Soil bacteria may offer drug to treat roundworm

A protein from a soil bacterium used to kill insects naturally on organic crops is a highly effective treatment for intestinal parasitic roundworms, claim scientists.

These parasites, which include hookworms and whipworms, infect about two billion people in underdeveloped tropical regions and are cumulatively one of the leading causes of debilitation worldwide, reports Nature.

The scientists report in the March 2 issue of the open-access journal PLoS Neglected Tropical Diseases, that a crystal protein known as Cry5B produced by the Bt, or Bacillus thuringiensis, bacterium is highly effective at a single dose at curing mammals of intestinal roundworm infections.

Bt is a bacterium famous for its use in agricultural insect control and is the leading biologically produced insecticide worldwide. Bt crystal proteins have been used as insecticides for over five decades and are known to be non-toxic to vertebrates.

The discovery of the crystal protein's effectiveness against parasites was made in a UCSD laboratory that has conducted pioneering studies of Bt crystal proteins such as Cry5B that kill roundworms, instead of insects.

"This bacterium is a natural soil predator of nematodes," says author Raffi Aroian from the University of California, San Diego. "The bacterium can kill the worm," he adds, "and it has a great track record for safety around vertebrates."

"Compared to the best drugs people have developed to treat human parasitic worms, this natural protein is at least three times better," Aroian says.