Infected intestinal cells (IMAGE) University of California - San Diego Caption During the study, UC San Diego researchers used fluorescence to track viral infection. The image shows roundworm intestinal cells infected with Orsay virus (red) and ZIP-1 protein expression (green, indicated with arrows) that is induced only in the presence of the DRH-1 receptor. Credit Troemel Lab, UC San Diego Usage Restrictions Must be used in conjunction with Nature Communications paper on worm immune response. License Original 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.