Whipworms (IMAGE) University of Nebraska-Lincoln Caption New research may have solved the mystery of why some people struggle to expel parasitic worms that infect the intestines. The study suggests that large groups of worms manage to persist, whereas small groups or lone worms get overwhelmed by the host's immune system. Credit Gabor Racz, Katie Black & Scott Schrage | University of Nebraska-Lincoln Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.