An Illustration of Human Immunodeficiency Virus (HIV). (image) University of Utah Health Share Print E-Mail Caption The outer shell, called the capsid (yellow and purple) envelopes the viral RNA genome (blue). Credit Janet Iwasa Usage Restrictions With credit Share Print E-Mail 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.