In a recent study, researchers found that 20-foot-long tapeworms could be eating holes in your brain without you even knowing.

Brain tapeworms, a parasitic infection of the nervous system, can leave their victims paralyzed, epileptic, or worse, according to Theodore Nash, a doctor at the National Institutes of Health in Bethesda, MD.

Some fall into comas. Some are paralyzed down one side of their body. Others can't walk a straight line, Dr. Nash told Discover Magazine.

Still others come to Nash partially blind, or with so much fluid in their brain that they need shunts implanted to relieve the pressure. Some lose the ability to speak; many fall into violent seizures, Discover added.

While many of the patients experience different symptoms, they all show the same results when Dr. Nash performs MRI scans of their brains.

Looking at an image, one or more whitish blobs are visible. Dr. Nash explains that while some people might mistake these white blobs for tumors, they are in fact brain tapeworms.

A blob in the brain is not the image most people have when someone mentions tapeworms. These parasitic worms are best known in their adult stage, when they live in people's intestines and their ribbon-shaped bodies can grow as long as 21 feet, the doctor told Discover.

But as he goes on, Dr. Nash mentions that at 21-feet, the tapeworm is way past the first stage of the animal's life cycle.

Before the tapeworms become adults, they spend time as larvae in large cysts. And those cysts can end up in people's brains, causing a disease known as neurocysticercosis, Dr. Nash said.

The term Neurocysticercosis refers to tissue infection after exposure to eggs of the pork tapeworm, which can be ingested if a human were to eat undercooked pork.

The specific type of disease is spread through contaminated food and water, and is primarily a food-borne disease.

After ingesting the eggs, they pass through the intestine, into the tissues and migrate to the brain and muscles. It's there that they form cysts that can persist for years.

Nobody knows exactly how many people there are with it in the United States, Nash, who is the chief of the Gastrointestinal Parasites Section at NIH, said of the disease.

The doctor estimates that 1,500 to 2,000 individuals are infected. He even goes on to suggest that the numbers are vastly higher worldwide, but estimates on that big of a scale are harder to make, due to the fact the disease is most common in poorer locations that lack good public-health systems.

According to the research, while the larva is inside the human body, it tends to think that it's insde the pig, and so confusion ensues.

It burrows into the person's bloodstream and gets swept through the body. Often those parasites end up in the brain, where they form cysts, Nash said.

The tapeworms could typically get stuck in ventricles, or fluid-filled cavities in the brain where they will form extensions similar to a grape tree, essentially masking itself from the immune system.

Dr. Nash reported that as the disease is treatable, its only cure, praziquantel, can carry several side effects such as swelling of the brain and seizures down the line.

Researchers are still working on safer treatments.