Each day, billions of new CD-4 cells are produced, and the virus destroys them. This can go on for years, but sooner or later the balance of power between the immune system and the virus begins to change. When that happens, the immune system loses its ability to fight off other infections, many of which a healthy immune system could repel. Many patients do not know they are infected with HIV until that begins to happen. Doctors often diagnose AIDS by the appearance of what are called AIDS-defining illnesses.
Tests can determine the viral load, the level of the virus in a patient's body.
A very low level of CD-4 cells is diagnostic, and so is the presence of HIV antibodies. Tuberculosis, once thought to be virtually eliminated in most countries, is a problem again because HIV has ravaged the immune systems of so many people. Other sexually transmitted diseases are common in places where the HIV rate is high. This information is not intended to be a substitute for professional medical advice. You should not use this information to diagnose or treat a health problem or disease without consulting with a qualified healthcare provider.