also start getting nausea and vomiting with that infection but
this is when you're then going to slip into a coma shortly after this and then you are going
to die and death typically occurs around two to 10 days after symptoms onset and again, it just
really depends on view and a couple different factors but this is a very fast-acting virus.
Once it gets into you, it's replicating very quickly which is one reason why it's so difficult
to treat and you want to do this right away because once it starts dividing, there's really
not much you can do but the virus is going to want to be transmitted to its next host. It
doesn't want to just die with you and that's where it's going to make its way to the salivary glands.
So, let's go ahead and jump on over to another cadaver to section and check those out.
Once again, I want to orient you so you understand exactly what you're looking at here
this is going to be the trachea or your windpipe. This is the thyroid gland. If I scoop this muscle
to the side - this is your voice box or your larynx and that makes this part of the tongue
that has been cut and then you can see the back of the throat or part of the pharynx
but what we really want to focus on is going to be this thing right here.
This is called the submandibular salivary gland and if you also look closely, hopefully we can see
this, there are ducts and what's going to happen is that submandibular salivary gland is going to
be secreting saliva through the ducts which will then empty into the oral cavity and the pharynx
and that's going to be important for digestion but for rabies, what's going to happen
is once the virus is pushing out of the brain, it's going to start going to this
salivary gland as well as a few others because you do have other salivary glands
and it's going to cause them to start hyper secreting saliva.
So, saliva is just pouring and emptying into your oral cavity and mouth And this is again because
the virus wants to be transmitted to its next host. Remember one of the symptoms was aggression.
Now, in four legged creatures and mammals, one of their most effective defense mechanisms is
to bite. So this makes complete sense because then what will happen is they're foaming at the mouth.
They're hypersalivating filled with virus and then - and then they want to bite. And as they do that
then you can then transmit that virus to the next host.
For human beings, biting is not really all that common. I don't know about you, but I mean
like - it's not my go-to defense mechanism. Sure, biting can happen during a fight or
something along those lines but it's not your go to and that's because just humans, we don't attack
with our faces like a lot of other creatures do on this planet which is one reason why biting
is not actually seem to be a symptom, a common symptom in rabies patients for human beings.
Does it happen? Absolutely and you'll hear stories from facilities that are designed to treat rabies
patients where they have to do padded rooms, lock them in there, or possibly even tie down
the patients to prevent them from biting but it's not common enough to be said to - for it to said
to be a common symptom. It's not something that you are guaranteed to have happen which is a
little strange because you - when you think of rabies, you think of a raccoon. You think of a
dog. You think of them biting and transmitting it but for humans, it's just not an effective
mode of transmission but regardless, the virus is still to be going to the salivary glands and
causing that hypersalivation in an attempt for that to happen but you also have to understand
that the pharynx which I'm touching palpating right here and the esophagus are also going to
start spasming violently closed and they do that because they don't - basically the virus does not
want the saliva to go down your esophagus and go into your digestive tract because it dilutes it.
It wants to be as potent as possible. So, it literally closing off and what that's this helps
to create is what's called hydrophobia. Rabies patients and rabies - and animals infected with
rabies display a fear of water because think about it - by drinking the water it would dilute the
virus. So when you actually bring water close to a rabies patient, they will pull away. They can even
get violent with that pulling away because what will happen is the pharynx and the esophagus will
start spasming and it's extremely painful. So they display this fear of water. Absolutely terrifying.
So is it a zombie virus? I don't think I'd go that far. Mainly because
most patients aren't going to be biting like crazy. They may be aggressive but
even that aggression is not relentless type of aggression that you would see in a zombie.
It's more sporadic and they can have violent outbursts but it's not as though
they are just like chasing you down and trying to eat you or anything like that.
There's definite similarities to what you - I mean a quote unquote "zombie"
but I still wouldn't go as far as say it's that you're actually turning into a zombie.
I think there's a lot of hype around the severity of rabies when you compare that
to a zombie which is why you hear that a lot but in my personal estimation,
I don't think it quite classifies as zombie virus despite being absolutely horrifying.
There are plenty of other pathogens and diseases equally terrifying as rabies.
However, filtering through the hype and coming to a realistic expectation
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off their annual subscription. Thanks for watching everybody and I'll see you in the next video.