HIV is an autoimmune disease caused by a virus that destroys the body's immune system, which is your natural barrier against invading pathogens and other environmental toxins. You can get this infection by contact between HIV-infected blood, broken skin, wounds, and blood-contaminated body fluids. There are various stages of HIV infection; acute infection, latent period and the most severe stage, acquired immune deficiency syndrome or more commonly known as "AIDS". Without treatment, you are at a higher risk of developing the most severe stage (AIDS), which overwhelm your immune system and damages it so badly that chances of getting opportunistic infections by other pathogens are greatly increased.
There are approximately 1.3 million persons aged 14 and older living with HIV and AIDS in the United States alone, including more than 1.6 million clinically undiagnosed cases. Globally, this number has reached 36.7 million infected cases.