Posted in Monday Mayhem

Top 10 Most Horrifying Parasites

Welcome to Monday Mayhem where today, I will be talking about parasites. I was browsing YouTube the other day and came upon a video that’d caused me to delve deeper into the creepy world of parasites. The video goes by the name 10 Horrifying Parasites That Might Be Living Inside You. As I watched, a thought passed through my mind and it went something like this: With all these terrifying parasites on the loose, it’s a wonder why we don’t have zombies running around wreaking havoc on the planet.

Leishmania [Photo credit: CDC Public Health Image Library]
Leishmania [Photo credit: CDC Public Health Image Library]
If you haven’t seen the video, here’s a breakdown of its contents. You may want to hold your stomach, as these may get gruesome in description.

10. Leishmania—Transmitted by sandfly bites, this parasite can cause hideous and painful sores. Up to two hundred lesions can form on the body leading to disability and scars. [Source: WHO]

9. Loa Loa—Lives inside the host for up to seventeen years, moving under the skin and causing swelling. Adult worms visibly move across the surface of the eyes. The treatment can result in personality changes. [Source: CDC, Popular Science]

8. Ascaris Lumbricoides—Over one billion people might be hosting these worms that grow up to thirty five centimeters in length. They can live for two years in the intestine and can block it. Victims often show no symptoms. [Source: CDC]

7. Onchocerca Volvulus—A worm that lives inside humans for fifteen years and grows half a meter (over one and a half feet) long. Disfigures skin and causes “River Blindness” resulting in sight loss. Up to eighteen million people are afflicted. [Source: WHO, CNN]

6. Toxoplasma Gondii—Up to fifty percent of human brains are infected with this this parasite spread by cats. Increases risk taking and depression. It might also explain national cultural differences. [Source: NY Times, Huffington Post, Scientific American]

5. Trypanosoma Brucei—Victims have trouble sleeping, poor coordination and are confused. Often fatal, symptoms of “Sleeping Sickness” can take years to appear when it’s already too late. [Source: WHO]

Entamoeba Histolytica [Photo credit: CDC Public Health Image Library]
Entamoeba Histolytica [Photo credit: CDC Public Health Image Library]
4. Entamoeba Histolytica—One of the biggest parasitic killers on earth, claiming seventy thousand lives annually. Causes disease amoebiasis that can lead to chronic diarrhea and liver abscesses. [Source: New Scientist, CDIPD]

3. Trichuris Trichiura—Resides in the large intestine and is said to infect eight hundred million worldwide. Leads to diarrhea and anemia but in extreme cases the rectum can protrude from the anus. [Source: Scientific American]

2. Wuchereria Bancrofti—Over one billion people are at risk from this parasite that causes Elephantiasis. Victims suffer from enlarged body parts and resulting disability. [Source: WHO]

1. Naegleria Fowleri—Found in freshwater, the “Brain-Eating Amoeba” targets the brain and nervous system. Can cause PAM, a form of meningitis with a ninety-eight percent mortality rate that kills in weeks. [Source: National Geographic, Stanford University, CDC]

Now that you’ve read the Top 10 Most Horrifying Parasites list, it certainly provides another opportunity to look at other Top 10 lists. How about: Top 10 Ways to Kill Parasites? Or this one: Top 10 Cures for Parasites. If those lists exist, I’m sure I’ll be the first one to see what they have to say. For the time being, these Top 10 parasites have left me to wish I hadn’t known about them. Perhaps they have done the same for you.


What other parasites are there that I haven’t mentioned?


Jack Flacco is an author and the founder of Looking to God Ministries, an organization dedicated to spreading the Word of God through outreach programs, literature and preaching.

55 thoughts on “Top 10 Most Horrifying Parasites

  1. Okay scary list. Also mostly impossible to see and combat. Unlike zombies which you can see, here and aim at. Yep, I’ll take my apocalypses with zombies please.

  2. I’m tempted to look up ” Blood Music “, a novel by Greg Bear. It’s about a genetically – engineered parasite that escapes the lab, then infects 2 people, mutating them, then it spreads across the Northern Hemisphere, then the globe. It was quite an interesting read, even though I have no idea what happened to my copy of it. Shades of ” Andromeda Strain ” !

  3. yeesh – it’s amazing how one of the scariest things are usually things we can’t see. interesting post – i would like it but it’s too terrifying to like!

    1. I find oddly interesting, but my tastes have always leaned to the odd & obscure ( strange, outre, etc. ).

      1. Considering the nature of the subject matter, this has been a remarkable & lively discussion thread !! More popular than the zombie discussion threads, maybe ? Hmm ?

    1. I believe THAT was the guy. It’s been quite a while since I read it. But the gist of it is that machines have become the dominant ” species ” on Earth, & they discover that there’s at least one human alive.

      1. It was a good read, as I remember. I have an appreciation of post – apocalyptic / post human ( society ) media.

  4. I have to tell you. This is so disgusting that I can’t/won’t even read it. But I had to comment about how gross this post is, and how wicked your sense of humor is. Interesting — if creepy — post! 🙂

    1. I have one cousin in the area where I live who is positively revolted & REPULSED by subjects such as this, so naturally I thought about sending it to her, just to be a smart – aleck.
      Whereas I have had an interest in subjects like this for a long, even taking a forensic anatomy / pathology class in college. 🙂

      1. I’m not quite that bad, but I could imagine a few people who would be delighted to receive such a post in a message. haha

      2. I also had to desensitize fairly quickly, because I once worked in a hospital, & part of our orientation was to go through a lab where tissue samples were processed. No weak stomachs allowed !

      3. & attending a class taught by Dr. Wm. Bass ( Of ” The Body Farm ” fame ) & being a fan of shows like ” BONES ” & ” NCIS ” ( Big fan of Dr. ” Ducky ” Mallard ).

  5. The brotherinlawaditius. It comes and stays, drinks and eats the host out of house and home and can only be eradicated with an insistence on cleaning one’s room.

  6. I find that this is, really, quite an interesting subject. I’m going to suggest something potentially very, very STUPID, so please bear with me. There are NO PARASITES who have beneficial relationships with their hosts, yes ? I’m thinking of the E. Coli virus. It can be deadly, & yet, in fact, we NEED it to maintain our digestive system to make sure it functions within ” acceptable parameters “.

    1. While technically parasites live in or on hosts, when they benefit each other it is called symbiosis. Examples are as you say E. coli, others include photosynthetic elements of some plant cells.

      1. I thought so – Even though E. Coli is a virus & technically digestion would be virtually impossible without it residing in our guts.

      2. we depend on them for digestion because that’s how our guts have developed over many thousands of years – it’s quite amazing the symbiosis that exists all around us, even including some forms of social interaction – take a successful marriage, some see marriage as free prostitution on the part of the man or living off the man in the case of a married woman. I think people that see marriage like that are bitter and very short-sighted. Look at the people in successful marriages – even if they argue a lot, they have a certain glow to their relationship that is 100% beautifully co-dependent, and a much nicer way of describing symbiosis!

      3. A very scholarly way to explain relationships both human & animal ( symbiotes & parasites ** are ** animals, I guess ).
        I often wonder if extra – terrestrial life will be of a symbiotic / parasitic variety, a physically smaller entity using a larger, sturdier host. I obviously watch a LOT of Sci – Fi.

      4. I think you have made a correct link between various hosts. There is an argument that says a lot of our microbial life on Earth was originally extra-terrestrial, so why not these phytoblasts in cells that supply energy to the animal cells by performing photosynthesis. Lichen are another example of this, they are multiple cell types living together, some produce energy, others produce protection against weather, etc. and reproduce. Science fiction is a great way to expound on this stuff and take it that next step into unreality. Or do they? perhaps it’s always there & we just don’t know it! BTW – I am a biologist by training, one of my life loves 🙂

      5. I have been gaining some interesting insights in this discussion of what some would consider an ” unwholesome “, ” disgusting “, etc., topic. It’s simply what makes the mechanism of our little world tick – Even if it wouldn’t make for polite dinner conversation or something one would bring up at a party ! I became interested in subjects like this approximately half a lifetime ago.

        & there are people who think that humans are somewhat parasitic in nature, in view of environmental damage that is directly or indirectly our responsibility. But that’s possibly another subject for another time & venue.

      6. Interesting perspective 🙂 In The Matrix, the computer entity viewed humans as a virus! That’s the beauty of humans, we can be all things to all creatures!!

      7. Maybe hundreds of years from now, computers, advanced AI’s & sentient machines will view us not so much as ” parasites ” but in a way similar to the way that we view apes & proto – simians. That would be a LITTLE more flattering, IMHO. Read the short story ( But ) Who Can Replace a Man ? “, by – I think Clifford Simak.

  7. I clicked the like button, but how can we ‘like’ brain-eating worms and three foot long intestine blocker-uppers! Imagine if these things developed some kind of intelligence and self-awareness, we’d be done for as a species. The cat parasite is particularly bothersome seeing as these things are all around us. That’s why I prefer dogs.

    1. I would say that most parasites act on instinct alone, like a flower growing towards the light or a vine or fungus seeking moisture & sustenance. Ramping up their intelligence & sentience would be an almost God – like ( Devil – like / diabolical ? ) feat & would require re – jiggering, re – wiring & re working their comparatively primitive nervous systems.
      If they did develop a form of sentience, or at least could be controlled somehow, they would make formidable ( AKA scary as hell ) bio – weapons.

  8. These would make great bio – weapons. That’s also a somewhat disquieting thought, actually……

  9. I’ve heard that either HR Giger or someone else got the idea for the embryonic aliens ( either the ones just hatching from their egg – cases or the ” face – huggers ” in ” ALIEN ” from studying images of parasites.
    We might think of some of them as alien, but they might very well see US as alien, or at least as large mobile biospheres that they can set up shop, hearth & home ( with plenty of places to dine 🙂 ).
    I took 1 course in forensic anatomy who’s a well – known expert in ALL things forensic, back in the dim mists of the 80’s. Only ONE course, but the interest stuck with me.

  10. Nice one Jack.
    Here’s number 11 for you – this one always scared the s**t out of me! – more common than you think and seriously frightening. When they remove the cyst from the brain (or other organ but the brain is particularly scary), they have to be careful not to spill the contents as it contains loads of the creatures – even one left behind will create the problem again.
    Don’t you just love parasites?!

      1. Nothing new on earth – it’s all a rehash! Looking up close and personal at these critters always looks like a monster – always great fodder for writers 🙂

    1. Having a Hydatid cyst in or near the brain seems like having a grenade with the pin pulled in ones’ body. Must look at your wiki link.

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