Vital Signs is a monthly program bringing viewers health stories from around the world.

(CNN) Once you consume them, they can move throughout 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.

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