Human Parasites! Three Of The Most Repulsive!

Brugia malayi - a roundworm parasite that causes lymphatic filariasis also known as elphantitis.
Brugia malayi - a roundworm parasite that causes lymphatic filariasis also known as elphantitis. | Source

The beasts that like to invade the human body!


For the most part parasites that infect humans are not of plague proportions. However, they can been found just about anywhere. None of these minuscule monsters are pleasant, but some more than others can cause stomach-churning repulsion. I've chosen three but these are merely the tip of an incredibly shocking ice-berg!

Basic Information

Human parasites are generally divided into two categories:

  • Endoparasites - found inside the body
  • Ectoparasites - found outside the body, for example on the skin

These groups will include numerous kinds of protozoa and worms. When infesting the human body they cause parasitic diseases. For the most part, having good, regular hygiene usually protects us from them.

Lastly, these parasites are not a modern phenomena. Archaeologists have found traces of both parasites and their eggs in human faeces dating to before 5000BCE. They have identified lung flukes, round worms, hook worms and tape worms among others.

Today most parasite infections can be treated successfully. However, there are some that can be fatal.

Larvae from the human botfly.
Larvae from the human botfly. | Source
A mosquito - one of many insects that infect humans with parasites.
A mosquito - one of many insects that infect humans with parasites. | Source
One of the major symptoms of lymphatic filariasis (elephantitis) showing the huge swellings in the legs due to disruption of the lympahtic system.
One of the major symptoms of lymphatic filariasis (elephantitis) showing the huge swellings in the legs due to disruption of the lympahtic system. | Source

Scary human parasites

Here are my top three most disgusting parasites that can invade the human body:

1. Dermatobia hominis - botfly

According to the US National Library of Medicine the botfly - normally found in South and Central America - mainly targets horses and cows to lay it's eggs. The species of botfly known to infest humans is dermatobia hominis, but thankfully, these infections are still rare. However, when it does happen, it's nasty.

Botflies - the word 'bot' means 'maggot'- all belong to the family 'Oestridae' and their life cycles can vary depending on the species. Other names for the botflies are:

  • warble flies
  • heel flies
  • gadflies

The botfly basically kidnaps another insect such as a house fly or mosquito and lays it's eggs on them. With the human botfly, the female usually uses either a mosquito or foliage. When the mosquito lands or people rub against foliage then the eggs can land on them. The eggs will then hatch and the larvae burrow into the skin. There is no pain at this stage all that can be seen is a small, red raised area. This is called in medical terms a myiasis. Normally with the botfly, a human will develop cutaneous myiasis, which means a larval infestation under the skin.

The larvae will stay in the host for about 5 to 10 weeks where it continues to grow and buries deeper into the skin. This causes the small bump to become larger and more like a boil with a hole in the middle that allows the parasite to breath. On occasion it's even possible to see the tail of the larva sticking out. Due to this burrowing, the area becomes painful, itchy and people often report that they can feel movement inside. These sensations are often experienced at night.

When development has finished, the larvae burrow back out of the skin and drop to the ground. When this happens they develop into adult flies. For most people the wounds do heal and normally there is little if any scarring. However, in rare cases some people develop a bacterial infection or other medical disease such as tetanus.

Treatment is usually by either cutting the larvae out or enticing them out by blocking up the hole that they breath through. When the larvae's air supply is cut off the come out onto the skin. The patient is also given a course of anti-biotics to help the wound to heal.


2. Dracunculus - guinea worm


Number two on the list is a horrible parasite known dracunculus or the guinea worm normally found in Africa and Asia. This parasite is caught by drinking stagnant water harbouring fleas. These tiny little insects can carry the guinea worm larvae. It's the larvae that infect people, eventually turning into worms. When people drink water that has a water flea in it, the flea is killed by the hydrochloric acid in the person's stomach. However, the guinea worm larvae are freed and burrow into the gut wall. The larvae then move through the body and make their way to the lower limbs.

According to the World Health Organisation (WHO), humans:

"are the only known reservoirs for this disease."

When the larvae first infect a person there is no indication that anything has happened. However, about a year after infestation a blister develops that is extremely painful and the sore usually appears on the lower leg. At this stage one or more worms start to emerge from the blistered area causing a burning sensation. One of the ways that the burning pain is relieved is when the area is immersed in water. When this happens the worm releases thousands of larvae into the water. The cycle begins again when the larvae infect the water fleas.

There is no actual preventative vaccine or cure for guinea worm. It can be removed via surgery by a doctor, but since the worms are found in some of the poorest countries and in remote areas, it's not an option open to many. Therefore, other means have to be used.

Traditionally the worm has to be removed only a few inches at a time by winding it around a stick. The worms can grow up to a meter long and so this process is not only painful, but can take weeks to get the worm out. The technique of removing the worm this way has to be slow and careful to prevent the worm from breaking and slipping back inside the body.

These parasites don't kill anyone. However, people infected become ill and unable to function normally for a considerable time. There are now a number of preventative measures being put in place in countries such as Mali, including providing safe water, education and treatment of natural water sources.


3. Filarial worm - causing Elephantitis (Lymphatic filariasis)

Lymphatic filariasi, (LF), is caused by microscopic worms that invade the lymphatic system of the body. The lymphatic system not only drains fluids from our tissues but has an infection-fighting role as well. There are three types of worm that may infect humans, all are carrried by the mosquito. The species are:

  • Wuchereria bancrofti - responsible for about 90% of cases
  • Brugia malayi - causes most of the remaining cases
  • B. Timori - can also cause LF.

Mosquitoes pick up the larvae of the worm from people who are already infected. When they bite another person, they inject the larvae into the their blood stream. The larvae then find their way to the lymphatic system.

This system - which helps to maintain the fluid balance between the blood and tissues - becomes severely disrupted. It's unclear whether this chaos is caused by the worms or by the reaction of the lymphatic system to them. What is certain is that once tissue damage has occurred the person becomes vulnerable to infection from bacteria or fungi. It is these secondary infections that cause many of the symptoms of LF. The adult worms live in the human body for up to eight years while millions of their larvae are dispersed in the blood.

Many people are infested as children but since the symptoms can take years to develop, they are often into adulthood before anything is noticed. One of the main symptoms is the grotesque swellings of the legs and torso, along with thickened, blistering skin that is darker in colour. This is where the other name for the disease - elephantitis - comes from, as the limbs can resemble those of an elephant.

In some areas of the world - the disease is now mainly found in tropical areas - people who are disfigured by the disease are sometimes shunned by their family and community and many never get the chance to marry. It is obviously a very disabling condition and numerous sufferers are unable to work. The saddest point about the disease is that it is treatable, however, the medications necessary are not always available to the people who need it.

The guinea worm being withdrawn from a human leg by using a matchstick.
The guinea worm being withdrawn from a human leg by using a matchstick. | Source

Which of the three parasites do you find the most repulsive?

  • The botfly
  • The guinea worm
  • The filarial worm - causing elephantitis
See results without voting

Parasites are here to stay

Although the parasites described here are largely found in African/Asian areas or other tropical regions, there can be threats to Western people travelling for work or going on holiday. In addition, due to the ever increasing traffic of goods and people around the world, it's much easier for parasites and other infection dangers to hitchhike to different countries. Add to this the global changes in weather and the environment, who knows what repulsive little critters we might find outside our own doorstep in the not too distant future?

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Comments 21 comments

Sneha Sunny profile image

Sneha Sunny 3 years ago from India

Scary little creatures! It is so easy to get infested by these worms. They are present almost everywhere. Although as you mentioned we can prevent their infestation simply by maintaining hygiene still the incidences of people getting infestation is very high. I find filariasis most dangerous 'cause the swelling never goes even after the worm is killed by the use of medicine!

This was a great, useful read. Thanks for sharing this useful information.


mary615 profile image

mary615 3 years ago from Florida

Well, I have to tell you: this was a very informative Hub, but not one I'd like to read before my morning coffee. You did a good job with your research, though.

There is a parasite that enters the human when they swim in infected water here in Florida. I cannot remember the name of it right now. They are found in dirty streams that kids sometimes play in.

I couldn't vote cause there is no "all of them".

I voted UP, etc.


Bumpsysmum profile image

Bumpsysmum 3 years ago from Cambridgeshire

Wow! I had heard about some of these. The Guinea worm sounds vile, imagine having to wait weeks to get it out, yuk! Very interesting and brings to our attention how lucky we are not to be exposed to these parasites. Great hub, interesting, awesome and up.


vocalcoach profile image

vocalcoach 3 years ago from Nashville Tn.

Ugh - this is an awful condition to have. The photo tells it all. Too bad these parasites can't be done away with. Useful hub but at the same time, something I don't want to think about. :) Voted up and useful.


sparkster profile image

sparkster 3 years ago from United Kingdom

Great article, great information and you can't help being interested by it but ewww... so disgusting too!


Rosemay50 profile image

Rosemay50 3 years ago from Hawkes Bay - NewZealand

Ugh I was just thinking about lunch too,

These horrible things are gross. The fact that they can live in our bodies for years before we know they are there is frightning.

But its good to know to be extra careful, especially for travellers.

I know when we visited Egypt we couldn't eat fruit or salad that would have been washed in water.

Another awesome but yukky hub my friend


Gypsy Rose Lee profile image

Gypsy Rose Lee 3 years ago from Riga, Latvia

Voted up and interesting. I will say this was a fascinating and informative hub. Things people should know about and be aware of - parasites. On the other hand I could say this is more terrifying than a horror movie because it's reality. Passing this on.


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Sneha Sunny - I love your name!!!

Many thanks for stopping by and for leaving a great comment! That's interesting abought the swelling still being there after getting medication, I didn't realise that!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi mary615, many thanks for stopping by and for very interesting comment. I was particularly interested in the parasite that you have in Florida in the dirty streams - whatever it is I bet it's a horror!! Thanks too for the vote up, really appreciated!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Bumpsysmum, many thanks for stopping by and for leaving a comment - really appreciated!!

Yes they are yuky!! And the thought of having to wait so long to get a worm out of your body is absolutely gross - I would be sick every day thinking about it I think!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi vocalcoach many thanks for stopping by.

Yes, these are really terrible conditions to have and I for one would be glad to see the back of them!!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi sparkster, thanks for stopping by and for taking the time to leave a comment!

LOL!! Yes they are fascinating and maybe part of that is because they are so gross!!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

LOL!!! Sorry Rosemay, hope you finally managed to eat something - but aren't these things gross!! I did the research and writing after I had eaten, I really couldn't have put any food in my mouth while reading about these things!!

I've heard Egypt does have a lot of quite nasty critters going around and I would probably wash everything as well to be on the safe side!!


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Rasma, lovely as always to hear from you and glad that you enjoyed the hub.

I think folks should know about these things, especially today as so many people are going on adventure holidays into very rural areas, perhaps without knowing just what could be lurking there!! And I agree, these critters are very scary and revolting!


Rosemay50 profile image

Rosemay50 3 years ago from Hawkes Bay - NewZealand

Haha oh dear Helen you missed my point, we couldn't eat anything because it HAD been washed. The water is so contaminated. It was necessary to drink only bottled water that was imported.


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi Rosemay!!! LOL!!!! I've just re-read your comment - sorry!!!! I've just celebrated my 51st birthday and it seems like I've lost another huge wad of brain cells!! LOL!!


Rosemay50 profile image

Rosemay50 3 years ago from Hawkes Bay - NewZealand

Well a belated Happy Birthday, I hope you had a wonderful day. I was 63 on Valentine's Day so probably a few less brain cells than you LOL.


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Ohhh Happy Birthday Rosemay - hope you had a lovely day!! Now going with the beautiful poetry I've just read, I think you have still have a few trillion cells left to play with!!


gail641 profile image

gail641 3 years ago from Mason City

Very interesting hub! The three critters are really scary!!! The guinea worm is so gross, along with the other two parasites-they are all yucky!!! With globle warming they could become even worse than they already are, and with people doing a lot more moving around on the globe. I hope to never see the three parasites ever.


Seeker7 profile image

Seeker7 3 years ago from Fife, Scotland Author

Hi gail641. many thanks for stopping by and glad you found the hub interesting. I agree the guinea worm has to be the worst and it affects so many people only because they don't have proper drinking water. I hope I never encounter them either!!


gail641 profile image

gail641 3 years ago from Mason City

Hi Seeker7, you're welcome. I would never want to encounter them either!!

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