Head Louse Versus Body Louse (image) University of Illinois at Urbana-Champaign Caption The human head louse, left, and body louse, right, are the same species, but differ in their ability to transmit disease to their host. Researchers now think they know why. Credit Centers for Disease Control and Prevention Usage Restrictions None 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.