Invasion of the Bodysnatchers
Tapeworms can grow to several metres
When Tanya Andrews returned from a recent family holiday in Costa
Rica, she had no idea she had brought back a gruesome
souvenir.
A month later she developed an extremely painful lump on her
head.
At first, she thought she had an abscess, but then it
wriggled.
At the Hospital for Tropical Diseases they recognised the problem
straight away - it was the living maggot larva of a botfly.
While Tanya was enjoying her holiday a mosquito had delivered a
tiny botfly egg onto the surface of her scalp.
The egg hatched into a maggot and burrowed deep inside. Incredibly,
this happens to thousands of people every year.
As we travel to ever more exotic holiday destinations, we are at
the mercy of a whole range of bizarre parasites just waiting to
colonise us.
Strange nosebleeds
The Botfly larva pulled from Tanya's head
Soon after travel writer, Broughton Coburn, returned from Nepal he
began to experience regular, inexplicable nosebleeds.
They continued for three weeks until an embarrassing encounter in a
teashop made him realise that something was seriously wrong.
As he was being served, the waiter took one look at him and fled in
horror.
Broughton chased him down the street urging him to tell him what
was wrong. But the boy would only point, wordlessly, at his
nose.
Broughton returned home and sat in trepidation in front of a
mirror.
His patience was rewarded when a brown worm-like creature emerged
from his right nostril and looked around.
"I swear it had two beady eyes on it. And it came out two or three
inches, looked around and then retracted. I thought it was a dream,
a vision of some sort."
A thirsty aquatic leech
In shock, Broughton rushed off to his doctor who tried to remove
the mysterious creature.
But it wasn't going to give up its home easily.
"He had this thing pulled out eight or ten inches and I'm looking
at it cross-eyed down the end of my nose, and he's looking at it,
he has a look of absolute horror on his face. And the thing came
off. And there was this leech."
Broughton had been invaded by an aquatic leech. It made its move
while he was drinking from a mountain stream.
These thirsty bloodsuckers can drink three times their bodyweight
at each feed and inject an anaesthetic so their victim feels
nothing.
Welcome visitor
But not all parasites are unwanted and uninvited.
As part of a University of Salford experiment to develop a
diagnostic test for beef tapeworm, biologist Mike Leahy volunteered
to grow this gruesome parasite inside his own gut.
Mike swallowed the immature tapeworm cyst with a glass of red wine
and the worm started to grow at an initial rate of four centimetres
a week.
Twelve weeks later he had to call a halt to the unusual experiment
because he was getting married!
The tapeworm cyst that Dr Leahy ate
After a dose of anti-worm pill Mike passed out an intact tapeworm
three metres long.
Disgusted? Well according to Dr Val Curtis, an expert on hygiene,
this reaction is a natural survival mechanism.
"In the same way that you have an immune system which helps to
protect you from parasites we also have a behavioural system.
"When you feel the emotion of disgust it is a driver of your
behaviour to make you keep away from or drop the thing that might
be about to make you sick."
And, it seems, we need all the protection we can get. Every living
thing has at least one parasite and many creatures, including
humans, have far more.
In fact, parasites make up the majority of species on Earth.
