The 13th Floor

This Horrifying Parasite Could Be Living Inside You Right Now

The world wriggles with strange things, and nature is a real horror show. As we grow, we acquire all sorts of biological hitchhikers — some looking for temporary lodgings, others hoping for a permanent stay. Open a science textbook, and you can touch the pulse of primal fear; predators and prey, hosts and parasites! With all the horror at hand, we have only to look within to find some natural thrills. Read on to activate your inner paranoiac.

Imagine a worm capable of creating a cyst that can attach to any organ inside your body. It prefers attaching to your liver or lungs, but will make do with your brain, if it must. It can hide inside your body for years without making anyone suspect its presence. Oh, and once that cyst is growing, some larval friends will start to live there, too. So really, once Echinococcus granulosus visits, you’re never alone again!

Image Credit:
Image Credit:

That’s right, this worm really exists. The Echinococcus granulosus does not want to live inside a human body, but like any plucky pioneer, it makes do with the environment at hand. Once its eggs hatch in your small intestine and release oncospheres (a larval form of this worm), the oncospheres will burrow right through the intestinal wall until they reach your bloodstream. The ol’ scarlet log flume may take the oncospheres on many wonderful adventures, but really every larva there is just looking for a little patch of flesh to call home.

Our organs aren’t prime carnivorous territory (we’re shitty omnivorous turf – the abandoned lots of  Echinococcus granulosus real estate), but the larvae may drift and set up shop making a hydatid cyst on your liver or lungs. Maybe your kidneys, or your brain, or your eyes. A hydatid cyst can exist within the human body completely undetected for years — possibly decades — because its growth rate is insidiously slow, and generally doesn’t cause noticeable symptoms. Usually people only become aware of the cyst once it’s so big, that it’s causing complications to nearby organs and whatnot.

Neat fact about these cysts: they can grow cysts inside themselves! Also, each cyst is filled with a fluid that, when released into the human body, can throw you into anaphylactic shock. And yes, anaphylactic shock can kill you. So each cyst is essentially a tiny water balloon filled with poison. Oh, and there’s also the issue of each cyst filling with multiple larvae. If you break a cyst, you risk killing yourself and reinfection — because if the anaphylactic shock didn’t kill you, perhaps news of reinfection will seal the deal at that point.

Because these cysts are so good at being unobserved, we can only estimate as to its infection numbers, but up to one million people may be carrying them at any given time. And maybe, just maybe, you are one of those gracious hosts.

Image Credit: InterCom


You can get this parasite pal from playing with dogs.

This worm really wants to be inside ungulates (think sheep or goats), or carnivores (dogs) in order to continue its lifecycle to healthy adulthood. Humans are duds for this parasite, sex-wise; the human race is the ultimate Echinococcus granulosus cockblock. That’s why when the eggs of this parasite are passed out through dog excrement and then ingested by humans – AND I’M LOOKING AT YOU PEOPLE WHO LET DOGS LICK THEIR FACES INDISCRIMINATELY — it’s actually a real bummer for Echinococcus granulosus.


O.K., so there is hope, here.

To decrease your chance of getting this, never feed your dogs offal, especially guts of the sheep and goat variety. There are vaccines that dogs (and sheep) can get to prevent infection in the first place, which is lovely and wonderful – because hey, once a dog is vaccinated, it’s just can’t transmit the parasite.

If you think you might have a hydatid cyst, get thee hence to a doctor! The cysts can be removed surgically, or be treated with something called a PAIR procedure, which means that after the docs are done, your body gets to keep the physical cyst as a (larva-free) souvenir! Won’t THAT give your grandchildren something to be terrified of later on (Gramps lifts shirt, exposes tummy, “Poke that! Go on! Did I ever tell you how I got that? Why are you crying, dammit? Where’s your mother?”)? There are even drugs you can take after they remove your cyst to help reduce your reinfection rate! O blessed science!

People with the highest risk factors to contract Echinococcus granulosus do things like: slaughter animals at home, feed offal to their dogs, live closely with their dogs, and play with their dogs. So yes, you may be in an at-risk group, but you’re probably not feeding your dogs cyst-infected guts… are you?