Try this format on the Harmonious Parasites ( messes up t he full link)

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IDEA LAB; The Worm Turns

By MOISES VELASQUEZ-MANOFF

Published: June 29, 2008

In the early 1990s, Weinstock, a gastroenterologist, encountered

a puzzle. The prevalence of inflammatory bowel disease (I.B.D.)

across North America increased markedly during the 20th century. Many

thought that ''bad'' genes would eventually explain the spike, but

Weinstock didn't buy it. In areas where fewer than two generations

ago the I.B.D. incidence might have been as low as 1 in 10,000, it

was now 1 in 250. A defective gene couldn't spread that quickly, he

reasoned. It had to be something in the environment. But what?

Stumped, Weinstock tried turning the question around. Instead of

asking what triggered I.B.D., he asked what, before the 20th century,

protected against it?

At the time, Weinstock, then at the University of Iowa, was editing a

book on parasitic worms. These worms, or helminths, have a

paradoxical effect on the host. Rather than induce inflammation,

which is the body's typical response to invasion, the intruders calm

the host immune system. They force a peace, scientists think, to

avoid eviction and keep the host -- their home and food source -- as

healthy as possible. As Weinstock considered the I.B.D. puzzle, he

wondered if immune manipulation by worms could incidentally protect

against other diseases.

Comparison of the prevalence of I.B.D. and surveys of worm-

infestation rates revealed a telling pattern. About 10 years after

improved hygiene and deworming efforts reduced worms in a given

population, I.B.D. rates jumped. Weinstock had his hypothesis: after

a long coevolution, the human immune system came to depend on the

worms for proper functioning. When cleaner conditions and new

medicines evicted the worms from our bodies, the immune system went

out of kilter. ''Hygiene has made our lives better,'' says Weinstock,

now at Tufts University. ''But in the process of eliminating exposure

to the 10 or 20 things that can make us sick, we're also eliminating

exposure to things that make us well.''

At the time of Weinstock's initial musings, epidemiologists had

already dubbed this notion ''the hygiene hypothesis'': as improved

hygiene reduced exposure to certain infectious agents, the immune

system began malfunctioning. By the late 20th century, autoimmune

disorders, characterized by the body's defenses attacking some aspect

of the self, had increased markedly, and allergic diseases, defined

by an overblown immune response to nonthreatening substances,

afflicted almost half the people in the developed world.

If eliminating worms led to an increase in disease, could re-

introducing worms actually treat these diseases? In mice, the answer

was yes. Worms were used to ''inoculate'' against mouse asthma, Type

1 diabetes, multiple sclerosis and I.B.D. But how to re-worm humans?

We got rid of them for a reason. Too many worms can lead to anemia or

obstructed bowels. The wrong kind can cause considerable suffering,

even death.

Weinstock spotted a prime candidate on pig farms. Pig farmers are

chronically exposed to Trichuris suis, the pig whipworm, and tolerate

it with no apparent side effects. (This is not the potentially

dangerous worm found in undercooked pork.)

In 2005, he published results from two human studies. After ingesting

2,500 microscopic T. suis eggs at 3-week intervals for 24 weeks, 23

of 29 Crohn's patients responded positively. (Crohn's disease belongs

to the I.B.D. family, which also includes ulcerative colitis.) Twenty-

one went into complete remission. In the second study, 13 of 30

ulcerative colitis patients improved compared with 4 in the 24-person

placebo group.

Scientists around the world are intrigued. Several large studies are

under way. Trials using T. suis eggs on patients with multiple

sclerosis, Crohn's and hay fever are beginning in the United States,

Australia and Denmark, respectively. In Germany, scientists are

planning studies on asthma and food allergies. Other European

scientists, meanwhile, plan to replicate many of these experiments

with Necator americanus, a human hookworm.

When scientists unravel how helminths manipulate the immune system --

work is already under way -- Weinstock foresees new worm-based drugs.

But that may be a long way off, he says. Anyway, the pill approach

risks missing the greater lesson. As he says, ''We're part of our

environment; we're not separate from it.'' It's a simple observation

with profound implications that are changing how scientists view the

human organism. The dawning realization is this: You are not just

your genetic self. You are a community of interacting organisms. This

You ecosystem includes the bacteria that outnumber your genetic cells

by 10 to 1, various fungi, viruses and just maybe a few parasites as

well. Disturb or remove any key player, and the whole system can come

unbalanced.

Here's the actual full link below, but you will have to do some

combining and pasting as dissconnects it for some reason.

http://query.nytimes.com/gst/fullpage.html?

res=9400EEDB1739F93AA15755C0A96E9C8B63 & scp=1 & sq=the%20worm%

20turns & st=nyt

Lyle...

> ==>Hi Lyle. That link doesn't work and I would be interested in

> reading it.

>

> Bee

>