HIV & AIDS

Is it possible to deliver a knockout punch to HIV?

With a global focus on strategies to curb expansion of a fast-moving coronavirus pandemic, the question again has arisen: What more is being done about HIV, a scourge that has lasted more than 40 years—is a cure finally ...

Diseases, Conditions, Syndromes

Mpox vaccine found to be protective by CDC

Researchers from the Mpox Emergency Response Team, Centers for Disease Control and Prevention (CDC) in Atlanta have conducted a case-control study based on data from a nationwide electronic health record database, Cosmos, ...

Genetics

CRISPR baby mutation significantly increases mortality

A genetic mutation that a Chinese scientist attempted to create in twin babies born last year, ostensibly to help them fend off HIV infection, is also associated with a 21% increase in mortality in later life, according to ...

HIV & AIDS

Mathematical model seeks functional cure for HIV

(Medical Xpress)—Individuals with the natural ability to control HIV infection in the absence of treatment are referred to as elite controllers (ECs). Such individuals maintain undetectable viral loads less than 50 copies ...

HIV & AIDS

Scientists use stem cells to create HIV resistance

(Medical Xpress)—Yuet Wai Kan of the University of California, San Francisco and colleagues have created HIV-resistant white blood cells by editing the genomes of induced pluripotent stem cells. The researchers inserted ...

HIV & AIDS

Engineered stem cells seek out, kill HIV in living organisms

(Medical Xpress) -- Expanding on previous research providing proof-of-principal that human stem cells can be genetically engineered into HIV-fighting cells, a team of UCLA researchers have now demonstrated that these cells ...

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Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS), a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unsafe sex, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth (perinatal transmission). Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.

HIV infection in humans is considered pandemic by the World Health Organization (WHO). Nevertheless, complacency about HIV may play a key role in HIV risk. From its discovery in 1981 to 2006, AIDS killed more than 25 million people. HIV infects about 0.6% of the world's population. In 2009, AIDS claimed an estimated 1.8 million lives, down from a global peak of 2.1 million in 2004. Approximately 260,000 children died of AIDS in 2009. A disproportionate number of AIDS deaths occur in Sub-Saharan Africa, retarding economic growth and exacerbating the burden of poverty. An estimated 22.5 million people (68% of the global total) live with HIV in sub-Saharan Africa, which is also home to 90% of the world's 16.6 million children orphaned by HIV. Treatment with antiretroviral drugs reduces both the mortality and the morbidity of HIV infection. Although antiretroviral medication is still not universally available, expansion of antiretroviral therapy programs since 2004 has helped to turn the tide of AIDS deaths and new infections in many parts of the world. Intensified awareness and preventive measures, as well as the natural course of the epidemic, have also played a role. Nevertheless, an estimated 2.6 million people were newly infected in 2009.

HIV infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and dendritic cells. HIV infection leads to low levels of CD4+ T cells through three main mechanisms: First, direct viral killing of infected cells; second, increased rates of apoptosis in infected cells; and third, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytes that recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections.

Most untreated people infected with HIV-1 eventually develop AIDS. These individuals mostly die from opportunistic infections or malignancies associated with the progressive failure of the immune system. HIV progresses to AIDS at a variable rate affected by viral, host, and environmental factors; most will progress to AIDS within 10 years of HIV infection: some will have progressed much sooner, and some will take much longer. Treatment with anti-retrovirals increases the life expectancy of people infected with HIV. Even after HIV has progressed to diagnosable AIDS, the average survival time with antiretroviral therapy was estimated to be more than 5 years as of 2005[update]. Without antiretroviral therapy, someone who has AIDS typically dies within a year.

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