Doctors shocked after finding tapeworm in man's brain

CAMBRIDGE, United Kingdom -- A British man kept having headache after headache, and doctors couldn't figure out what was wrong.

When they finally conducted an MRI, doctors discovered something terrifying: Burrowed in his brain tissue was a tapeworm, and it may have been living there for four years.

CNN reports the man first sought out medical help due to his headaches in 2009. At the time, doctors believed he had tuberculosis.

But as the worm moved over the years, the symptoms changed. In 2013, doctors finally made the horrifying discovery: They diagnosed him with Sparganosis, which is a parasitic infection caused by the tapeworm Spirometra erinaceieuropaei.

"It had moved from one side of the brain to the other," Dr. Effrossyni Gkrania-Klotsas told CNN. "Very few things move in the brain."

Unlike other tapeworm infections, there are no drugs to treat Sparganosis. Doctors had to remove the worm from the man's brain surgically.

So how did it get there?

This type of worm is usually only found in the intestines of dogs and cats. Humans can get infected if they drink water containing tapeworm eggs. But even then, infection is rare. The CNN report notes there have been just 300 recorded humans cases of Spirometra tapeworm infection in humans since 1953.

"These worms are pretty mysterious," geneticist Hayley Bennett told CNN. "We know it has a very complicated life cycle."

There are other two other species of tapeworm that can also infect the human brain. The most common is Taenia Solium. It gets into your brain from eating or mishandling undercooked pork from infected pigs.