Amebiasis is an infection of the GI tract. Your GI tract is also known as your gastrointestinal tract. It is made up of your mouth, swallowing tube, called the esophagus, stomach, small and large bowels, and anus. This infection is caused by a parasite. A parasite is a bug or worm that you have taken in your body, most likely through food or water that was in contact with the bug or worm. When you have this illness, it stays in your large bowel and makes you sick. Your bowel may swell and you will have loose stools. Most often, this parasite is found in countries with poor sources of drinking water. You may get this illness from drinking infected water. You can also get it from some other person who has the disease.