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HIV/AIDS

What Are HIV and AIDS?

  • HIV (human immunodeficiency virus) is a virus that most likely mutated decades ago from a virus that infected chimpanzees to one that infects humans. It began to spread beyond the African continent in the late 1970s and is now endemic worldwide. HIV causes disease because it attacks critical immune defense cells and over time overwhelms the immune system.
  • Without treatment, HIV infection starts to cause symptoms in an average of eight to 10 years with opportunistic illnesses, or diseases that only cause illness in people with impaired immune function. This symptomatic phase has been referred to as acquired immune deficiency syndrome (AIDS) or HIV disease.
  • HIV is a lifelong infection, but it is treatable and can be controlled with medications. With consistent treatment using highly specialized antiviral medications, a person with HIV may live about as long as an uninfected person.
  • Statistics show that approximately 40 million people are currently living with HIV infection, and an estimated 40 million have died from this disease since the beginning of the epidemic. HIV has been particularly devastating in sub-Saharan Africa, which accounts for almost 70% of new HIV infections globally. However, infection rates in other countries also remain high.
  • Globally, 85% of HIV transmission is through heterosexual intercourse.
  • Worldwide, almost half of people with HIV are women, whereas in the United States, male-to-male sexual contact still accounts for more than 60% of new diagnoses.
  • Approximately 20% of new diagnoses are in women. In the United States, heterosexual transmission accounts for approximately one-quarter of new diagnoses, with intravenous drug use contributing to the remaining cases in the U.S.
  • Among men who have sex with men, young African-American men are most burdened, followed by Hispanic-American men.
  • Infections in women have dropped 40% since 2005 in the U.S., and new HIV infections in U.S. children have fallen dramatically. This is largely a result of testing and treating infected mothers, as well as establishing uniform testing guidelines for blood products.

HIV is one of a group of viruses known as retroviruses. After getting into the body, the virus enters many different cells, incorporates its genes into the human DNA, and hijacks the cell to produce HIV virus. Most importantly, HIV attacks cells of the body's immune system called CD4 or T-helper cells (T cells). These cells are destroyed by the infection. The body tries to keep up by making new T cells or trying to contain the virus, but eventually the HIV wins out and progressively destroys the body's ability to fight infections and certain cancers. The virus structure has been studied extensively, and this ongoing research has helped scientists develop new treatments for HIV/AIDS. Although all HIV viruses are similar, small variations or mutations in the genetic material of the virus create drug-resistant viruses. Larger variations in the viral genes are found in different viral subtypes. Currently, HIV-1 is the predominant subtype that causes HIV/AIDS. HIV-2, another form of HIV, occurs almost exclusively in West Africa.

Medically Reviewed by a Doctor on 8/24/2016

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HIV/AIDS

HIV Testing

What is HIV Testing?

Human immunodeficiency virus (HIV) is the virus that causes acquired immune deficiency syndrome (AIDS). HIV destroys the body's immune system and eventually leads to AIDS. People with AIDS develop many diseases and "opportunistic" infections (such as pneumonia, tuberculosis, cancer, and skin infections) that may ultimately lead to death. Prevention is critical. There is no cure for HIV/AIDS, but currently, there are effective treatments that can drastically slow the disease process. If you have been exposed to the HIV virus in any number of ways, you can very easily be tested to determine whether or not you have been infected with the virus.


Read What Your Physician is Reading on Medscape

HIV Disease »

Human immunodeficiency virus (HIV) disease was first described in 1981 among 2 groups—one in San Francisco and the other in New York City.

Read More on Medscape Reference »


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