Opportunistic infection strategy

The human immunodeficiency virus (HIV) infects immune cells, impairing their function and eventually destroying cells over time. This gradually weakens the immune system and the body loses the ability to fight disease. While HIV is the culprit, most people who die of AIDS do not die of HIV, per se, but from the numerous infections that the body can no longer control due to the collapse of the immune system. Relatively common infections, which may cause little or no harm in a healthy person, take the opportunity provided by weakened immune defenses to cause disease. This is why they are called opportunistic infections (OIs).