Archive for the ‘Nematodes’ Category

Worms can always get worse

Posted: May 30, 2014 in Nematodes

Well, it has been a while since I updated here, and so I thought we’ll return with a suitably horrific Horrific Animal of the World, in our long running campaign to convince the world that hope is a lie, despair is rational and that Mother Nature is a vile, heartless, cruel and sadistic monster, with whom a flamethrower is the only possible mode of communication.

 

Once again, rapacious corporate greed and short term thinking save us all!

 

There are a number of horrible diseases you can contract through seemingly normal activities. Unprotected sex can get you AIDS. Badly prepared food can get you a nasty case of botulism , caused by the Clostridium botulinum bacteria which produces what is widely regarded as the most toxic poison on the planet. And getting bitten by an insect can get you any one of literally dozens of diseases, from Lyme disease to malaria to yellow fever to dengue fever to good old fashioned plague to West Nile Virus, all of which can comprehensively ruin your day.

 
Yup. Just one bite from the right (or to be more accurate, wrong) insect can severely impact your quality of life, up to and including killing you. Most of these diseases you’ve probably heard of, but you’ve probably never heard of Lymphatic filariasi, in a case of ‘ignorance is bliss’. This isn’t because it is harmless, or just causes a coughing fit, or whatever. The best thing one can say about this disease is that it doesn’t directly kill you. However it does impair your body’s immune system, cause agonising pain and disfigure you in some of the most horrific ways imaginable, which it does to about forty million people worldwide.

 

This is a good time to mention that this entry will contain some disturbing images. Actually, we probably should’ve mentioned this earlier. Sorry about that. (Image credit: Blaxter Lab. University of Edinburgh.)

 

This disease is caused by small parasitic nematode worms, and transmitted by mosquitoes, as is the case with a distressingly high number of unpleasant diseases. Most cases of this disease are caused by one specific type of nematode – Wuchereria bancrofti – although all in all three species in total can cause this effect (the other two being Brugia malayi and B. timori). In any case, the way these worms cause havoc is the same across all four species.

 

It doesn’t look like much – a small, whitish, translucent worm like thing between 1.4 and 2.5 inches long (depending on whether its a boy hellworm or a girl hellworm – and if that sounds small remember there can be thousands of these things living inside you), with no eyes, no visible mouth and no redeeming features whatsoever. Usually, the males and females are found coiled together, which would be sweet if they weren’t abominations against all that is pure and good, and the females can produce thousands of offspring, which is one of the many, many features you don’t want in a ‘disease causing parasitic worm’.
These animals spread themselves via mosquitoes. So, a mosquito comes in, slurps some blood up from an infected person, and flies off again. Inside that blood it drank are some juvenile worms, called microfilaria. When the mosquito bites another human, the microfilaria emerge into the bloodstream, and then migrate into the lymphatic system, which is an important part of the body’s immune system.
Mostly, they migrate to lymph nodes in the lower half of the body, where they mature from hellish juveniles to obscene adults. This part will be important later. The worms then mate and produce many thousands of offspring, which then enter the bloodstream. Normally, the microfilaria live in the ‘deeper’ regions of the circulatory system, but at night they detect chemical changes in the bloodstream and they migrate into the upper circulatory system, in order that when a mosquito bites they can be sucked up along with the blood.
So how can they cause this?

 

 

“This” being both a horrific disease and the loss of any belief in a loving Deity.

Many infections of this nematode have few (visible) symptoms – although as the World Health Organisation (http://www.who.int/mediacentre/factsheets/fs102/en/) notes, often children who show no symptoms suffer from damage to their lymphatic system as well as renal problems (Ottesen et al 1997). Sometimes, sufferers suffer from short term fever, chills, skin infections and painful lymph nodes, symptoms which usually go away after a week or so. This is even less pleasant than it sounds, as frequently (male) victims also suffer severe pain due to inflamation in the genital region. However, the disease can progress to cause chronic elephantiasis.

 

This. (Imagecredit http://1.bp.blogspot.com)

Originally, it was thought that the acute infections were caused by the junivile worms, via causing an infection response by the immune system, and the chronic elephantiasis was caused simply by the masses of (adult) worms blocking the lymphatic channels, meaning fluid accumalated in the lower regions of the body. However, it is now thought that this is a bit too simplistic. Broadly, it is thought that it is the adult worms in the lymphatic fluid, rather than the junivile worms in the bloodstream, which cause most of the damage. And rather than the worms simply blocking the lymphatic system, it now appears that there’s a complex interaction between living worms, dead worms, the immune response to the worms, and bacterial infections, which cause elephantiasis (Dreyer et al, 2000). In any event, in the worst case scenario, a single bite by a mosquito can lead to huge, disfiguring swellings of the legs and, perhaps even worse,  the genitals.

We could show you a picture of the latter, but I’m not willing to search for it and I doubt you wish to look at it. So here are some cute panda babies instead. (Imagecredit: Fineartamerica.com)

There is one spot of hope, though.  Since W. bancrofti needs humans to reproduce inside (it has no other hosts) eradication programs are a real possibility. As this blog stated with the guinea worm, sometimes total extinction of a unique species is a highly, highly desirable outcome.
And on that note, see you all next time.

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Generally, biologists tend to get pretty annoyed when a species goes extinct. It doesn’t matter if its a Panda, an Emperor Penguin, or some ant living under leaves in Uzbekistan which no one has ever heard of before. Whatever the animal, there is bound to be, somewhere, someone who cares about it.

Which means that the Guinea Worm, or to give it its full name Dracunculus medinensis, is so utterly horrific that really, no one seems that bothered about the fact that soon it will have gone extinct, except for people on a website called SavetheGuineaWorm.com, which is either a) a spoof or b), like everything on the Internet, run solely by mad people. And there’s a reason why it has attracted so little sympathy. Even its name indicates that it unpleasant. The first thing you probably thought of when you saw it is that it looks like ‘Dracula’, and so is a parasite, which is half right. It is actually apparantly derived from the Latin phrase ‘affliction with little Dragons’ (Barry 2007) which means that it is a parasite that causes agonising pain. (For those of you wondering why ‘Dracula’ and ‘Draco’ (Latin for ‘dragon’) sound the same (you seriously need to get a life if you are) , its because the original Dracula was a member of the Order of the Dragon, possibly the best name of anything, ever,  formed to protect Eastern Europe from the Turks).

Order of the Dragon

For an Order with such a cool name, this does look like it was designed by a nine year old who just thought of a cool name for his gang. But frankly, we’d rather go with any picture, no matter how poorly drawn, than actually show you a guinea worm. (Credit Wikimedia Commons)

So anyway, ignoring the anecdotes about a tyrant so horrific he inspired the most influential monster ever, and getting back to something truly horrible, we have the Guinea worm, which has been around so long it was thought to have inspired the  asklepian, the international ‘symbol’ of healing. (It nowadays features a snake, but could date from a time when the best time to extract the worm was to twist it out using a stick). 

This worm, in its larval form, lives in dirty water, swimming around, presumably thinking purely Evil thoughts. These larvae infect copepods, tiny water fleas, which are otherwise pretty much harmless. Sooner or later, a hapless human will drink this water, and swallow a number of these infected water fleas. And this is where things move away from ‘mildly sick making’ to a string of stuttering obscenities.

Inside the stomach is pretty strong hydrochloric acid, which dissolves away the flea but leaves the young worm (wormling ?) unharmed. So basically, this worm is so tough it can survive being immersed in acid, which dissolves its original host away to nothing, which we have to admit is kind of badass as well as utterly terrifying. The worm then finds a nice warm body cavity, mates, and if its a female lays its eggs, whilst it continues to grow, sometimes reaching lengths of up to sixty centimeters  (If you are wondering what happened to the males, they die and get absorbed by the female; meaning misogyny is a common but short lived attitude along Guinea Worm males).

So, nothing much happens for about a year (Barry 2007), until the female(s) inside the host (yes, if you are really, really, really unlucky you can have as many as forty of them inside you) get restive; as this point they may be over two feet long and be as thick as a ‘spaghetti strand’ according to one account, presumably written by a rather hungry student. They want their young to experience the big, wide world, and the way to do that is to get back into the water. And the way to do that is to make humans go into the water. And, because nature hates us, it designed a method that is both effective and terrifically cruel. Like most of nature, really.

They  stimulate a ‘burning’ sensation in the affected parts of the body. Because, you see, these worms have somehow evolved the ability to make humans feel pain; because that makes humans want to dunk the affected body part in water. Basically, the worm is using an admittedly very crude form of mind control, ‘knowing’ that burning pain makes people want to go into water to cool it down. An almost brainless invertebrate is manipulating the planet’s apex species into doing exactly what it wants via torturing it, which is probably enough to utterly refute he existence of a loving God on its own. The pain is said to be agonizing  and can effectively cripple people for months on end.  The eggs are released into the water, and the whole horrible cycle starts again. Oh, and if you thought you could just pull the worm out, you can’t, because otherwise it will snap and its body, in a last, petty act of revenge, will promptly start to putrefy inside you.

There is some good news however. According to the Carter Centre, in 1986 there were around 3,500,000 cases of this disease. By 2011 there were just over a  thousand; and that number represented a massive decline even from 2010. The parasite NEEDS a human host to complete its life-cycle, and so, like smallpox, it can’t really hide in the environment, waiting to re-emerge. Although the target to utterly eradicate the disease by 2009 was missed (http://www.who.int/wer/2010/wer8519.pdf), it seems likely it’ll be accomplished soon. And best of all, a lot of the measures used to combat the worm are far from expensive, and often result in other benefits as well – for example, establishing clean water supplies. Ironically enough, the WHO, which is in charge of eliminating things like this nematode, has as its emblem the asklepian. Which you have to admit is irony. Or karma. Or – something, at any rate.  (And we have to admit we only have the vaguest idea of what ‘irony’, ‘karma’ or anything else actually means).

And you thought there could never be a feel-good story about humanity wiping out an entire species…

WHO Flag

The flag of the WHO basically harks back to a time when the best way to extract parasitic worms from people was to twist them out using small sticks. Frankly, it makes us doubt their medical credentials (Credit: Wikimedia Commons)