Helminth (image) Washington University School of Medicine Caption Pictured is a helminth parasite. When such a parasite infects mice, some of the signals that the animal's immune system produces to defend against it can activate a latent viral infection. Credit D. Davesne/Wikipedia Usage Restrictions Taken from Wikipedia. For CC BY-SA 3.0 license, go to image. 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.