Home' Trinidad and Tobago Guardian : January 23rd 2015 Contents A32
body & soul
Guardian www.guardian.co.tt Friday, January 23, 2015
Once you consume them, they can move through-
out your body---your eyes, your tissues and most
commonly your brain. They leave doctors puzzled
in their wake as they migrate and settle to feed on
the body they re invading; a classic parasite, but
this one can get into your head.
"It had moved from one side of the brain to the
other...very few things move in the brain," says Dr
Effrossyni Gkrania-Klotsas about a British man found
to have a tapeworm moving inside his brain in 2013.
This form of tapeworm had never been seen before
in the United Kingdom.
The patient, who was of Chinese descent, had
recently visited China, which along with South Korea,
Japan and Thailand, has more regular occurrences
of the parasite known as Spirometra erinaceieuropaei.
Four years earlier the man had first experienced
symptoms, such as headaches, which the team of
doctors at Addenbrookes Hospital, in Cambridge,
had treated as tuberculosis. But then he returned.
"When he reappeared, he had new symptoms,"
says Gkrania-Klotsas. The worm was now pushing
on a new part of his brain, causing seizures and
weakness in his legs. The condition associated with
his infection was in fact Sparganosis. There is no
known drug to effectively treat the infection meaning
that upon diagnosis doctors had to be quick to remove
the worm surgically.
Just 300 infections of the Spirometra tapeworm
were recorded between 1953 and 2013, but they re
thought to be more common in parts of Asia. The
rural nature of more affected populations means
numbers are widely unknown and very little is known
about the worms.
"These worms are pretty mysterious," says geneticist
Hayley Bennett from the Wellcome Trust Sanger
Institute, in Cambridge, whose team recently
sequenced the genome of the rare worm. "We know
it has a very complicated life cycle."
The adult form of the Spirometra tapeworm only
occurs in the intestines of cats and dogs but as these
animals shed the worms eggs in their feces the eggs
can enter, and contaminate, water. The resulting
juvenile form of tapeworm---known as larvae---can
then stay in the water within certain small crustaceans
or end up in frogs and snakes. As larvae they can
invade humans through ingestion or direct contact
with infected animals. The patient in Cambridge was
thought to have accidentally drunk water whilst
swimming in an infected lake, according to Gkra-
nia-Klotsas. The worm then took hold.
"The larvae can encyst in the brain or somewhere
else," says Bennett. The consequences of these cysts
can be tissue damage, blindness, paralysis or even
death. By sequencing the worm s genes, Bennett
hoped to understand the inner workings of the worms
to aid future diagnosis and treatment.
"Because it s such a rare infection it s not eco-
nomically viable to create a drug just for this worm,"
she explains. "But by comparing it to other tapeworms
we can see which other drugs might apply."
The team were given small samples of the worm,
extracted from the infected patient, and their sequenc-
ing identified an exceptionally large genome and,
importantly, genes which could help recognise resist-
ance to drugs as well as act as future drug targets.
"You could also develop a diagnostic test," adds Ben-
There are many forms of tapeworm, three of which
can readily infect the brain. From a public health
perspective, there s one in particular to watch out
for. "It s mainly the pork tapeworm that s the main
brain one," says Helena Helmby from the London
School of Hygiene and Tropical Medicine.
The pork species, known as Taenia Solium, can
infect humans in two forms. The first is by eating
Worms can invade your brain
undercooked pork from infected
pigs, resulting in taeniasis---an
adult worm residing in the intes-
tine. The second, in the larval
form, through contact with the
feces of an infected pig or human,
which can go on to infect many
tissues. If the larval worm enters
the nervous system, including the
brain, it can result in a condition
known as neurocysticercosis.
Infection of this kind can often
cause epilepsy once inside the
brain. Almost a third of epilepsy
cases in countries where the dis-
ease is native are people who have
previously had neurocysticercosis,
according to the World Health
arises from poor sanitation and
hygiene. "You can actually infect
yourself," says Helmby, as poor
hygiene, such as failing to wash
your hands, could result in you
eating the eggs of an adult worm
living in your intestine. "Self-
infection is common." (CNN.com)
YOUR DAILY HEALTH
News and Advice
Infection of the brain by the larval form of the pork tapeworm
arises from poor sanitation and hygiene, such as failing to
wash your hands.
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