Karena Nguyen, Emory Health Sciences (IMAGE) Emory Health Sciences Caption Karena Nguyen in the Emory biology lab with two freshwater snails that serve as intermediate hosts for the parasites that cause schistosomiasis. Credit Rachel Hartman Usage Restrictions Must include credit 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.