Related topics: virus , aids
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
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with hiv
HIV tamed by designer 'leash'
Medicine & Health / HIV & AIDS
Oct 29, 2009 |
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Researchers have shown how an antiviral protein produced by the immune system, dubbed tetherin, tames HIV and other viruses by literally putting them on a leash, to prevent their escape from infected cells. The insights reported ...
Economist argues that public-private partnerships are a must in creating an HIV vaccine
Medicine & Health / HIV & AIDS
Nov 04, 2009 |
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(PhysOrg.com) -- MIT economist Jeffrey Harris argues that while the scientific obstacles to creating an HIV vaccine are great, the lack of commercial incentive poses a major problem.
3 Questions: Jeffrey Harris on why we still don't have an HIV vaccine
Medicine & Health / HIV & AIDS
Nov 04, 2009 |
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While many vaccines used around the world today are produced for profit by commercial firms, the private sector accounts for a tiny fraction of the funding for an HIV vaccine: 4 percent in 2008, down from ...
Scientists reveal a new mechanism that increases atherosclerosis in mice
Nov 05, 2009 |
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(PhysOrg.com) -- For all the good it does, a liver protein that senses and gets rid of drugs and pollutants from our body has a downside. For the first time, it has been shown that when it is chronically activated, ...
Imaging study shows HIV particles assembling around its genome
Medicine & Health / HIV & AIDS
Nov 17, 2009 |
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(PhysOrg.com) -- The genesis of one the planet's most lethal viruses, HIV, has been caught on tape. New imaging experiments show individual HIV genomes -- strands of RNA — docking on the inner membrane of an infected cell ...
Why circumcision reduces HIV risk
Medicine & Health / HIV & AIDS
Nov 24, 2009 |
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The decreased risk of HIV infection in circumcised men cannot be explained by a reduction in sores from conditions such as herpes, according to research published in PLoS Medicine.
Many pregnant women avoid HIV screening in Africa
Medicine & Health / HIV & AIDS
Nov 19, 2009 |
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'Prevention is the best cure' is a common expression, but what happens if preventative measures are not used? A large proportion of pregnant Ugandan women are going out of their way not to be HIV tested, increasing the risk ...
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.
Hoping for a fluorescent basket case: How HIV is assembled and released from infected cells
Nov 12, 2009 |
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Although recent advances have raised hopes that a protective vaccine can be developed, acquired immunodeficiency syndrome (AIDS) remains a major public health problem. Much has been learned about HIV-1, the virus that causes ...
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 ...
HIV vaccine failure probably caused by virus used, says new research
Medicine & Health / HIV & AIDS
Nov 16, 2009 |
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The recent failure of an HIV vaccine was probably caused by the immune system reacting to the virus 'shell' used to transmit the therapy around the body, according to research published today in the Proceedings of the Na ...
Research calls for better assessment of tests for tuberculosis, HIV/AIDS and malaria
Nov 17, 2009 |
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A rapid and accurate diagnosis is the first step towards treatment in the fight against infectious disease. However, a team headed by Dr. Madhukar Pai at the Research Institute of the McGill University Health Centre (RI-MUHC) ...
Immediate, aggressive spending on HIV/AIDS could end epidemic
Medicine & Health / HIV & AIDS
Nov 18, 2009 |
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Money available to treat HIV/AIDS is sufficient to end the epidemic globally, but only if we act immediately to control the spread of the disease. That was the conclusion of a study just published in the open-access journal, ...
New findings suggest strategy to help generate HIV-neutralizing antibodies
Medicine & Health / HIV & AIDS
Nov 19, 2009 |
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New discoveries about anti-HIV antibodies may bring researchers a step closer to creating an effective HIV vaccine, according to a new paper co-authored by scientists at the Vaccine Research Center of the National Institute ...
AIDS research reveals a lack of family-planning programs in Uganda
Medicine & Health / HIV & AIDS
Nov 23, 2009 |
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University of Alberta graduate student Jennifer Heys wants to make her message clear: there needs to be more education in Ugandan communities about contraception.
