The Human Immunodeficiency Virus, or HIV, is a type of virus known as a retrovirus that infects the cells of the human immune system, mainly the CD4-positive T-cells and macrophages. The virus either destroys these cells or impairs their ability to function. Over time, infection with HIV leads to the deterioration of the immune system, or immune deficiency.

The immune system is considered deficient when it can no longer fulfil its role of fighting off infections and diseases. Immuno-deficient people are more susceptible to a wide range of infections, most of which are rare among people with healthy immune systems. Infections associated with severe immunodeficiency are known as 'opportunistic infections' because they take advantage of a weakened immune system.

Acquired Immunodeficiency Syndrome, or AIDS, is diagnosed when a HIV-positive person shows the signs, symptoms, infections, and cancers associated with the deficiency of the immune system. The majority of people infected with HIV, if not treated, develop signs of HIV-related illness within five to ten years. However the time between the initial HIV infection and an AIDS diagnoses can be 10 to 15 years, or sometimes even longer.

 

Antiretroviral therapy, or ART, can slow down the progression to AIDS by decreasing the infected person’s viral load or the amount of HIV present in the body. Currently, antiretroviral therapy is the only known treatment for HIV and AIDS. There is no cure for HIV or AIDS.