Parasite Illustration (IMAGE) UT Southwestern Medical Center Caption Trypanosoma brucei is a parasite that causes the deadly sleeping sickness. Scientists have determined the parasite has its own biological clock that makes it more vulnerable to medications in the afternoon. The finding could lead to improved treatment for sleeping sickness and other parasitic diseases. Credit UT Southwestern 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.