Article posted Wednesday, December 10, 2014 4:39pm

A nasty intestinal parasite found in humans literally bites pieces out of intestinal cells and ingests them. In this way, intestinal cells are “nibbled” to death, and the effect on the person is massive diarrhea and possible death. “Amoebic Dysentery” killed thousands during the Civil War and in prison camps in World War II and Vietnam. The culprit is a one-celled animal, a protozoan, called Entamoeba histolytica. Common worldwide, especially in areas having poor sanitation, it is estimated that 50 million people harbor the amoeba, which causes from 50 to 100 thousand deaths annually. For years it was thought that E. histolytica released toxins that killed intestinal cells, but recent studies show that the amoebae bite and eat pieces of these cells. Researchers at the Univ. of Virginia placed one amoeba in a culture dish with five (cultured) intestinal cells. This was repeated many times. Using microscopes, the researchers watched what happened. The amoeba attached to an intestinal cell and proceeded to nibble away and ingest pieces of it. When one cell was destroyed, the amoeba moved on to the next. In an infected person, diarrhea is the result, as E. histolytica reproduces rapidly and produces infectious cysts that are released in feces. When an infected person lives close to others under unclean conditions, chances are good that otherwise healthy individuals accidentally ingest cysts and become infected – and they end up with massive diarrhea, loss of fluids, and possible death. (Nature, April 10, 2014; The Scientist Magazine, April 9, 2014)