Have you ever had that nightmare where there are creepy crawlies in your body? For one unfortunate man, this nightmare became a reality.
In 2008, a man visited a Cambridge hospital complaining of a concoction of maladies: from headaches and seizures, to hallucinated smells and odd flashbacks. A brain scan revealed a cluster of lesions in one side of his brain. Doctors feared this could be a tumour or tuberculosis, but tests from a brain biopsy all came back negative. Having found no explanation for his condition, the doctors had no choice but to send the man home.
Four years later, and fed up with worsening symptoms, the man returned to hospital. The doctors reimaged his brain and found something worrying – the lesions had spread deeper into important brain regions.
His condition was becoming critical and could no longer be ignored, so they re-biopsied his brain, and this time found something shocking – a piece of a worm!
The worm had been living in his brain, causing lesions as it wiggled around. It needed to be removed before it caused more damage, but because of its location it was inoperable. A drug treatment to poison the worm was the only option. The dilemma came with the realisation that this was a rare worm, and different worms need different drug treatments.
Luckily, the piece of worm from the biopsy held the key. A slice of the worm with 40 billionths of a gram of DNA was sent to the Wellcome Sanger Institute in Cambridge, where geneticists could identify the worm by matching its DNA to a tapeworm previously sequenced, and help doctors decide on the best drug treatment.
“We took known or potential drug targets that we’ve already identified in other tapeworms, and had a look for them in the genome of this rare worm,” Hayley Bennett of the Sanger Institute told The Naked Scientists. “If they’re also present in this rare worm, then there might be a potential for drugs that are developed for the common worms to be cross-applied and used for rare infections.”
With this genetic information, doctors could also finally figure out how this man was infected with a rare tapeworm.
“Some of the genes were identical to those isolated from [tapeworm-infected] frogs in Hunan province in China, so that’s a strong candidate for where this particular infection was acquired,” Dr Andrew Dean of Addenbrooke’s neuropathology department concluded.
So, those of us who haven’t been to rural China, where this man visited his family, can breathe a sigh of relief. And in the end, so could this man, as the doctors were able to kill the worm, and in their paper in Genome Biology, they concluded that his brain problems have completely subsided. The dead worm remains in his brain, but will eventually be broken down naturally.
Though his remarkable story ends there, this work could have a long future of helping people.
“Tapeworms are a massive problem worldwide,” Bennett explains. “They’re thought to be the leading cause of epilepsy in the developing world, and by understanding more about them we hope to identify new drug targets and new ways of controlling them.“