Acquired immune deficiency syndrome, or AIDS, is an autoimmune disease
that is the final stage of human immunodeficiency virus, or HIV, which attacks
the immune system similar to other autoimmune diseases and leaves the body
susceptible to other diseases and infections.
HIV and AIDS are often referred to interchangeably, but AIDS is much
more severe and appears much further along in the disease process. However,
because transmission of HIV leads to AIDS, it is important to note that HIV may
be transmitted through sexual contact, body fluid contact or from mother to
Those with HIV may have the disease for 10 years or more before AIDS
symptoms develop. However, if HIV goes untreated, AIDS may develop more
quickly. Untreated HIV usually progresses to AIDS within 10 years. Symptoms of
AIDS include chills, fever, sweats (particularly at night), swollen lymph
nodes, weakness and weight loss. Because of the weakened immune system,
opportunistic infections may develop and be a sign of the onset of AIDS.
There is currently no cure or treatment for AIDS. However, effective
treatment of HIV may stave off or prevent AIDS from developing. HIV is treated
with some combination of a class of drugs known as antiretroviral therapy (ART,
or ARV) or highly active antiretroviral therapy (HAART)
The transition from HIV to AIDS is measured by CD4 cell counts and HIV
ribonucleic acid (RNA) level. CD4 cells are T cells of the immune system, and
AIDS is defined by CD4 levels of less than 200 cells/mcL. HIV RNA level, also
known as viral load, increases as CD4 cell counts decrease.
AIDS is the sixth-leading cause of death among Americans aged 25 to 44
years. In 1995, it was the leading cause of death among those in that age
The World Health Organization estimates that more than 25 million have
died of AIDS since it was discovered in 1981. Estimates from 2008 indicate that
approximately 33.4 million have HIV or AIDS worldwide. Children aged younger
than 15 years account for 2.1 million of those cases.
Additional information about AIDS may be found at these websites: