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What are HIV and AIDS?

HIV (human immunodeficiency virus) infection has now spread to every country in the world and continues to be a major public-health issue. 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. The scourge of 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. In the United States, approximately 1 million people are currently infected, with about 50,000 new HIV infections per year. Here are a few key facts about the disease:

  • Globally, 85% of HIV transmission is through heterosexual intercourse.
  • In the United States, heterosexual transmission accounts for approximately one-quarter of new diagnoses. Male-to-male sexual contact still accounts for more than 60% of new diagnoses, with intravenous drug use contributing to the remaining cases in the U.S. Because the diagnosis may occur years after infection, it is likely that a higher proportion of recent infections are due to heterosexual transmission.
  • Infections in women have remained stable. Worldwide, almost half of people with HIV are women, whereas in the United States, approximately 20% of new diagnoses are in women.
  • There is good news on one front. 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.
  • There is no cure for HIV infection. However, effective treatment with antiretroviral therapy (ART) can suppress the virus and help people with HIV live healthy and productive lives.

In order to understand HIV and acquired immunodeficiency syndrome (AIDS), it is important to understand the meanings behind these terms and the difference between them:

  • HIV stands for the human immunodeficiency virus. It is one of a group of viruses known as retroviruses. After getting into the body, the virus kills or damages cells of the body's immune system. The body tries to keep up by making new 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.
  • AIDS stands for the acquired immunodeficiency syndrome. HIV causes AIDS and occurs when the virus has destroyed so much of the body's defenses that immune-cell counts fall to critical levels or certain life-threatening infections or cancers develop.
Medically Reviewed by a Doctor on 5/5/2015
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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.

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