HIV & AIDS

Newly discovered immune cells at the frontline of HIV infection

Researchers at The Westmead Institute for Medical Research have discovered brand new immune cells that are at the frontline of HIV infection. Known as CD11c+ dendritic cells, these new cells are more susceptible to HIV infection ...

Medical research

Monkey-infecting virus may provide part of future HIV vaccine

A protein from Simian Immunodeficiency Virus (SIV), which can infect monkeys and apes, has shown promise as a potential component of a vaccine against Human Immunodeficiency Virus (HIV), in a new study from scientists at ...

Diseases, Conditions, Syndromes

Withering away: How viral infection leads to cachexia

Many patients with chronic illnesses such as AIDS, cancer and autoimmune diseases suffer from an additional disease called cachexia. The complex, still poorly understood syndrome, with uncontrollable weight loss and shrinkage ...

HIV & AIDS

Once-per-month HIV drugs on the horizon

An HIV diagnosis was once a death sentence, but now people who receive treatment survive for decades with the disease. Keeping the virus at bay usually requires taking a pill every day, which aside from being inconvenient ...

Immunology

Immunotherapy kicks and kills HIV by exploiting a common virus

In a first on the quest to cure HIV, University of Pittsburgh Graduate School of Public Health scientists report today in EBioMedicine that they've developed an all-in-one immunotherapy approach that not only kicks HIV out ...

HIV & AIDS

A cure for HIV? Feasible but not yet realized

This week a team of scientists and physicians from the U.K. published news of a second HIV positive man, in London, who is in long-term (18-month) HIV remission after undergoing treatment for Hodgkins lymphoma. The unexpected ...

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HIV

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 the immune system begins to fail, leading to life-threatening opportunistic infections. 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 (Vertical 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 now pandemic. From 1981 to 2006, AIDS killed more than 25 million people. HIV infects about 0.6 percent of the world's population. In 2005 alone, AIDS claimed an estimated 2.4–3.3 million lives, of which more than 570,000 were children. A third of these deaths are occurring in sub-Saharan Africa, retarding economic growth and increasing poverty. According to current estimates, HIV is set to infect 90 million people in Africa, resulting in a minimum estimate of 18 million orphans. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but routine access to antiretroviral medication is not available in all countries.

HIV primarily 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: firstly, direct viral killing of infected cells; secondly, increased rates of apoptosis in infected cells; and thirdly, 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.

Eventually most HIV-infected individuals develop AIDS. These individuals mostly die from opportunistic infections or malignancies associated with the progressive failure of the immune system. Without treatment, about 9 out of every 10 persons with HIV will progress to AIDS after 10–15 years. Many progress much sooner. 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 (as of 2005) is estimated to be more than 5 years. Without antiretroviral therapy, death normally occurs within a year.

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