http://www.cnn.com/2007/LIVING/personal/08/31/houseguests.hell/index.html?imw=Y&iref=mpstoryemail


When it comes to parasites, it's all about perspective. You may call a lifetime of growing and feeding off another organism lazy, but we call it opportunistic. In fact, these life-sucking go-getters have managed to carve out some of the most ingenious survival strategies in the world.

While reading this article I couldn't help but think of you; in a non-parasitic way mind you :) I also felt my skin crawl more than a time or two.

Considering all the nasty little bugs and slimy critters on the planet, it's a wonder that homo sapiens survives at all....

I'm leaving now... I'm going to find a nice, quiet spot and be totally grossed out...

Wow thats icky!

Wow, I found that rather nifty.
Espically the crab parasite.

<3 fildien :)

Thanks for the link, and nice to see parasites getting some press, although I do find it amusing that they stayed well away from those guests that live... closer to home (one in four of you, if you live in North America, is living with a helminth parasite even as we speak :) ).

I'ver never failed to be amazed at the amazing ingenuity and diversity parasitic organisms show with regard to making a living off their host without causing it excessive pathology (it's a bad thing if your host dies before you can complete your life cycle :) ), avoiding immune detection, and compensating their hosts in wierd ways (such as the tongue example, or boosting the metabolic efficiency of the host as does my primary organism of research, T. crassiceps) for the demands they make on them.

Some of the ways in which parasites complete the life cycle are both ingenious and exploit the behavior of their hosts in amusing ways - I'll give an example. In Southeast Asia, the liver fluke Schistosoma japonicum and S. mekongi are endemic - and have a life cycle involving two or three hosts: a pond snail, a freshwater fish, and us :). Infection of humans typically occurs when metacercariae escaping from the snails penetrate the skin and migrate to the hepatic portal vein to set up housekeeping, where they may persist for 20 years or more, laying eggs which are washed with the feces back into the water supply.

A very valid and efficient strategy for food farming in Southeast Asia is farming fish (which eat said pond snails and are also infected by various helminth parasites, which they can pass on to humans) or crayfish in the rice paddies along with the plants as a way to increase their efficiency. Public sanitation is nonexistant in these areas and the usual way in which people relieve themselves is by drop toilet, which frequently drains right back into said paddy, providing it and the organisms in it with a rich source of nutrients... and parasite eggs :). One of the funniest (in an ironic sense) things my former faculty advisor saw (and photographed) while in Vietnam was one such privy, at the edge of a paddy pond, *with an advertisement for a popular anti-worm medicine plastered on the side of it* :). There are lots of other interesting examples of how we unwittingly aid parasites in their business, and even ways in which the prevalence of parasitic infection has shaped culture, but I could go on even longer than usual about them... :)

Thanks for posting the article, and thoroughly cook your meat, don't walk around barefoot in tropical areas, use mosquito repellent, and avoid step wells, folks :)

Regards,
Nydia

There are lots of other interesting examples of how we unwittingly aid parasites in their business, and even ways in which the prevalence of parasitic infection has shaped culture, but I could go on even longer than usual about them... :)
I'd be interested in reading that, if you find time.

AHHHH! They're in my.... AHHHH!

I'd be interested in reading that, if you find time.

Run for the hills, run for your lives!

I scratched a bit too much during that read.I feel like it's on me. I feel like it's on me!!

I need a tape worm to help me lose weight.

I scratched a bit too much during that read.I feel like it's on me. I feel like it's on me!!

I'm glad I wasn't the only one that was scratching while reading those articles/essays. The thing that really makes my skin crawl is termites. I can't explain it, but when I think about termites, I start itching all over.

"Helminth" is a pretty broad spectrum (just means worms, right?). Is the incidence of infection in North America reduced the further north you go?

I've just got a minute here at the moment, but yes, 'helminths' means worms, and in the context I used it referred to the parasitic cestodes, nematodes, and flukes that infect humans as primary hosts. To answer your question, for *some* helminths (hookworms, trematodes) are largely confined to subtropical and tropical areas of the US/Mexico, but the roundworms, as well as the tapeworms, are ubiquitous. There are 1.5 *billion* Ascaris (a large intestinal roundworm) infections worldwide at any given time, not limited to tropical areas, of about which 200 million are symptomatic, and the estmated prevalence of pinworm infection among US children ranges between 30-80%, with southern and eastern regions having higher prevalence (due to the vulnerability of the eggs to dessication).

In the developing world, and even in the US prior to WW2, parasitic helminths cause/caused a tremendous drain on human capital in the form of malnutrition and subclinical, as well as clinical, morbidity. It has been hypothesized that one of the primary reasons that the South languished for so long after the Civil War (from the 1860s to the 1930s) was due not only due to dietary malnutrition due to a paucity of complete proteins and several key vitamins in the average diet, but due to massive parasite loads of Necator americanus (the hookworm) as well as roundworms, caused by improper sanitation, methods of livestock farming and agriculture at the time, clay soils that resist draining, and permissive temperatures.

I've got to run at the moment, but if that wasn't enough to make your skin crawl (swimmers itch? ;) ), you can find a good primer on all things parasitic helminth here:http://www.path.cam.ac.uk/~schisto/General_Parasitology/Hm.helminths.html

Regards,
Nydia

Oh, I'm late, but edit/addendum: Around the turn of the century, pica (a craving to eat dirt) was a common and widespread phenomenon caused by anemia due to infection with N. americanus. Selling special clays for dietary purposes (discreetly, of course) became quite the boutique industry, with clays from certain parts of Arkansas being particularly prized (I'll find a link I've seen to a vintage ad when I get the chance).