Believe it or not, there are countless organisms living in your body right now. (If you don't want to believe it, you may be delusional...or a pork tapeworm may be living in your brain.) Sure, some are helpful bacteria that keep your body regulated. Others, however, are less than friendly.
In fact, they will make you want to jump out of your own skin.
1. An Ascaris infection is your worst nightmare.
Ascariasis is a (terrifying) disease caused by the parasitic roundworm Ascaris lumbricoides. A person can become infected if they eat or drink anything containing Ascaris eggs. Those eggs are usually found in feces. (Gross.)
Once infected, the worms can actually grow within your body. This nightmare fuel can also grow large enough to block your intestine.
When large numbers of worms get tangled into a bolus (or parasite rat king, if you will), they may need to be removed with surgery.
2. Wuchereria Bancrofti is gross on its own, but it can cause something worse.
This awesome parasitic roundworm lives in humans and is the major cause of lymphatic filariasis (also known as elephantiasis).
There are some cases of lymphatic filariasis that present with no symptoms...
In other cases, however, people experienced extreme swelling in the arms, legs, or genitals. It's also possible for the skin to become thicker and more painful to the touch. No only is the disease painful, but it causes countless problems socially because of the altered appearance.
3. The familiar (but awful) tapeworm is everywhere.
When you get a tapeworm infection, it's usually because you ingested live tapeworm larvae via eating undercooked food.
Once inside your body, a larva can grow into a very large adult tapeworm (see below).
(Yes. It is terrifying!) But the parasites don't have to be full grown to cause trouble. Tapeworm larvae can cause diseases, as well, like cysticercosis.
4. This special tapeworm wants you to eat more pork.
You can get this kind of tapeworm by eating undercooked pork products. (There's a reason why meat thermometers exist.) If you become infected, you may be asymptomatic.
...but you also could get a brain infection. Whoops!
Accidental infection in humans by the larval stage of the tapeworm can cause cysticercosis (which is a tissue infection). You can get it nearly anywhere -- including your brain. Neurocysticercosis is a major cause of epilepsy. You do not want neurocysticercosis.
5. Strongyloides will make your skin crawl. Literally.
These nasty little threadworms can live in the soil...and if they burrow into your skin, they can eventually infect your bloodstream and small intestine.
Not only that, but they can give you terrible lesions or rashes.
When the parasite enters your body through your skin, it can leave behind rashes as the larvae migrate. They crawl through your skin layers 'til they get where they need to be.
6. Have a pet? They can give you diphyllobothroid tapeworms that infect your brain, causing sparganosis.
Dogs and cats can have adult tapeworms living in their intestines. When a human becomes infected through contact with feces, the larvae can migrate to their skin layers, where they typically develop into a painful nodule. Fun!
But that's not all! The infection can also move to your brain and eyes.
Thankfully, the parasites can be treated through surgery or by taking Praziquantel. (But only after ruining your year.)
7. Acanthamoeba keratitis (a.k.a. "River Blindness") will make you avoid wearing contacts ever again.
Basically, the amoebas can squirm their way into your eye's cornea. There, they can do damage that results in visual impairment or blindness.
Bad news: If you wear contact lenses, that's where Acanthamoeba love to live.
If you go swimming or surfing, you need to remove your contacts. Otherwise, the amoebas could get in between the lens and your eye and stay there for a while. (Oh, and you can also get them from not disinfecting your contacts.)
8. The rat lungworm will make you hate eating vegetables. And possibly snails.
This parasitic nematode is often found in the pulmonary arteries of rats, but humans can become infected by consuming snails, vegetables, or even water tainted by infected rats. The larvae can be transported via blood to your central nervous system. There, they can cause the very dangerous eosinophilic meningitis. That disease can lead to permanent brain damage...or death.
9. Pinworms will kick your butt. (Just kidding, they'll just lay eggs inside of your butt.)
Pinworms are nasty little parasites that can either be ingested...or will insert themselves into your anus. From your butt, the larvae or eggs can be transferred to almost anything. So, technically, you can have pinworms down in your nether regions, but you can transfer them to your food via your hands...and then you can ingest them all over again. Thanks, pinworms!
10. The super-scary amoeba Naegleria fowleri wants to eat your brain.
These nasty zombie amoebas are the reason why many parents are afraid to let their kids swim in ponds, lakes, or rivers. The pathogenic protists live in the water, but they can enter your body through your nose...and kill you.
Naegleriasis (or primary amoebic meningoencephalitis) is a lethal infection and has recently taken the lives of children.
When the N. fowleri is in your body, it invades your brain through nasal tissue and olfactory nerve tissue. (Now, using a neti pot suddenly sounds terrifying.)
11. The African eye worm will (you guessed it) live in your eye!
Oh, the horrors of nature. Loiasis is caused by the parasitic worm Loa loa. Even though the name sounds cute, this is not cute. Not at all.
You get loiasis by being bitten by an infected deerfly.
Once infected, you may get itchy bumps that come and go (often near joints). ...but you may also develop a worm that crawls across the surface of your eye.
12. The Paragonimus westermani wants to get in your lungs and cause a ruckus (paragonimiasis).
You can ingest one of those lovely lung flukes in Asia and in South America. Typically, humans are infected by eating inadequately prepared crab or crayfish.
They live in your intestines...until they plow through the abdominal wall and diaphragm. Then, they move into your lungs.
From there, they grow into big, strong worms that can move into your brain and striated muscles.
13. Mites: they're everywhere and they are not afraid to make your life a living hell.
The worst thing about trombiculid mites, also known as "chiggers," is that they are everywhere.
They're in grass, dust, rocks, sidewalks, wood, shoes, socks...and basically anywhere else you can think of. You can treat your yard for chiggers, but they're so tiny, you may never get them all.
Chiggers like to bite humans, and when they do, they can cause trombiculidiasis (a rash). It's ugly, it's uncomfortable, and it was caused by basically-invisible mites. Don't you feel great?
14. Tiny flies can cause cutaneous leishmaniasis. Leishmaniasis will give you bleeding ulcers everywhere.
The bites of sandflies can cause a disease called leishmaniasis. This disease causes ulcers to appear on your skin, mouth, and nose. The visceral form of the disease starts with skin ulcers and then later presents with fever and an enlarged spleen and liver.
If you are traveling in Africa or parts of Asia, it may be a good idea to sleep under nets treated with insecticide.
Otherwise, you could be bitten by sandflies as you sleep...and end up with your flesh rotting off in the near future.
15. This itty bitty candiru fish is cute...and likes to swim up your urethra (allegedly).
There are horror stories online about these pencil catfish lodging themselves into people's urethras...but most of them are anecdotal. In fact, scientists consider them urban legends.
It is true, however, that this fish is also known as the "vampire catfish." That's because they like to suck your blood.
In a short burst, these parasitic fish propel their way into an opening. Once they wiggle into that opening, their head spines hold them in place, allowing them to feast upon the blood of the organism. (Now that "swimming into your pee hole" doesn't sound so crazy, does it?)
16. The great and terrible bot fly larvae are here to haunt your dreams.
Bot fly larvae are internal parasites of many mammals. They will grow in either a host's flesh or in their gut. They are a truly terrible parasite that should haunt you forever.
What makes a botfly so awful is how the larvae live in your skin. At first, the host may think they just have a swollen lymph node or mosquito bite.
Then, the bump keeps growing...until the larva burrows out of the skin. Botflies can be removed, but it's not a pretty sight.
This Earth can be incredibly majestic and fill you with awe...but never forget that it can also give you worms that live in your eyes and brain. Good luck sleeping tonight!