- Who would deliberately drink a dose of gut worms?
The answer is Anna Glanz, an ordinary mother-of-two from Iowa.
- She's testing the remarkable theory that not all
parasites are necessarily bad for us. Some of them may actually help
us fight diseases.
- A BBC documentary looks at how some parasites are so
well-adapted to using humans as hosts, that when you take them away,
there are unexpected results.
- Ulcerative colitis is a disease of the intestine
caused by the immune system over-reacting - in this disease the white
blood cells attack the gut as though it's a foreign invader, making it
- Mother-of-two, Anna Glanz, from Iowa, suffers from
it and gets terrible cramps and sudden, intense attacks of
- The disease is incurable, but she is now taking part
in an experimental trial run by Dr Joel Weinstock, a specialist in
- He's giving her worms to try to treat the
- Drink up
- Every three weeks Anna goes to Dr Weinstock's clinic
and takes a drink full of worm eggs.
- But Anna reckons it is worth it: "I don't really
think of them as being alive I guess, it's almost just like taking a
pill or something.
- "I try not to think of them as disgusting or
anything like that. And I couldn't live the way I was living. I was
desperate to try anything. I just wanted to get well".
- The worms grow inside her gut and then pass out
after a few weeks, but as a result of having these worms in her gut,
her ulcerative colitis is in remission - she doesn't suffer from any
of the symptoms any more.
- Dr Weinstock reckons that's because we've evolved
with worms and actually need them.
- Before gut worms were eradicated in the West 50 or
so years ago allergies - caused by the overreaction of the immune
system - were virtually unheard of, now in the UK one third of us
suffers from some sort of allergy.
- So scientists are looking to see if there's a
connection between gut worms and allergies, they are wondering if gut
worms can somehow damp down the immune system to make it easier for
them to live in the intestine without coming under attack.
- He said: "Worms require humans to survive. In
essence the worms are part of us and it's possible that we've become
interdependent and removing worms has resulted in an imbalance to our
- "People have what I consider an irrational fear of
worms. Nobody wants to go to the toilet and look into the toilet and
see something wiggle".
- On the hook
- Another person feeling the benefit of a worm
infestation is academic researcher Alan Brown, who picked up hookworms
while on a field-trip outside the UK.
- The worm hangs around damp earth or water droplets,
and on contact with skin burrows through and heads for the gut.
- There it attaches itself to the wall - and drinks
blood to live.
- However, in western countries, where people are
well-nourished, a moderate infestation is likely to have no nasty
side-effects at all.
- Dr Brown examines his own faeces under the
microscope to try to guage how many worms currently reside within
- "Given the number of eggs there, there's about 300
hookworms in my guts."
- However, there's a useful effect - his hayfever has
virtually disappeared, and now he is working on the powers of the
hookworm with a view to developing an asthma drug.
- He said: "My wife's horrified - she's totally
convinced that one day I'm going to infect the whole family."
- Mental manipulation
- This may not be the only parasite that changes the
human body to make it easier to survive. And not all those changes may
have potentially beneficial side-effects.
- Some may have developed an extraordinary power to
- One third of Britons carry the toxoplasma parasite
in their brain.
- Its natural home is the cat and it's spread in cats'
faeces. It can be picked up by any mammal, from rats to cattle. The
main way we get it is by eating undercooked meat (which is why 80% of
the French are estimated to have it, with their love of rare
- Once we have it we have it for life, there's no way
we can get rid of it.
- Research shows it somehow manipulates rats'
behaviour - it makes rats attracted to cats - their natural predator,
so they're more likely to be eaten by a cat and the parasite can
complete its life cycle.
- For years scientists thought it had no effect on our
behaviour, but now the parasite's changing their minds. Recent
research suggests that people with toxyplasma have slower reaction
times than those without and are also more than twice as likely to be
involved in a traffic accident than those who aren't carrying the
- © BBC MMIII