Burrowing through the skin and internal organs, gnathostoma worms can eventually cause paralysis and death.

After eating some raw sushi, a woman begins a fight for her life as a mass containing parasitic worms creates a blockage in her colon. The woman has Anisakiasis, a disease caused by Anisakis worms.

A young woman contracts a parasite, Trichinella spiralis, after eating infected meat. The condition, called trichinosis, can cause paralysis as the worms burrow through her muscles.

The Leishmania parsite feeds directly on the vital organs from the inside-out. It's spread through infected sand flies.

While swimming with a friend a man has a seizure and collapses. Shortly after, he finds out that a pork tapeworm has been slowly eating away at his brain!

Anisakis worms, common in marine mammals, don't fair so well in the human body. The dead worms can create an inflammatory condition in the gut called Anisakiasis.

The pork tapeworm is a particularly vicious parasite because it can end up in the most important organ in the human body: the brain.

Found inside undercooked wild game and pork, Trichanella spiralis is a parasitic worm that can cut through human muscles and tissue.

Acanthamoeba is a voracious parasite that enters the body through the skin or the nose, then devours brain cells.

Found in contaminated food and water, Entamoeba histolytica is a parasite that feeds on living cells in the human gut.

What happens when humans fall prey to parasites? Explore the shocking, gruesome and sometimes deadly details of parasitic infection on Monsters Inside Me. Returns Friday, Oct. 5 at 8PM E/P!

Even dead, the larvae of parasitic roundworms can cause river blindness, or Onchocerciasis. These parasites are transmitted through the saliva of blackflies.

Unclean sheets and linens carry human scabies mites, which feed on human skin, causing intense itching. The condition is called scabies, or simply "the itch."

Armed with jagged teeth used to hook onto its host, the hookworm can be transmitted from your household cat onto a human.

Some of the most horrifying creatures on the planet are ones that are too small to see! Get a glimpse of these monsters in the new show "Monsters Inside Me", premiering Wednesday, July 1 at 9 p.m. only on Animal Planet!

After taking a trip to a local water park, a man is fighting for his life while a parasite eats his intestines from the inside out.