Human: What are the causes of the AIDS pandemic? Assistant: 
The primary cause of the AIDS pandemic is the human immunodeficiency virus (HIV). HIV is a retrovirus that infects and replicates within cells of the immune system, specifically CD4+ T-cells. When these infected T-cells are not destroyed by the body's natural defenses, they can become dormant for long periods of time before eventually becoming active again and producing more viruses. This process is known as viral latency. When the virus becomes active again it can spread to other cells, including those in the bloodstream, where it can then be transmitted to others through sexual contact, sharing needles, or from mother to child during pregnancy.