Tapeworms may hold the key to a 100% effective unisex contraceptive.

ANDREW SYRED / SCIENCE PHOTO LIBRARY

Story by Lindsay Wu
Rewritten for OnSET by Sarah Wood

Medical science has searched unsuccessfully for years to find a contraceptive that is 100% reliable for women- let alone men. However scientists from Keele University in the UK have found a parasite, Ligula intestinalis that inhabits the intestines of some freshwater carp species and makes the fish infertile.

It seems this intelligent tapeworm has developed a chemical compound as an adaptation for survival. The female freshwater carp has a reproductive strategy called synchronous spawning. This is where one crop of eggs and sperm are produced and spawned at one time after which the fish dies. Thus sexual reproduction in the females of these carp species can kill the fish. The tapeworm ideally needs its host to survive longer to allow itself time to spread. So in order to do this the tapeworm prevents the carp from reproducing by releasing a compound which interferes with the fishes’ pituitary gland and hormone production. The chemical released prevents the sperm and egg production in carp of both sexes and successfully keeps its host alive.

The researchers from Keele University are excited about isolating this compound, as it has the potential for use as a new form of contraception for both men and women. However other researchers have suggested that being able to isolate the compound might be a problem, as it is likely that researchers may be a bit uneasy about deliberately infecting a person with tapeworm.

Feminist Amanda Cooke agrees that getting approval for a parasitic organism might be a tad difficult, although she “would have no problem suggesting a safety study first”.

One man that may be happy being a test subject for this study is biologist Dr Mike Leahy in the UK, who happily grew a 3m long tapeworm in his body for twelve weeks as part of a University of Salford experiment to develop a diagnostic test for beef tapeworm- recently shown in the BBC documentary Body Snatchers.

CHECK OUT RELATED LINKS:
Arme.C (2002) Ligula intestinalis- a tapeworm contraceptive. Biologist (London)Dec;49(6) 265-9 http://news.bbc.co.uk/1/hi/health/2549137.stm
http://aquanic.org/publicat/state/il-in/ces/bidwell.pdf

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