Researchers observed a parasitic infection that essentially "nibbles" human cells to death.

In the past the amoeba, dubbed Entamoeba histolytica, was believed to have killed its target cells before engulfing and consuming them, a University of Virginia news release reported via PR Newswire. The researchers now believe the amoeba takes small bites of the cell "like a piranha" until it dies, and then leaves the deceased remains behind.

"This is the first demonstration that nibbling can serve as a way to kill other cells. The findings suggest that amoebae might invade and destroy host intestinal tissue by nibbling alive the cells that line the gut," UVA researcher Katherine S. Ralston, PhD, said in the news release. "Intriguingly, there are hints that organisms can also nibble. Perhaps this process is more common than we realize, and it is taken to the extreme in the case of the amoebae, which use nibbling to kill."

Entamoeba histolytica is extremely dangerous because it can cause "potentially fatal diarrhea," the news release reported.  The parasite is especially prevalent in the developing world; one third of all infants living in a slum of Bangladesh that the researcher worked in will contract the infection within the first year of their life.

The amoebae colonize and begin to nibble away at nearby human cells; the infection can be asymptomatic, but can also cause "diarrhea, inflammation of the colon, [and[ bowel diseases," the news release reported.

"It has been 111 years exactly since this parasite was named 'histolytica' for its ability to lyse tissues. Finally, the way it kills has been discovered," William A. Petri Jr., MD, PhD, chief of the UVA Division of Infectious Diseases and International Health, said in the news release. "This provides an avenue to explore how best to prevent and treat this parasite that infects up to one of every three children by their first birthday in Bangladesh."  

The report was published in the journal Nature.