The animal kingdom is full of terrifying and deadly parasites.
While there aren’t any that will eat their way out of a human’s chest - unlike those
a certain sci-fi movie makes us afraid of - there are no shortage of parasitic animals
that would love nothing more than to feed on you.
These are the thirteen most painful parasites that infect humans.
#13.
Tapeworms
One of the most common parasites, tapeworms usually make their way inside the human body
as hitchikers alongside your lunch or dinner.
These tiny, ribbon-like worms lurk inside the flesh of animals, commonly fish, beef,
or pork.
When you unwittingly consume them, these creatures don’t get digested - they set up camp in
the digestive tract and can live there for a long time.
Their long bodies have hooks or suckers that embed themselves in the intestine, and they
then get all the energy they need to live by absorbing part of your food.
But they don’t stay invisible for long.
People who are infected with tapeworms soon report symptoms including nausea, vomiting,
digestive issues, unexplained weight loss, and signs of malnutrition including dizziness.
While most people eventually expel their tapeworm through their digestive tract - which can
be a disgusting sight in the bathroom - they can survive for up to twenty-five years.
And when ingested as eggs or larvae, the tapeworm can reproduce in the body.
Larvae can turn into cysts that migrate through the body - even in the brain, where they can
potentially cause serious illness or even death.
This parasite is often invisible - but the next makes itself very well known.
#12.
Bedbugs
These little insects are the scourge of anyone who has stayed in a hotel.
Tiny bloodsucking insects that are notoriously hard to find and eliminate, they spread in
high-density areas and can hide in mattress seams or wall cracks.
When they attach to a person, their bites cause a host of skin issues that become impossible
to ignore.
Skin rashes, blisters, and constant itchiness become a part of regular life until the bedbugs
are eliminated, and more severe cases can result in fatigue and fever.
While the insects aren’t known to spread serious diseases - unlike other pesky bloodsucking
insects - one of their biggest threats is causing allergic reactions.
And while many exterminators will promise to get rid of a bedbug infestation, these
little buggers can live up to seventy days without feeding and reproduce fast - making
them likely to be unwelcome guests for a long time.
These next parasites make their presence known in a very unpleasant way.
#11.
Pinworms
Roundworms are a common species of parasitic worm that lays eggs in the body, but many
of them don’t pose a serious danger to humans.
That’s not to say you don’t want to avoid them - especially the pinworm, a small worm
that spreads via its eggs.
It can be picked up via contact with the hands and then getting swallowed - and then it goes
where the sun doesn’t shine.
The pinworm likes to lay its eggs around the anus, and this causes a host of uncomfortable
symptoms for the unlucky humans.
Pinworm hosts report itching around the anus, painful bowel movements, and difficulty sleeping
due to the constant annoyance.
Fortunately, it can be treated with a number of medications - but the worms spread so quickly
that doctors recommend everyone who lives with the infected take the medicines.
This parasite is so common that it’s estimated that twenty percent of children in the United
States will get infected.
Some roundworms, though, can cause much more serious infections.
#10.
Filarial Worms
Everyone knows mosquitos are annoying, but some can carry something far more dangerous.
These pesky bloodsuckers are hosts to tiny roundworms that can cause a whole host of
diseases.
Mosquitos are a common transmitter of plague, and the World Health Organization estimates
more than 120 million people may have an infection of filarial worms.
While many of them don’t cause any symptoms at all, they have the nasty effect of clogging
lymphatic vessels in some cases.
Another variety affects the eyes.
These worms can usually be treated with antiparasitic medications, but if left untreated they can
cause serious ailments.
They’re one of the world’s leading causes of blindness, and in severe cases can cause
elephantiasis syndrome - a disorder that causes extreme swelling due to the inability of the
lymph glands to drain, mostly affecting the legs.
The next parasitic worm has more aggressive tastes.
#9.
Hookworm
The Hookworm is a species of roundworm that is common in many countries around the world
- especially those without access to clean water.
Its larvae infects people both orally and through the skin, at which points it sets
up camp inside the human digestive tract for a feast.
Pretty similar to other parasitic worms - except the hookworm doesn’t want your food.
It wants your blood.
These worms latch onto the intestinal tract and start acting like a vampire, causing major
health issues for the unfortunate host.
If left untreated, it can cause abdominal pain, nausea, diarrhea, and most seriously
anemia that can result in weakness and other serious health conditions.
This worm kills up to 60,000 people a year.
The good news is, it’s vulnerable to many anti-parasitic medications, but it’s hard
to detect before it reaches maturity.
But it’s not the most deadly parasitic worm.
#8.
Whipworm
The whipworm is a soil-based parasite that infects over half a billion people worldwide,
and is mostly spread by contaminated soil and often eaten through fruits and vegetables.
The eggs hatch and take up residence in the large intestine.
While many cases are asymptomatic, those who have heavy infections can find themselves
seriously sick.
Not only do these worms wreak havoc on the digestive tract, but it can trigger more serious
illnesses like appendicitis that require emergency surgery.
Its most dangerous effect, though, may be on children.
Kids who are infected can suffer delayed growth and cognitive impairment, as well as suffering
from nutritional ailments.
Experts estimate this worm kills upwards of sixty thousand people a year, but like other
parasitic worms, it can be killed off with antiparasitic medication.
But the biggest challenge of battling these worms is preventing infections and treating
people before they progress to serious cases.
One worm makes its presence known with a name that says “terror”.
#7.
Dracunculus Medinensis, or the Guinea Worm
Translated as “little dragon of the Mediterranean”, the proper name of the Guinea Worm gives away
that this worm is a killer.
The female worms are among the largest worms that can infect humans, growing to up to thirty-one
inches in length - longer than many snakes as they slither around in the human gut.
It’s not surprising that they can cause excruciating pain.
They infect people through contaminated drinking water and are most common in rural areas of
Africa and tropical regions like southwest Asia and India.
Once embedded in the human body, the effects can be deadly.
These worms cause a secondary disease as the female worm tries to emerge from the body
through the skin.
The chemicals she releases can cause infections, nausea, blisters, and itching.
But if she fails to emerge and gets stuck in the body, the worm can cause arthritis,
paralysis, or severe swelling from the infection and resulting immune response.
To treat this, doctors look for a blister where the worm is going to emerge and then
use warm water to lure the worm out.
They then slowly pull it out and wrap it around a stick.
It can take several days to remove a full-sized guinea worm, followed by treatment with antibiotics
and bandages.
These next parasites don’t wait for you to consume them.
#6.
Blood Fluke
Everyone is scared of leeches, those predatory worms that latch onto your skin in water and
start sucking your blood.
But the Blood Fluke takes that nasty MO to the next level.
After spending part of their life in a snail host, they lurk in water and enter the skin
of humans and proceed to feed on their blood.
They can live for decades, and can remain asymptomatic for years.
But when things go bad, they go VERY Bad.
When they cause a series of infections called schistosomiasis, they can affect almost every
part of the body.
Their most serious symptom is swelling, which can cause long-term damage to glands and can
even cause liver failure if left untreated.
While the parasite can be treated with the same antiparasitic medications useful against
other worms, these parasites are particularly common in Africa and are estimated to cause
up to two hundred thousand deaths a year - making the blood fluke one of the deadliest parasites
worldwide.
The next parasite is much more visible - and much more painful.
#5.
Jiggers.
Any dog or cat owner probably knows how annoying fleas are - constantly jumping everywhere
and biting.
But that’s nothing compared to the sand flea, also known as the jigger.
These fleas are common in Central and South America and have arrived in sub-Saharan Africa,
and they have an parasitic tactic that can make every step miserable.
The smallest known flea, they lurk in sand and attach to people as they burrow head-first
into the skin, usually on the foot.
This causes swelling and lesions as the female swells up with eggs.
This is just the beginning of the problem.
It’s common for victims of jiggers to have dozens or even hundreds of them embedded in
their feet.
As the fleas die off, this can cause infections that result in pain, scabbing, dead skin,
and permanent deformation of the toes.
As pulling the fleas out can cause their bodies to tear and leave parts behind, jigger infestations
are treated by a doctor to carefully remove any trace of the attached flea and disinfect
the area - which can be a lengthy process.
The next parasite also makes itself way too welcome in the human body.
#4.
The Human Bot Fly
Flies usually do little more than buzz around you, making that annoying sound.
But dermatobia hominis, or the human botfly, has a particularly invasive method of reproduction.
Its eggs are carried by other insects like mosquitoes which bite humans, transferring
the eggs into the open wound.
They hatch there, and the larva wedges itself in the human skin, growing there and creating
a visible grub sticking out of the skin.
Disgusting - but not dangerous...usually.
The biggest danger the human botfly poses is infection, because when you see a grub
sticking out of your skin, what’s the first thing you do?
You try to pull it out.
That’s a mistake, because while the body breaks off and the grub dies, the head and
jaws attaching it to the body stay in place.
That becomes a vector for potentially deadly infections.
The best way to safely remove a botfly larvae without medication or professional help?
To suffocate it with a coating of petroleum jelly.
After a day, it can be removed with tweezers.
It makes sense that Australia would have deadly parasites - and the next one adds a killer
kick to a common pest.
#3.
Australian Paralysis Tick
Ticks are common parasites, jumping from animal to human and sucking blood.
While they’re usually easy to remove with tweezers because they stay on the outside
of the body, their main threat is as a vector for deadly diseases - including the potentially
lethal Lyme Disease.
But one tick down under poses a bigger threat - one that can kill quickly.
Not only can it cause allergic reactions, but it secretes a toxin that can cause neuromuscular
function to fail.
Within eight to twelve hours of injection, paralysis can set in and even cause respiratory
failure if it is allowed to progress.
While these reactions aren’t common, with only about twenty fatalities reported in Australia,
this tick is one of Australia’s most feared animals.
And in the land of the bird-eating spiders, that’s saying something.
The penultimate parasite is invisible - and deadly.
#2.
Brain-Eating Amoeba
Not a true amoeba but a tiny shapeshifting organism, this microscopic bacteria-eater
lives in bodies of warm freshwater.
That means that it can be lurking anywhere people want to take a dip - rivers, lakes,
wells, or even swimming pools that aren’t treated with enough chlorine.
While it doesn’t function like other parasites and feed on humans long-term, this organism
has one major impact on humans - it causes a rare, but almost invariably fatal brain
infection that can kill a healthy person in days.
And it has shown up in the happiest place on Earth.
One of the earliest cases that brought this parasite to the public's attention was when
a young boy died of the infection after swimming at Disney’s River Country waterpark.
The parasite enters through the nasal cavity, usually when swimming but also occasionally
through rinsing out the sinuses.
It travels to the brain, where it changes up its usual diet of bacteria and starts eating
the brain’s astrocytes and neurons.
Symptoms appear after an average of five days - and by then, it’s already too late.
While this parasite can’t be spread between humans, it soon results in headache, nausea,
a stiff neck, decreasing brain function, seizures, and eventually death.
But no parasite causes as much death as our #1.
#1.
Malaria Plasmoidium
When you think about the deadly disease malaria, you probably think about mosquitos.
These biting pests do spread disease - but the actual cause of malaria is a single-celled
parasite called Plasmodium.
These protozoans enter the body through the mosquito’s saliva, and they infect red blood
cells.
The cells swell and burst, infecting the bloodstream - thus spreading to mosquitoes when they bite
a host containing the virus.
This makes it one of the fastest-spreading parasitic infections in the world, affecting
up to 600 million people a year.
And things can get bad for the unfortunate victims.
Malaria starts with simple symptoms including fever and chills, but some cases evolve into
something deadly.
Vomiting and severe sweating turn to anemia, seizures, and possible damage to the body’s
vital organs and bloodstream.
This can cause the victims to slip into a coma, suffer serious neurological issues,
and potentially die.
Several hundred thousand people die of malaria each year, most in the global south, and while
no vaccine is available, treatments are available to lessen the severity of symptoms.
The challenge is to outrace this fast-spreading parasite, which spreads as quickly as the
mosquito flies.
For more on a tiny organism that caused mass chaos, watch “Why Spanish Flu Killed Over
50 Million People - Deadliest Plague in Modern History”, or check out “13 Most Dangerous
Animals in History” for some larger predators.