HIV is the human immunodeficiency virus. It is the virus that can lead to acquired immune deficiency syndrome, or AIDS. CDC estimates that about 56,000 people in the United States contracted HIV in 2006.
HIV damages a person’s body by destroying specific blood cells, called CD4+ T cells, which are crucial to helping the body fight diseases.
HIV is spread primarily by:
Not using a condom when having sex with a person who has HIV. All unprotected sex with someone who has HIV contains some risk. However:
Unprotected anal sex is riskier than unprotected vaginal sex.
Among men who have sex with other men, unprotected receptive anal sex is riskier than unprotected insertive anal sex.
Having multiple sex partners or the presence of other sexually transmitted diseases (STDs) can increase the risk of infection during sex. Unprotected oral sex can also be a risk for HIV transmission, but it is a much lower risk than anal or vaginal sex.
Sharing needles, syringes, rinse water, or other equipment used to prepare illicit drugs for injection.
Being born to an infected mother—HIV can be passed from mother to child
during pregnancy, birth, or breast-feeding.
The earliest known case of infection with HIV-1 in a human was detected in a blood sample collected in
1959 from a man in Kinshasa, Democratic Republic of the Congo. (How he became
infected is not known.) Genetic analysis of this blood sample suggested that
HIV-1 may have stemmed from a single virus in the late 1940s or early 1950s.
We know that the virus has existed in the United States since at least the
mid- to late 1970s. From 1979–1981 rare types of pneumonia, cancer, and other
illnesses were being reported by doctors in Los Angeles and New York among a
number of male patients who had sex with other men. These were conditions not
usually found in people with healthy immune systems.
In 1982 public health officials began to use the term "acquired
immunodeficiency syndrome," or AIDS, to describe the occurrences of
opportunistic infections, Kaposi's sarcoma (a kind of cancer), and
Pneumocystis jirovecii pneumonia in previously healthy people. Formal
tracking (surveillance) of AIDS cases began that year in the United States.
In 1983, scientists discovered the virus that causes AIDS. The virus was at
first named HTLV-III/LAV (human T-cell lymphotropic virus-type III/lymphadenopathy-associated virus) by an international scientific committee. This name was later
changed to HIV (human immunodeficiency virus).
For many years scientists theorized as to the origins of HIV and how it
appeared in the human population, most believing that HIV originated in other
primates. Then in 1999, an international team of researchers reported that they
had discovered the origins of HIV-1, the predominant strain of HIV in the
developed world. A subspecies of chimpanzees native to west equatorial Africa
had been identified as the original source of the virus. The researchers believe
that HIV-1 was introduced into the human population when hunters became exposed
to infected blood.
stands for Acquired Immunodeficiency
means that the disease is not hereditary but develops after birth
from contact with a disease-causing agent (in this case, HIV).
Immunodeficiency – means that the disease is characterized by a
weakening of the immune system.
Syndrome – refers to a group of symptoms that indicate or characterize a disease. In the case of AIDS, this can include the development of certain infections and/or cancers, as well as a decrease in the number of certain specific blood cells, called CD4+ T cells, which are crucial to helping the body fight disease.
Before the development of certain medications, people with HIV could progress to AIDS in just a few years. Currently, people can live much longer - even decades - with HIV before they develop AIDS. This is because of “highly active” combinations of medications that were introduced in the mid 1990s.
A diagnosis of AIDS is made by a physician using specific clinical or laboratory standards.
Prior to 1996, scientists estimated that about half the people with
HIV would develop AIDS within 10 years after becoming infected. This
time varied greatly from person to person and depended on many factors,
including a person's health status and their health-related behaviors.
Since 1996, the introduction of powerful antiretroviral therapies has
dramatically changed the progression time between HIV infection and the
development of AIDS. There are also other medical treatments that can
prevent or cure some of the illnesses associated with AIDS, though the
treatments do not cure AIDS itself. Because of these advances in drug
therapies and other medical treatments, estimates of how many people
will develop AIDS and how soon are being recalculated, revised, or are
currently under study.
As with other diseases, early detection of infection allows for more
options for treatment and preventative health care.
epidemic of HIV and AIDS has attracted much attention both within
and outside the medical and scientific communities.
Much of this attention comes from the many social issues related to
this disease such as sexuality, drug use, and poverty. Although the
scientific evidence is overwhelming and compelling that HIV is the
cause of AIDS, the disease process is still not completely understood.
This incomplete understanding has led some persons to make statements
that AIDS is not caused by an infectious agent or is caused by a virus
that is not HIV. This is not only misleading, but may have dangerous
consequences. Before the discovery of HIV, evidence from epidemiologic
studies involving tracing of patients’ sex partners and cases
occurring in persons receiving transfusions of blood or blood clotting
products had clearly indicated that the underlying cause of the condition
was an infectious agent. Infection with HIV has been the sole common
factor shared by AIDS cases throughout the world among men who have
sex with men, transfusion recipients, persons with hemophilia, sex
partners of infected persons, children born to infected women, and
occupationally exposed health care workers.
The conclusion after more than 28 years of scientific research is
that people, if exposed to HIV through sexual contact or injecting
drug use for example, may become infected with HIV. If they become
infected, most will eventually develop AIDS.
The only way to know if you are infected is to be tested for HIV infection. You cannot rely on symptoms to know whether or not you are infected.
Many people who are infected with HIV do not have any symptoms at all
for 10 years or more.
The following may be warning signs of advanced HIV infection:
rapid weight loss
recurring fever or profuse night sweats
profound and unexplained fatigue
swollen lymph glands in the armpits, groin, or neck
diarrhea that lasts for more than a week
white spots or unusual blemishes on the tongue, in the mouth, or in the throat
red, brown, pink, or purplish blotches on or under the skin or inside the mouth, nose, or eyelids
memory loss, depression, and other neurological disorders
However, no one should assume they are infected if they have any of these symptoms. Each of these symptoms can be related to other illnesses. Again,
the only way to determine whether you are infected is to be tested for HIV infection.
For information on where to find an HIV testing site,
visit the National HIV Testing Resources Web site or call
CDC-INFO 8A-8P (EST) M-F. Closed weekends and major federal holidays
at 1-800-CDC-INFO (232-4636), 1-888-232-6348 (TTY), in English, en Español.
These resources are confidential. You can also ask your health care provider to
give you an HIV test.
If you would like more information or have personal concerns, call
CDC-INFO 8A-8P (EST) M-F. Closed weekends and major federal holidays
at 1-800-CDC- INFO (232-4636), 1-888-232-6348 (TTY), in English, en Español.
Centers for Disease
Control and Prevention, 1600 Clifton Rd,
Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348,
8A-8P (EST) M-F. Closed weekends and major federal holidays -