Illustration of a model for the basic structure of the Human Immunodeficiency Virus (HIV), the causative agent of AIDS (Acquired Immune Deficiency Syndrome). A map of the world showing regions with a high incidence of AIDS in yellow is superimposed over the protein core shell. The spherical viral membrane (orange) is studded with glycoprotein (green) and HLA antigens (red). The core contains the vital genetic information for the replication of the virus in form of RNA and the enzyme reverse transcriptase that transcribes the viral RNA into DNA for the purpose of subverting the host cell's genetic material. Purple & pink background.