What term is used for the third stage of HIV infection, diagnosed with a low CD4 count?

The third stage of HIV infection is known as AIDS, which stands for Acquired Immunodeficiency Syndrome. This designation occurs when an individual's CD4 count drops below a certain threshold, typically 200 cells/mm³, indicating that the immune system is severely compromised. At this stage, the body becomes highly vulnerable to opportunistic infections and certain cancers that a healthy immune system would normally be able to fight off.

The classification of HIV into stages helps in understanding the progression of the virus and in determining the appropriate treatment and management strategies. The term AIDS not only describes the advanced stage of HIV infection but also encompasses the wide range of symptoms and health issues that can arise due to diminished immune function.

The other options represent different aspects of HIV infection or its early stages and do not accurately reflect the specific criteria and implications associated with a AIDS diagnosis.