Halloween season wouldn’t be what it is without the undead.
And some might say the most spine-chilling creature of that realm is the vampire.
(Splash)
Welcome to this week’s episode of Reactions, where if today’s sinister being doesn’t
scare you, the chemistry behind how it came to be just might.
When you think “vampire” some of today’s most popular vampires might come to mind.
Attractive bloodsuckers with pale, sometimes sparkling skin.
But in the 18th and 19th centuries, when European vampire lore first really took off, they were
a bit more...morose and, instead of that crystal-clear skin, they appeared kind of sickly with a
reddish complexion.
Vampires were often depicted as men from poor, rural areas, who, after dying--often from
diseases like the plague--would emerge from their coffins to wreak havoc on a nearby town,
sucking the blood of humans, turning them into vampires as well.
So how did this folklore come about?
Possibly...disease.
Diseases that gave sufferers symptoms strikingly similar to what we see in vampires--things
like pale skin, sensitivity to light, and a predilection for...biting.
Most would say these connections are...speculative, since medical records from hundreds of years
ago were non-existent or questionable at best, but they’re still fun to think about on
a lonely winter’s eve, with some fava beans and a nice chianti.
Let’s examine a few of our blood-sucking friends’ most famous traits.
First, a constellation of vampiric symptoms: Weakness and exhaustion, fangs dripping with
blood, an aversion to garlic, and sensitivity to light.
A disease called congenital erythropoietic porphyria, or CEP, causes many of these and--interesting
side note--it’s a disease that’s also linked to werewolf lore, but we’ll have
to tackle that another time.
CEP is a rare disorder caused by a defect in genes related to, appropriately enough,
your blood.
People with CEP don’t make as much heme--an iron-containing molecule that makes it possible
for your blood to carry oxygen.
This causes their red blood cells to break down, decreasing their red blood cell count
which, at the very least, would make them feel exhausted.
That takes care of one symptom.
When you’re not creating heme, toxic compounds called porphyrins build up.
That’s because heme is derived from these compounds, which get their name from the Greek
word for purple.
When you're not creating heme, these deep reddish purple porphyrins build up in your
bones... and in your teeth, creating a look reminiscent of blood-covered fangs.
What about garlic?
This one is a bit more tenuous.
Certain compounds in garlic can increase activity of an enzyme called heme oxygenase-1.
Heme oxygenase-1 breaks down heme.
And remember, if you have CEP, your levels of heme are already extremely low.
The last thing you would want to do is eat something that reduced them further.
However, this doesn’t fully explain why vampires would be afraid of garlic.
To affect them, they would have to eat it.
And finally, the Sun.
Folklore is definitely split on this one but most vampires seem to want to avoid the sun
at all costs.
Turns out, CEP may be able to explain that too.
In people with CEP, the Sun can be dangerous.
It causes porphyrins to donate their electrons to oxygen, and--with the help of an enzyme
called superoxide dismutase--form reactive oxygen species like hydrogen peroxide, which
can destroy your cells and cause severe skin damage.
And I mean severe, in some cases so much scarring that it leads to a loss of facial features.
Now, let us take a brief historical tangent.
Because CEP is a rare genetic disorder you may be wondering--if it’s so rare, how could
it have inspired vampire folklore?
Well it might not have always been so rare.
Why?
Because of inbreeding.
In the past, inbreeding--which was especially common among royal families--brought to the
surface diseases you wouldn’t normally see.
In other words, we would counsel against marrying thy cousins.
Back to vampires.
There was another disease that caused people to shun the Sun: pellagra.
Pellagra is usually caused by insufficient vitamin B3 -- also known as niacin, which
can be synthesized from the amino acid tryptophan or found in most meats, and foods like brown
rice, sweet potatoes and peas.
Being sensitive to the sun is a hallmark of this disease, but why still isn’t entirely
understood.
One might say we’re… in the dark… on this one.
But perhaps the most famous trait of all...a proclivity to bite and consume copious amounts
of blood.
There’s no well-defined disease that makes people drink blood, but there is a disease
that causes infected creatures to bite: rabies.
To this day, rabies claims the lives of tens of thousands of people each year.
And its symptoms are, in my opinion, more terrifying than the thought of being face-to-face
with a vampire.
In addition to fatigue, fever, and intermittent spells of panic, rabies can cause aggression--which
includes biting--hallucinations...seizures...coma and...death.
Rabies is a virus that’s transmitted through saliva when an infected animal bites or scratches
their victim.
Rabies will ruthlessly hijack a newly infected animal’s brain, and when it does it often
makes them bite.
How the virus has this power isn’t entirely clear, but it’s an unbelievably clever way
for it to spread to as many beings as possible.
Once rabies infects your cells, the virus will quickly travel to your spinal cord and
brain, where it multiplies, all the while ravaging your cells.
It then moves on to your salivary glands and, ultimately, saliva.
Rabies can lay dormant for months, but once you begin to show signs of infection, death
is already knocking--most people then die within a week.
If left untreated, rabies is fatal almost 100% of the time.
Other vampiric symptoms from rabies include a fear of water, a fear of mirrors, and insomnia.
While less common, when a person with rabies sees water or their reflection in a mirror
their larynx might spasm.
Sometimes this causes their esophagus to tear, making them cough up blood.
Vampires mostly wreak havoc at night, and people with rabies aren’t exactly known
for sleeping.
Rabies damages your brain cells and causes your brain to swell, and that will affect
regions of your brain that, in part, control sleep.
Centuries ago, when vampire folklore took flight, many of the resources we have now--like
foods that provide niacin, or a rabies vaccine--weren’t as readily available, or just didn’t exist.
And maybe you’re wondering, what about other vampire-esq traits?
Like blood dripping from a vampire’s mouth?
Or a belly full of blood after a night of feasting?
Some have speculated that people created that lore after looking at corpses that were naturally
decomposing.
When someone dies, blood can leach around the sides of their mouth, and gas can accumulate
in their intestines, causing their stomach area to swell.
Didn’t show that in Twilight.
We want to say a big thank you to Dr. Emily Zarka for advising us on some of the vampire
lore for this video.
For more monsters, check out her PBS Digital Studios series Monstrum, which we’ve included
a link to in the description below.
Are there other undead beings that you think may hold some interesting chemistry?
Let us know in the comments and we’ll see you next week.