These Worms Do Invade Brains

 A Chinese descent, based in UK 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 when he returned, this is what one of the doctors had to say, "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. 

"These worms are pretty mysterious," says geneticist Hayley Bennett from the Wellcome Trust Sanger Institute, in Cambridge, "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 Gkrania-Klotsas. The worm then took hold.

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.

"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.