The crystal protein Cry5B is derived from the soil bacterium Bacillus thuringiensis and had previously been shown to be toxic to hookworms with laboratory tests showing Cry5B triggers stress-response pathways in hookworm (Ascaris spp) larvae and adults similar to that observed with other worms.
Now, work feeding two moderate doses of the protein Cry5B to pigs shows nearly complete elimination of intestinal Ascaris. suum infection, US Agricultural Research Service microbiologist Joseph Urban says.
The dose was comparable to that used in existing commercial antiparasitic drugs. Urban, who worked with researchers Raffi Aroian and Yan Hu from the University of California-San Diego, says Cry5B has “potential for use where worm resistance is becoming a problem, especially among ruminant livestock.”
It also has potential in humans as Ascaris suum is genetically so similar to the parasitic roundworm A. lumbricoide, which infects about one billion people a year worldwide, that some evidence suggests they are the same species.
“These results show the potential of Cry5B to treat Ascaris infections in pigs and other livestock and to work effectively in the human gastrointestinal tract.”
A patent protein expression has been applied for and further research with ARS is being planned.
