These terms all mean the same thing. While the virus itself is not a disease, it progressively damages the body's immune system. This puts you at risk for developing illnesses you wouldn't otherwise get. There is no cure. Once you've been infected, you have it for life.
Viruses tend to be specialists.
They zero in on a few particular types of cells in the body and move in. The human immunodeficiency virus is best known for targeting the T cells of the immune system. However, it can also attack cells of the brain, nervous system, digestive system, lymphatic system, and other parts of the body. The immune system is made up of specialized cells in the bloodstream that fight off invading germs to keep the body healthy. These white blood cells identify invaders and give orders to soldier-type cells, which then battle various bacteria, viruses, cancers, fungi, and parasites that can make a person sick.