how does hiv cause aids what causes it
Human immunodeficiency virus, or HIV, is the virus that causes acquired immune deficiency syndrome (AIDS). The virus weakens a person's ability to fight infections and cancer. People with HIV are said to have AIDS when they develop certain infections or cancers or when their CD4 count is less than 200.
How Does HIV and AIDS Cause Illness? HIV attacks and destroys a type of white blood cell called a CD4 cell, commonly called the T-cell. This cell's main function is to fight disease. When a person's CD4 cell count gets low, they are more susceptible to illnesses. AIDS is the more advanced stage of HIV infection.