HIV compromises and destroys one’s immune system to such a degree that it can no longer fend off the secondary infections caused by AIDS or the virus itself.
It is spread via sexual activity, blood transfusions or any situation in which one person’s blood enters the body and bloodstream of another person.
Even though AIDS is not airborn, people are fooled into believing they do not or cannot have it if they are symptom-free and therefore can be carriers of this disease, spreading it from partner to partner without once getting tested.
You can live with and still be in a state of being able to spread the disease for over ten years.
The life cycle of AIDS involves the virus entering a host cell or T-cell by rupturing through the outer membrane. Once inside, HIV uses an enzyme to convert the virus's RNA into DNA.
https://www.empowher.com/aids-hiv/content/causes-aids-and-hivaids-life-cycle