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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