AIDS stands for Acquired Immunodeficiency (or Immune Deficiency)
Syndrome. It results from infection with a virus called HIV,
which stands for Human Immunodeficiency Virus. This virus
infects key cells in the human body called CD4-positive (CD4+) T
cells. These cells are part of the body's immune system, which
fights infections and various cancers.
When HIV invades the body's CD4+ T cells, the damaged immune
system loses its ability to defend against diseases caused by
bacteria, viruses, and other microscopic organisms. A
substantial decline in CD4+ T cells also leaves the body
vulnerable to certain cancers.
There is no cure for AIDS, but medical treatments can slow down
the rate at which HIV weakens the immune system. As with other
diseases, early detection offers more options for treatment and
What Is The Difference Between HIV And AIDS?
The term AIDS refers to an advanced stage of HIV infection, when
the immune system has sustained substantial damage. Not everyone
who has HIV infection develops AIDS.
When HIV progresses to AIDS, however, it has proved to be a
universally fatal illness. Few people survive five years from
the time they are diagnosed with AIDS, although this is
increasing with improvements in treatment techniques.
Experts estimate that about half the people with HIV will
develop AIDS within 10 years after becoming infected. This time
varies greatly from person to person, however, and can depend on
many factors, including a person's health status and
People are said to have AIDS when they have certain signs or
symptoms specified in guidelines formulated by the U.S. Centers
for Disease Control and Prevention (CDC).
The CDC's definition of AIDS includes:
All HIV-infected people with fewer than 200 CD4+ T cells per
cubic millimeter of blood (compared with CD4+ T cell counts
of about 1,000 for healthy people)
People with HIV infection who have at least one of more than
two dozen AIDS-associated conditions that are the result of
HIV's attack on the immune system
AIDS-associated conditions include:
by bacteria, fungi, and viruses. Opportunistic infections
are infections that are rarely seen in healthy people but
occur when a person's immune system is weakened.
The development of certain cancers (including cervical
cancer and lymphomas).
Certain autoimmune disorders.
Most AIDS-associated conditions are rarely serious in healthy
individuals. In people with AIDS, however, these infections are
often severe and sometimes fatal because the immune system is so
damaged by HIV that the body cannot fight them off.
The History Of AIDS
The symptoms of AIDS were first recognized in the early 1980s:
In 1981, a rare lung infection called Pneumosystis
carinii pneumonia began to appear in homosexual men
living in Los Angeles and New York.
At the same time, cases of a rare tumor called Kaposi's
sarcoma were also reported in young homosexual men.
These tumors had been previously known to affect elderly
men, particularly in parts of Africa. New appearances of the
tumors were more aggressive in the young men and appeared on
parts of the body other than the skin.
Other infections associated with weakened immune defenses
were also reported in the early 1980s.
Groups most frequently reporting these infections in the early
1980s were homosexuals, intravenous drug users, and people with
hemophilia, a blood disorder that requires frequent
transfusions. Blood and sexual transmission were therefore
suspected as the sources for the spread of the infections.
In 1984, the responsible virus was identified and given a name.
In 1986, it was renamed the human immunodeficiency virus (HIV).
Need To Know:
Because many of the first cases of AIDS in the United
States occurred in homosexual men and intravenous drug
users, some people mistakenly believe that other groups
of people are not at risk for HIV infection. However,
anyone is capable of becoming HIV-infected, regardless
of gender, age, or sexual orientation.
Facts About AIDS
As of the year 2000, nearly one million people in
the U.S. were confirmed to be HIV-positive.
The Centers for Disease Control and Prevention
reports that 2.2 million Americans now carry the HIV
virus but do not yet have symptoms.
Each year, about 40,000 new HIV infections occur in
AIDS is a leading cause of death for American men
and women between the ages of 25 and 44.
Through June 2000, 438,795 people in the U.S. had
died from AIDS (374,422 men and 64,373 women).
By the end of 2000, 36.1 million people worldwide
were living with HIV/AIDS, with the vast majority
living in developing countries.
Through 2000, 21.8 million people worldwide have
died from AIDS.
Between 1991 and 1996, there were more new cases of
AIDS among people older than 50 than those between
ages 13 and 49. Today, 11% of all new cases of AIDS
in the U.S. are now in people over the age of 50.
The HIV carrier rate in the U.S. is now 1 carrier
for every 100 to 200 people.