treatment the infection can interfere with the immune system, and eventually progress to AIDS, sometimes taking many years. Following initial infection an individual
immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive
be transmitted both vertically and horizontally. Mixed-mode transmission can allow symbionts to have the "best of both worlds" – they can vertically infect
infect the anus and genitals. Risk factors for persistent infection by sexually transmitted types include early age of first sexual intercourse, multiple