Toxoplasma Parasite (IMAGE) University of Pennsylvania Caption The toxoplasma parasite (in red) doesn't need to infect an immune cell to alter its behavior, according to new Penn Vet research. Simply being injected with a package of proteins by the parasite (indicated by cells turning green) is enough to change the host cells' activity. Credit Courtesy of Hunter Laboratory/University of Pennsylvania Usage Restrictions In context of reporting 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.