HIV
hideHuman 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.
For more information about HIV, read the full article at
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News tagged with hiv infection
Shape of things to come: Structure of HIV coat could lead to new drugs
Medicine & Health / HIV & AIDS
Nov 12, 2009 |
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Structural biologists at the University of Pittsburgh School of Medicine have described the architecture of the complex of protein units that make up the coat surrounding the HIV genome and identified in it a "seam" of functional ...
Scientists explain binding action of 2 key HIV antibodies; could lead to new vaccine design
Nov 09, 2009 |
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A very close and detailed study of how the most robust antibodies work to block the HIV virus as it seeks entry into healthy cells has revealed a new direction for researchers hoping to design an effective vaccine.
AIDS experts say Russia needs new HIV strategy
Medicine & Health / HIV & AIDS
Oct 28, 2009 |
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(AP) -- AIDS experts urged Russian officials on Wednesday to scrap their abstinence-based strategy for curbing the spread of HIV, saying the country's fast-growing epidemic could be entering a dangerous new phase.
AIDS: Are the wilderness years over for vaccine research?
Medicine & Health / HIV & AIDS
Oct 21, 2009 |
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Scientists looking for a vaccine against the AIDS virus can be forgiven for wondering at times whether they made the right career decision.
Full results show AIDS vaccine is of modest help
Medicine & Health / HIV & AIDS
Oct 20, 2009 |
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(AP) -- Fresh results from the world's first successful test of an experimental AIDS vaccine confirm that it is only marginally effective and suggest that its protection against HIV infection may wane over time.
AIDS: Vaccine shows positive results in small trial - researchers
Medicine & Health / HIV & AIDS
Oct 19, 2009 |
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An HIV vaccine tested in Tanzania has shown positive results in preliminary trials and may provide better protection than a promising Thai vaccine unveiled on September 24, Swedish researchers said Monday.
Continuing racial differences in HIV prevalence in US
Medicine & Health / HIV & AIDS
Oct 06, 2009 |
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HIV prevalence among African Americans is ten times greater than the prevalence among whites. This racial disparity in HIV prevalence has persisted in the face of both governmental and private actions, involving many billions ...
Volunteers key to success of Thai vaccine trials
Medicine & Health / HIV & AIDS
Sep 28, 2009 |
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(AP) -- Nearly 16,000 Thais ignored the false rumors that they were being infected by the AIDS virus, and overcame their fears of becoming social outcasts to participate in the first HIV vaccine trials to ...
The difficult Way to HIV Vaccine
Medicine & Health / HIV & AIDS
Sep 16, 2009 |
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T cells are key players in the immune response to HIV, which are able to delete infected cells. This capacity is used for vaccine development against HIV. “To date however, success of this strategy remains elusive. Our understanding ...
Making bacteria make useful proteins
Sep 07, 2009 |
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By adapting a single protein on the surface of the bacterium Caulobacter crescentus, researchers at the University of British Columbia have turned it into a protein production factory, making useful proteins that can act as ...
High HIV infection rate among Soweto Township gays
Medicine & Health / HIV & AIDS
Aug 31, 2009 |
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New research from UCSF examining HIV among men who have sex with men (MSM) in the township of Soweto in South Africa has found that a third of gay-identified men are infected with HIV.
Updated guidelines highlight primary care needs of those living with HIV
Medicine & Health / HIV & AIDS
Aug 13, 2009 |
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With HIV patients living longer thanks to advances in treatment, the primary care needs of those living with HIV have never been more important. Updated, evidence-based guidelines from the HIV Medicine Association (HIVMA) ...
Gorillas are new source of HIV, scientists reveal
Medicine & Health / HIV & AIDS
Aug 02, 2009 |
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(PhysOrg.com) -- Scientists have discovered that gorillas are a source of human immunodeficiency virus type 1 (HIV-1), having diagnosed a Cameroonian woman living in Paris with a strain that is different to those previously ...
Scientists learn why even treated genital herpes sores boost the risk of HIV infection
Medicine & Health / HIV & AIDS
Aug 02, 2009 |
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New research helps explain why infection with herpes simplex virus-2 (HSV-2), which causes genital herpes, increases the risk for HIV infection even after successful treatment heals the genital skin sores and breaks that ...
AIDS patients face higher risk of HPV-related cancers as immunosuppression grows
Jul 31, 2009 |
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Risk of human papillomavirus (HPV)-associated cancers is greater for people living with AIDS and increases with increasing immunosuppression, according to a new study published online July 31 in the Journal of the National Ca ...
