[typoon]

http://www.foxnews.com/story/0,2933,200048,00.html

Monday, June 19, 2006
By Jennifer Warner


Comparing dirty, wild rats and mice to their squeaky-clean laboratory-bred counterparts may help explain why people who live in industrialized societies have higher rates of allergy and autoimmune diseases than those who live in less developed areas.

A new study comparing the rodents provides new evidence that supports this “hygiene hypothesis”, which holds that people who live in “hygienic” societies have higher rates of allergy and possibly autoimmune diseases because their immune systems have not been as challenged by everyday germs and microbes.

The study showed that wild rats and mice had higher levels of two types of antibodies normally associated with triggering allergies and autoimmune diseases in laboratory animals. But in the wild, these antibodies appeared to have a protective effect and defend the animals against potential threats.

Researchers say up to 50 million Americans suffer from allergies and another 8 million have some form of autoimmune disorder, such as lupus, type 1 diabetes, or rheumatoid arthritis. Autoimmune disorders occur when an overactive immune system attacks tissues in the body.

Rats Support Hygiene Hypothesis

Although the hygiene hypothesis has been widely accepted, researchers say it has not been thoroughly tested in animal studies.

"Laboratory rodents live in a virtually germ- and parasite-free environment, and they receive extensive medical care -- conditions that are comparable to what humans living in westernized, hygienic societies experience," says researcher William Parker, PhD, an assistant professor of experimental surgery at Duke University Medical Center, in a news release. "On the other hand, rodents living in the wild are exposed to a wide variety of microbes and parasites, much like humans living in societies without modern health care and where hygiene is harder to maintain."

In the study, published in the Scandinavian Journal of Immunology, researchers compared levels of various antibodies associated with allergies and autoimmune diseases known as immunoglobulins (Ig) in trapped wild rats and mice and those bred in Duke University’s animal facilities. When an animal’s immune system encounters a foreign invader, it responds by producing these antibodies, which bind to the invader and destroy it.

The results showed that the wild rodents had higher levels of two classes of immunoglobulins, IgG and IgE. IgG is often involved in autoimmune disease, and IgE is often implicated in human allergic reactions and plays an important role in fighting against parasites.

Researchers say they expected the wild rodents to have higher levels of IgE because they would have encountered more threats in the wild. But the production of an unusual type of IgG was unexpected.

This polyreactive, autoreactive type of IgG is usually associated with another class of antibodies and it appeared to have a beneficial effect on the wild rodents.

"These results appear to demonstrate that the environment has profound effects on the production of IgE and autoreactive IgG," says Parker. "While the production of these two antibody types lead to autoimmune disease and allergy, respectively, in the laboratory animals, their production seemed to represent a nonpathogenic, protective response to the environment by the wild rodents."

By Jennifer Warner, reviewed by Louise Chang, MD

SOURCES: Devalapalli, A. Scandinavian Journal of Immunology, 2006 online early edition. News release, Duke University Medical Center.

[Dakar]

I've heard of this.

Hell, Star Trek did an episode like this.

[Mastrap]

When I was little we were allowed to help ourselves to vegetables from the veggie garden (I grew up on a farm). We washed these in the trough the horses drank from. When my mother reacted horrified to this my grandmother calmed her down by assuring her that she, as a kid, had done the same and that it was good for the immune system.

I get incredibly annoyed by all the cleaning product advertising on TV claiming that the products kill 99.9% of all germs.

[Monique]

I know, I know, let's see uhmm.

Human and rats are 2 different species.

Maybe rats can operate with dirty hands and nothing happen, but when surgeons operate with dirty hands and no gloves they cause infections.

But, I agree with one thing people are too afraid of germs nowadays. What is wrong with the simple flu once in a while, not fun but you recover easyly from it.

And the more basic germs you are exposed to the better your imune system will work to fight disease.

[typoon]

Surgery is different though. In everyday life though people need germs. Germs are good it gives your immune system practice fighting germs. How else is it going to get practice?

[Eriamjh]

Rats don't do surgery.

Germs are good for you. Sure you get sick every now and then, but then you get better. Allergies never go away!!

[gethigh]

Originally Posted by Monique

Maybe rats can operate with dirty hands and nothing happen, but when surgeons operate with dirty hands and no gloves they cause infections.

Not 100% true. Some hospitals actually have "soap" that is filled with bacteria. Sterilization basically cleans off EVERYTHING leaving the hands easy targets for "bad" bacteria since the "good" bacteria that were keeping the "bad" ones at bay are now gone.

Thus, it depends on what you mean by "dirty," which is a cultural rather than a scientific concept.

[voodoo]

Monique: you are not talking about anything you know. Microecology is perhaps not your .. forté?

That said, the topic has been a hypothesis for decades. Indications are that it is true. The immune system is more likely to develop correctly under stimulus. Lack of stimulus may cause allergy.

Let your kids play in the sandbox and eat the sand. It's good for them

V

[Dork.]

I remember a study that came out not too long ago that said that kids who eat their own boogers have fewer autoimmune disorders like allergies. Yum!

[Yose]

Originally Posted by voodoo

Let your kids play in the sandbox and eat the sand. It's good for them

V

There was a story on the news lately where a child had became infected with roundworm because he played in dirt/sand that had racoon feces in it. If I remember the story properly... he's now paralyzed.

While as a layman on the issue I agree to what you said... there is always the unfortunate exception.

[Yose]

Originally Posted by Dork.

I remember a study that came out not too long ago that said that kids who eat their own boogers have fewer autoimmune disorders like allergies. Yum!

That is what I keep telling my girlfriend!

:sigh:

P.S. I remember that study too.

[Salty]

I heard this suggested somewhere else a while ago. It makes sense. I fortunately don't have any allergies!

[Person Man]

Originally Posted by Dork.

I remember a study that came out not too long ago that said that kids who eat their own boogers have fewer autoimmune disorders like allergies. Yum!

Allergies are NOT autoimmune disorders. BIG difference.

[- - e r i k - -]

I have a very real life example of this. My aunt used to be a hygiene nut. She once scolded me for flushing after I had washed my hands. I stopped using hand soap when I was around 9-10 (something I heard on the radio back then).

My cousins, all three of them, have now a very weak immune system and is constantly sick. I, on the other hand, never ever get sick.

[cjrivera]

Originally Posted by Dork.

I remember a study that came out not too long ago that said that kids who eat their own boogers have fewer autoimmune disorders like allergies. Yum!

... but are more likely to suffer from epistaxis.