If the HIV infection is not treated with anti-HIV drugs, most people’s immune systems are no longer able to defend the body from pathogens that cause illness. Serious illnesses such as pneumonia, esophagitis (a fungal infection of the esophagus) or certain types of cancer can develop. The nervous system and the brain can also be damaged by HIV. It is only at this stage of the illness that it is called AIDS.
Today, AIDS occurs more and more rarely in countries with good medical care.