Medical encyclopedia hiv-Asymptomatic HIV infection: MedlinePlus Medical Encyclopedia

HIV is spread primarily by unprotected sex including anal and oral sex , contaminated blood transfusions , hypodermic needles , and from mother to child during pregnancy , delivery, or breastfeeding. During , about Owing to their nonspecific character, these symptoms are not often recognized as signs of HIV infection. Even cases that do get seen by a family doctor or a hospital are often misdiagnosed as one of the many common infectious diseases with overlapping symptoms. Thus, it is recommended that HIV be considered in people presenting with an unexplained fever who may have risk factors for the infection.

Medical encyclopedia hiv

Medical encyclopedia hiv

Medical encyclopedia hiv

Bibcode : PNAS. Retrieved July 26, Medicines used Medical encyclopedia hiv encyclopdia HIV are called antiretrovirals. And many people have no hif when they are first infected with HIV or for years afterward. Rare cancers such as Kaposi's sarcoma also take hold in HIV-infected individuals. You can get HIV testing in most doctors' offices, public health clinics, hospitals, and Planned Parenthood clinics. PLOS Pathogens. Journal of the American Academy of Dermatology. Recommendations from the U. Annual Review of Microbiology.

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Environmental Health Perspectives. In macrophages and cells lacking this molecule, Homer s cummings alternate receptor molecule such as the Fc receptor, or the complement receptor site may be used for entry of HIV. It has a high sensitivity. The provirus may remain dormant in the cell's chromosome for months or years, waiting for the T cell to become activated by the immune system. PMID: www. From the Puget Sound Blood Center. Despite intensive efforts by scientists, the spikes have been slow to reveal their structural and functional secrets. Recent advances are providing the first glimpses of the overall three-dimensional structure of the spiked envelope. In general, a second specimen should be collected more than a month later and retested for persons with indeterminate western blot results. HIV and AIDS HIV infects certain cells and tissues of the human immune system and takes them out of commission, rendering Medical encyclopedia hiv person susceptible to a variety Medical encyclopedia hiv infections and cancers. However, one can also acquire the virus through either intravenous drug use or transfusions.

The current definition of AIDS includes:.

  • Research has shown for both same-sex and opposite-sex couples that HIV is untransmissable through condomless sexual intercourse if the HIV-positive partner has a consistently undetectable viral load.
  • When a person becomes infected with HIV, the virus attacks and weakens the immune system.
  • Human Immunodeficiency Virus HIV is usually spread unintentionally, but in the course of sexual or drug-using conduct that is intentional.

One in 4 people in the U. Search Encyclopedia. You didn't answer this question. The correct answer is. If there's any chance you may be infected with HIV, you should be tested as soon as possible. There are medicines that can help keep the virus in check and keep it from damaging your immune system further. The number of people 50 years and older living with HIV has increased, in part, because of a treatment called highly active antiretroviral medicine therapy.

True B. HIV can be passed from one person to another by shaking hands. You can't get HIV by shaking hands, casually kissing or hugging, or being coughed or sneezed on.

The virus is not passed on from a toilet seat, doorknobs, dishes, drinking glasses, food, or pets. HIV is passed from one person to another through body fluids. These are blood, semen, and vaginal fluids. The virus can be passed on most readily during vaginal, oral, and anal sex if you are not using a latex condom. It is can also be spread by sharing needles, syringes, or both with someone who is infected with HIV.

Others at an increased risk are healthcare workers who can get a stick from a needle containing HIV-infected blood. If you are sexually active, it's important to know your partner's sexual history.

You can't tell by how a person looks whether he or she is infected with HIV. You need to know whether your partner has been tested for HIV, when he or she was tested, and the results. Also ask if your partner has had a number of different sex partners. Ask if your partner has shared needles, including needles for diabetes medicines.

And ask if your partner has had unprotected sex. According to the CDC, if a man has had sex with other men, he should get tested at least once a year. Women should get tested with each new sex partner. Although such questions may be uncomfortable to ask, the information is critical to your health. Before being intimate with a new partner, don't hesitate to insist on an HIV test for a potential partner who has been sexually active or shared needles.

Only drug abusers have to worry about the dangers of sharing needles. HIV can be passed on by anyone sharing a needle.

A person with diabetes who might share a needle to inject insulin or to draw blood to check blood glucose levels is at risk for the virus. The nation's blood supply is screened for HIV, so blood transfusions in the U.

But there is still a slight risk. If you got a blood transfusion between and , before blood was routinely checked for HIV, you should get tested. Also, if you have had an operation or a transfusion in a developing country, no matter what year it was, you should be tested. That's about , Americans. Because many older people don't get routinely tested for HIV, the number may be higher.

People ages 50 and older may not recognize HIV symptoms in themselves because they think that what they are feeling and experiencing is part of normal aging. And many people have no symptoms when they are first infected with HIV or for years afterward. They may even dismiss minor flulike symptoms that can occur several weeks after infection.

Doctors may not think to look for HIV in older adults. Doctors also seldom ask their older patients about their sex lives or their drug use. In turn, older patients are less likely than younger patients to bring up either of these subjects with their doctor. If you are sexually active and worried about HIV, bring up the issue with your healthcare provider. Many older people infected with HIV would rather suffer in silence than tell friends or family about their illness.

Older people with HIV are also less likely to join support groups that could help them cope with their illness. They may have more severe cases of depression in response to a diagnosis of HIV than younger patients. If you get treatment early enough, you can be cured of HIV infection. There is no cure for HIV. Early treatment can help keep the virus in check and help block your condition from advancing to AIDS.

The best treatment is prevention. Don't have multiple sex partners. Make sure your partner is not infected with HIV. If a potential sexual partner has had sex with others or shared needles, insist on an HIV test before becoming intimate. If you don't have this information, you are putting yourself at risk. Use a condom during sex. Don't share intravenous needles.

Morbidity and Mortality Weekly Reports — The sensitivity rating, likewise, indicates that, in 1, test results of HIV infected people, 3 will actually be a false negative result. After PCR amplification is complete, the resulting DNA products are hybridized to specific oligonucleotides bound to the vessel wall, and are then made visible with a probe bound to an enzyme. Most disease cures and treatments that have been discovered during the past years have been based on only limited knowledge of a microbe's ability to causes disease. July 14,

Medical encyclopedia hiv

Medical encyclopedia hiv

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Adaptation to use normal cellular machinery to enable transmission and productive infection has also aided the establishment of HIV-2 replication in humans. A survival strategy for any infectious agent is not to kill its host, but ultimately become a commensal organism. Having achieved a low pathogenicity, over time, variants that are more successful at transmission will be selected.

Entry to the cell begins through interaction of the trimeric envelope complex gp spike on the HIV viral envelope and both CD4 and a chemokine co-receptor generally either CCR5 or CXCR4 , but others are known to interact on the target cell surface.

The first step in fusion involves the high-affinity attachment of the CD4 binding domains of gp to CD4. Once gp is bound with the CD4 protein, the envelope complex undergoes a structural change, exposing the chemokine receptor binding domains of gp and allowing them to interact with the target chemokine receptor.

This loop structure brings the virus and cell membranes close together, allowing fusion of the membranes and subsequent entry of the viral capsid.

After HIV has bound to the target cell, the HIV RNA and various enzymes, including reverse transcriptase, integrase, ribonuclease, and protease, are injected into the cell. They are currently thought to play an important role by transmitting HIV to T cells when the virus is captured in the mucosa by DCs. HIV-1 entry, as well as entry of many other retroviruses, has long been believed to occur exclusively at the plasma membrane.

More recently, however, productive infection by pH -independent, clathrin-mediated endocytosis of HIV-1 has also been reported and was recently suggested to constitute the only route of productive entry.

Shortly after the viral capsid enters the cell, an enzyme called reverse transcriptase liberates the positive-sense single-stranded RNA genome from the attached viral proteins and copies it into a complementary DNA cDNA molecule.

The integration of the viral DNA into the host cell's genome is carried out by another viral enzyme called integrase. These mRNAs are exported from the nucleus into the cytoplasm , where they are translated into the regulatory proteins Tat which encourages new virus production and Rev. As the newly produced Rev protein is produced it moves to the nucleus, where it binds to full-length, unspliced copies of virus RNAs and allows them to leave the nucleus.

Gag proteins bind to copies of the virus RNA genome to package them into new virus particles. Upon infection and replication catalyzed by reverse transcriptase, recombination between the two genomes can occur. This form of recombination is known as copy-choice. Recombination events may occur throughout the genome.

Anywhere from two to 20 recombination events per genome may occur at each replication cycle, and these events can rapidly shuffle the genetic information that is transmitted from parental to progeny genomes. Viral recombination produces genetic variation that likely contributes to the evolution of resistance to anti-retroviral therapy.

Yet, for the adaptive advantages of genetic variation to be realized, the two viral genomes packaged in individual infecting virus particles need to have arisen from separate progenitor parental viruses of differing genetic constitution.

It is unknown how often such mixed packaging occurs under natural conditions. Bonhoeffer et al. In addition, Hu and Temin [76] suggested that recombination is an adaptation for repair of damage in the RNA genomes. Strand switching copy-choice recombination by reverse transcriptase could generate an undamaged copy of genomic DNA from two damaged single-stranded RNA genome copies.

This view of the adaptive benefit of recombination in HIV could explain why each HIV particle contains two complete genomes, rather than one. Furthermore, the view that recombination is a repair process implies that the benefit of repair can occur at each replication cycle, and that this benefit can be realized whether or not the two genomes differ genetically.

On the view that recombination in HIV is a repair process, the generation of recombinational variation would be a consequence, but not the cause of, the evolution of template switching. HIV-1 infection causes chronic inflammation and production of reactive oxygen species. For HIV, as well as for viruses in general, successful infection depends on overcoming host defensive strategies that often include production of genome-damaging reactive oxygen species.

Thus, Michod et al. The final step of the viral cycle, assembly of new HIV-1 virions, begins at the plasma membrane of the host cell. The Env polyprotein gp goes through the endoplasmic reticulum and is transported to the Golgi apparatus where it is cleaved by furin resulting in the two HIV envelope glycoproteins, gp41 and gp The Gag p55 and Gag-Pol p polyproteins also associate with the inner surface of the plasma membrane along with the HIV genomic RNA as the forming virion begins to bud from the host cell.

The budded virion is still immature as the gag polyproteins still need to be cleaved into the actual matrix, capsid and nucleocapsid proteins. This cleavage is mediated by the packaged viral protease and can be inhibited by antiretroviral drugs of the protease inhibitor class.

The various structural components then assemble to produce a mature HIV virion. The classical process of infection of a cell by a virion can be called "cell-free spread" to distinguish it from a more recently recognized process called "cell-to-cell spread". Firstly, an infected T cell can transmit virus directly to a target T cell via a virological synapse. HIV differs from many viruses in that it has very high genetic variability. This complex scenario leads to the generation of many variants of HIV in a single infected patient in the course of one day.

When simultaneous infection occurs, the genome of progeny virions may be composed of RNA strands from two different strains. This hybrid virion then infects a new cell where it undergoes replication. As this happens, the reverse transcriptase, by jumping back and forth between the two different RNA templates, will generate a newly synthesized retroviral DNA sequence that is a recombinant between the two parental genomes.

The closely related simian immunodeficiency virus SIV has evolved into many strains, classified by the natural host species. These hosts have adapted to the presence of the virus, [94] which is present at high levels in the host's blood, but evokes only a mild immune response, [95] does not cause the development of simian AIDS, [96] and does not undergo the extensive mutation and recombination typical of HIV infection in humans.

In contrast, when these strains infect species that have not adapted to SIV "heterologous" or similar hosts such as rhesus or cynomologus macaques , the animals develop AIDS and the virus generates genetic diversity similar to what is seen in human HIV infection. Nef 's function in non-pathogenic forms of SIV is to downregulate expression of inflammatory cytokines , MHC-1 , and signals that affect T cell trafficking.

Without this function, T cell depletion is more likely, leading to immunodeficiency. Co-infection with distinct subtypes gives rise to circulating recombinant forms CRFs.

In , the last year in which an analysis of global subtype prevalence was made, Many HIV-positive people are unaware that they are infected with the virus. Specimens that are repeatedly ELISA-reactive occasionally provide an indeterminate western blot result, which may be either an incomplete antibody response to HIV in an infected person or nonspecific reactions in an uninfected person.

HIV deaths other than U. Although IFA can be used to confirm infection in these ambiguous cases, this assay is not widely used. In general, a second specimen should be collected more than a month later and retested for persons with indeterminate western blot results.

Although much less commonly available, nucleic acid testing e. In these situations, a second specimen is collected and tested for HIV infection. Modern HIV testing is extremely accurate, when the window period is taken into consideration. This gives rise to four possible scenarios:. This research includes behavioral health interventions , such as research into sex education , and drug development , such as research into microbicides for sexually transmitted diseases , HIV vaccines , and anti-retroviral drugs.

Previously it was said the chance of transmission was 'very low' or 'negligible' The 'Swiss Statement'. In total from the four studies, couples were enrolled over four continents and , acts of condomless sex were reported, there were zero phylogenetically linked transmissions of HIV where the positive partner had an undetectable viral load. Our results provide a similar level of evidence on viral suppression and HIV transmission risk for gay men to that previously generated for heterosexual couples and suggest that the risk of HIV transmission in gay couples through condomless sex when HIV viral load is suppressed is effectively zero.

This result is consistent with the conclusion presented by Anthony S. In the beginning, the CDC did not have an official name for the disease, often referring to it by way of the diseases that were associated with it, for example, lymphadenopathy , the disease after which the discoverers of HIV originally named the virus. At the same time, Montagnier's group isolated a virus from a patient presenting with swelling of the lymph nodes of the neck and physical weakness , two classic symptoms of primary HIV infection.

Contradicting the report from Gallo's group, Montagnier and his colleagues showed that core proteins of this virus were immunologically different from those of HTLV-I. Montagnier's group named their isolated virus lymphadenopathy-associated virus LAV.

Both HIV-1 and HIV-2 are believed to have originated in non-human primates in West-central Africa, and are believed to have transferred to humans a process known as zoonosis in the early 20th century. HIV-1 is thought to have jumped the species barrier on at least three separate occasions, giving rise to the three groups of the virus, M, N, and O.

There is evidence that humans who participate in bushmeat activities, either as hunters or as bushmeat vendors, commonly acquire SIV. It is thought that several transmissions of the virus from individual to individual in quick succession are necessary to allow it enough time to mutate into HIV. Specific proposed high-risk transmission channels, allowing the virus to adapt to humans and spread throughout the society, depend on the proposed timing of the animal-to-human crossing.

Genetic studies of the virus suggest that the most recent common ancestor of the HIV-1 M group dates back to circa An alternative view—unsupported by evidence—holds that unsafe medical practices in Africa during years following World War II, such as unsterile reuse of single-use syringes during mass vaccination, antibiotic, and anti-malaria treatment campaigns, were the initial vector that allowed the virus to adapt to humans and spread.

From Wikipedia, the free encyclopedia. Human retrovirus, cause of AIDS. This article is about the virus. For other uses, see HIV disambiguation. For the computer virus, see AIDS computer virus. See also: Subtypes of HIV. Main article: Structure and genome of HIV. Main article: HIV tropism. Further information: Genetic recombination. Further information: Subtypes of HIV. South Africa India Tanzania 4. Mozambique 4. Zimbabwe 3. Cameroon 3. Indonesia 3. Kenya 2. Uganda 2.

Malawi 2. DR Congo 2. Ethiopia 2. Other Medicine portal Viruses portal. Bibcode : Sci Annual Review of Medicine. Retrieved March 12, The Lancet. Desrosiers RC ed. PLOS Pathogens. Oxford: Oxford University Press. Environmental Health Perspectives. Archived from the original on 6 November May 15, Retrieved December 8, This article incorporates text from this source, which is in the public domain.

Current Opinion in Microbiology. Bibcode : Natur. Robbins Basic Pathology 9th ed. National Institutes of Health. Retrieved February 28, ACS Chemical Biology.

Cold Spring Harbor Perspectives in Medicine. Statistics in Medicine. Journal of General Virology. Journal of Medicinal Chemistry. Lippincott's Illustrated Reviews: Microbiology. Lippincott's Illustrated Reviews. Retrieved March 31, May 27, Archived from the original on February 19, Retrieved September 14, Cell Reports. Nature Communications. Bibcode : NatCo Journal of Virology.

Current Opinion in Virology. December 20, June 16, Nucleic Acids Research. Biological Chemistry Submitted manuscript. Nature Medicine. Bibcode : PNAS A combination of antibody , antigen and nucleic acid tests are used by blood banks in Western countries. The World Health Organization estimated that, as of [update] , inadequate blood screening had resulted in 1 million new HIV infections worldwide.

Tests used for the diagnosis of HIV infection in a particular person require a high degree of both sensitivity and specificity. If antibodies are detected by an initial test based on the ELISA method, then a second test using the Western blot procedure determines the size of the antigens in the test kit binding to the antibodies. The combination of these two methods is highly accurate see below. Considerable controversy exists over the ethical obligations of health care providers to inform the sexual partners of individuals infected with HIV that they are at risk of contracting the virus.

More state funded testing sites are now using confidential forms of testing. This allows for monitoring of infected individuals easily, compared to anonymous testing that has a number attached to the positive test results.

Controversy exists over privacy issues. Rapid HIV tests are most often used, so results are available for the client between 15 and 30 minutes. Furthermore, when an HIV positive result is communicated, the HTC provider can offer appropriate linkages for prevention, care, and treatment.

Testing that has only a number attached to the specimen that will be delivered for testing. Items that are confirmed positive will not have the HIV infected individual's name attached to the specimen. Sites that offer this service advertise this testing option. In the United States, one emerging standard of care is to screen all patients for HIV in all health care settings.

An evaluation of the law's impact found that it increased testing significantly throughout the state. HIV antibody tests are specifically designed for routine diagnostic testing of adults; these tests are inexpensive and extremely accurate. Antibody tests may give false negative no antibodies were detected despite the presence of HIV results during the window period , an interval of three weeks to six months between the time of HIV infection and the production of measurable antibodies to HIV seroconversion.

Most people develop detectable antibodies approximately 30 days after infection, although some seroconvert later. Antiretroviral therapy during the window period can delay the formation of antibodies and extend the window period beyond 12 months. Those patients must take ELISA tests at various intervals after the usual day course of treatment, sometimes extending outside of the conservative window period of 6 months. Antibody tests may also yield false negative results in patients with X-linked agammaglobulinemia ; other diagnostic tests should be used in such patients.

Three instances of delayed HIV seroconversion occurring in health-care workers have been reported; [15] in these instances, the health-care workers [16] tested negative for HIV antibodies greater than 6 months postexposure but were seropositive within 12 months after the exposure. Two of the delayed seroconversions were associated with simultaneous exposure to hepatitis C virus HCV. In one case, co-infection was associated with a rapidly fatal HCV disease course; however, it is not known whether HCV directly influences the risk for or course of HIV infection or is a marker for other exposure-related factors.

It has a high sensitivity. The plate is then washed to remove all other components of the serum. A specially prepared " secondary antibody " — an antibody that binds to human antibodies — is then applied to the plate, followed by another wash.

This secondary antibody is chemically linked in advance to an enzyme. Thus the plate will contain enzyme in proportion to the amount of secondary antibody bound to the plate. A substrate for the enzyme is applied, and catalysis by the enzyme leads to a change in color or fluorescence. ELISA results are reported as a number; the most controversial aspect of this test is determining the "cut-off" point between a positive and negative result.

It is compatible to any smartphone or computer without additional support or battery power, and takes some fifteen minutes to analyse a drop of blood. In subsequent steps, the binding of serum antibodies to specific HIV proteins is visualized. Specifically, cells that may be HIV-infected are opened and the proteins within are placed into a slab of gel, to which an electric current is applied.

Different proteins will move with different speeds in this field, depending on their size, while their electrical charge is leveled by a surfactant called sodium lauryl sulfate. Some commercially prepared Western blot test kits contain the HIV proteins already on a cellulose acetate strip. Once the proteins are well-separated, they are transferred to a membrane and the procedure continues similar to an ELISA: the person's diluted serum is applied to the membrane and antibodies in the serum may attach to some of the HIV proteins.

Antibodies that do not attach are washed away, and enzyme-linked antibodies with the capability to attach to the person's antibodies determine to which HIV proteins the person has antibodies. There are no universal criteria for interpreting the western blot test: The number of viral bands that must be present may vary. If no viral bands are detected, the result is negative. The three-gene-product approach to western blot interpretation has not been adopted for public health or clinical practice.

Tests in which less than the required number of viral bands are detected are reported as indeterminate: a person who has an indeterminate result should be retested, as later tests may be more conclusive. Almost all HIV-infected persons with indeterminate western blot results will develop a positive result when tested in one month; persistently indeterminate results over a period of six months suggests the results are not due to HIV infection. In a generally healthy low-risk population, indeterminate results on western blot occur on the order of 1 in 5, patients.

Rapid antibody tests are qualitative immunoassays intended for use in point-of-care testing to aid in the diagnosis of HIV infection. These tests should be used in conjunction with the clinical status, history, and risk factors of the person being tested.

The positive predictive value of Rapid Antibody Tests in low-risk populations has not been evaluated. These tests should be used in appropriate multi-test algorithms designed for statistical validation of rapid HIV test results. It may take several months after HIV infection for the antibody response to reach detectable levels, during which time rapid testing for antibodies to HIV will not be indicative of true infection status.

For most people, HIV antibodies reach a detectable level after two to six weeks. Although these tests have high specificity, false positives do occur. Any positive test result should be confirmed by a lab using the western blot. This is why a confirmatory western blot is always used before reporting a "positive" HIV test result. False positives may be associated with medical conditions such as recent acute illnesses and allergies.

A rash of false positive tests in the fall of was initially blamed on the influenza vaccines used during that flu season, but further investigation traced the cross-reactivity to several relatively non-specific test kits. When the ELISA test is combined with Western Blot, the rate of false positives is extremely low, and diagnostic accuracy is very high see below. Modern HIV testing is highly accurate. Preventive Services Task Force. A large study of HIV testing in U.

The specificity rate given here for the inexpensive enzyme immunoassay screening tests indicates that, in 1, HIV test results of healthy individuals, about 15 of these results will be a false positive. Confirming the test result i. The sensitivity rating, likewise, indicates that, in 1, test results of HIV infected people, 3 will actually be a false negative result. However, based upon the HIV prevalence rates at most testing centers within the United States, the negative predictive value of these tests is extremely high, meaning that a negative test result will be correct more than 9, times in 10, The very high negative predictive value of these tests is why the CDC recommends that a negative test result be considered conclusive evidence that an individual does not have HIV.

Of course, the actual numbers vary depending on the testing population. Generally the prior probability is estimated using the prevalence of a disease within a population or at a given testing location. The positive predictive value and negative predictive value of all tests, including HIV tests, take into account the prior probability of having a disease along with the accuracy of the testing method to determine a new degree of belief that an individual has or does not have a disease also known as the posterior probability.

The chance that a positive test accurately indicates an HIV infection increases as the prevalence or rate of HIV infection increases in the population. Conversely, the negative predictive value will decrease as the HIV prevalence rises. Thus a positive test in a high-risk population, such as people who frequently engage in unprotected anal intercourse with unknown partners, is more likely to correctly represent HIV infection than a positive test in a very low-risk population, such as unpaid blood donors.

Many studies have confirmed the accuracy of current methods of HIV testing in the United States , reporting false-positive rates of 0. The p24 antigen test detects the presence of the p24 protein of HIV also known as CA , the capsid protein of the virus.

Monoclonal antibodies specific to the p24 protein are mixed with the person's blood. Any p24 protein in the person's blood will stick to the monoclonal antibody and an enzyme-linked antibody to the monoclonal antibodies to p24 causes a color change if p24 was present in the sample. In blood donation screening, this test is no longer used routinely in the US [32] or the EU [33] since the objective was to reduce the risk of false negatives in the window period.

Nucleic acid testing NAT is more effective for this purpose, and p24 antigen testing is no longer indicated if a NAT test is performed. In general diagnostics, p24 antigen tests are used for early detection of HIV, as p24 antigen rises soon after infection relative to antibodies, and the test is often used in combination with an antibody test to effectively cover a longer portion of the window period.

It is less useful as a standalone test, as it has low sensitivity and only works during the early time period after infection. The presence of p24 antigen diminishes as the body increases production of antibodies to the p24 protein, making p24 more difficult to detect later.

A combination, or 4th generation assay, is designed to detect both the p24 antigen and HIV antibodies in a single test.

Combination tests can detect HIV as early as 2—6 weeks after infection, [34] and are recommended in laboratory testing. The polymerase chain reaction PCR process is then applied, using two primers unique to the virus's genome. After PCR amplification is complete, the resulting DNA products are hybridized to specific oligonucleotides bound to the vessel wall, and are then made visible with a probe bound to an enzyme.

The amount of virus in the sample can be quantified with sufficient accuracy to detect threefold changes. Special oligonucleotides that bind to viral RNA and to certain oligonucleotides bound to the wall of the vessel are added. In this way, viral RNA is fastened to the wall. Then new oligonucleotides that bind at several locations to this RNA are added, and other oligonucelotides that bind at several locations to those oligonucleotides.

HIV AIDS - Health Encyclopedia - University of Rochester Medical Center

The current definition of AIDS includes:. HIV-infected people who have been diagnosed with 1 or more health conditions that affect people with advanced HIV disease.

These conditions include certain cancers. According to the CDC, about 1. Many more people are living with HIV infection outside the U. The HIV epidemic is still not well-controlled in some parts of the world.

HIV destroys or hurts immune system cells. It weakens the body's ability to fight infections and certain cancers. HIV is most often spread by having sex with an infected partner whose HIV is not diagnosed or not under control. Another way to spread HIV is by having contact with infected blood from contaminated needles, syringes, or other drug equipment.

But it can be controlled. And much of the damage from the infection can be reversed or prevented. But if HIV is left untreated, serious infections and cancers occur because of the weakened immune system. And the virus can be passed on to others. The risk of becoming infected with HIV depends on the type of activity. HIV is spread through blood, pre-seminal fluid and semen, fluids from the vagina and rectum, and breastmilk.

So these types of behaviors put people at risk of getting or becoming infected with HIV:. Having vaginal or anal sex with a person infected with HIV whose virus is not under control. Sexual contact is the most common way the virus is spread.

The virus enters the body through the lining of the vagina, penis, rectum, or mouth during sexual activity. Unprotected anal sex has the highest risk of transmission. Having multiple sex partners. This includes any partners whose HIV status is not known. It also includes a partner who has HIV, but whose virus is not under control. Or a partner who has poor or uncertain control of their HIV. Having high-risk sexual partners. This includes a partner who is a sex worker, or someone who has sex with many other people.

Or someone who uses IV drugs. Sharing needles, syringes, or other drug equipment with someone with HIV whose virus is not under control. Using alcohol and other drugs.

They make it more likely that people will do risky things such as having unprotected sex. Having a sexually transmitted disease STD. STDs can cause changes in the tissue of the vagina or penis. Having an accidental stick from a needle or medical device contaminated with HIV. But it is rare for a person with HIV to spread the virus to a healthcare worker this way. Or for a healthcare worker to spread the virus to a patient.

Having a blood transfusion. HIV may also be spread through contact with infected blood. But the risk of getting HIV from blood transfusions is very low. This is because blood is screened for signs of HIV infection in the U.

Risks to an unborn child. A mother infected with HIV can give her baby the virus before or during birth. This is especially true if her HIV is not well controlled. She can also pass the virus by breastfeeding. Pregnant women should always be tested and treated for HIV. Many people develop a flu-like illness within 2 to 6 weeks after exposure to the HIV virus. In addition, the symptoms that do appear often go away within a week to a month.

And they are often mistaken for those of another viral infection. These symptoms may include:. Constant or severe symptoms may not show up for 10 years or more after HIV first enters the body in adults.

In children born with an HIV infection, it may take 2 years for symptoms to appear. This period of no symptoms can be different for each person. But during this time, HIV is actively infecting and killing immune system cells. These cells are key infection fighters in the immune system.

As the immune system weakens, complications or symptoms begin to appear. Symptoms may include:. One or more infections opportunistic infections linked to having a weakened immune system. These include tuberculosis and certain types of pneumonia. Some people develop frequent and severe herpes infections. These cause mouth, genital, or anal sores, or a painful nerve disease known as shingles. Children may have delayed development or slowed growth failure to thrive. Some people may have sudden and severe drops in these cell counts.

The symptoms of HIV infection may look like other health conditions. Always talk with your healthcare provider for a diagnosis. Quick diagnostic tests are available and early diagnosis is important. Early HIV infection often causes no symptoms.

It must be found by testing a person's blood for disease-fighting proteins antibodies against HIV. Or the virus itself can be detected. Tests used to find antigen-antibody are a preferred method of testing. Antigens are foreign substances virus. Antibodies are made by the body to fight the antigens.

Testing for antibodies and the virus may not be positive until 2 to 12 weeks after infection. People exposed to HIV should be tested for HIV infection as soon as they think they may have been exposed to the virus. In some cases a person may have been recently exposed or possibly exposed to HIV and early testing is negative. Then repeat testing in 2 to 12 weeks will often be advised.

As with many other conditions, finding HIV early offers more chances for successful treatment. Antiviral medicines for HIV can stop the virus from further harming the body.

This allows some or all of the damage to be healed. People can then often live a normal life span and have a normal sex life and family life.

There is currently no cure for HIV infection. But people who takes the medicines and stay on them may be able to keep the virus completely under control. A lot of research is being done to find a vaccine that might either prevent HIV infection or help the body to better control HIV infection. Currently, no vaccine has been shown to be effective enough to be used. HIV is most often spread by having sex with an infected partner. It can also spread by having contact with infected blood from contaminated needles, syringes, or other drug equipment.

Many people have a flu-like illness within 2 to 6 weeks after exposure to the HIV virus. Bring someone with you to help you ask questions and remember what your provider tells you. At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests.

Also write down any new instructions your provider gives you. Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

Know what to expect if you do not take the medicine or have the test or procedure. If you have a follow-up appointment, write down the date, time, and purpose for that visit. Search Encyclopedia. So these types of behaviors put people at risk of getting or becoming infected with HIV: Having vaginal or anal sex with a person infected with HIV whose virus is not under control. Other factors that can put people at risk include: Using alcohol and other drugs. These symptoms may include: Fever Headache General feeling of discomfort malaise Enlarged lymph nodes Rash Constant or severe symptoms may not show up for 10 years or more after HIV first enters the body in adults.

Symptoms may include: Lymph nodes that stay enlarged for more than 3 months Lack of energy Weight loss Frequent fevers and sweats Constant or frequent yeast infections oral or vaginal Constant skin rashes or flaky skin Diarrhea that keeps coming back Short-term memory loss One or more infections opportunistic infections linked to having a weakened immune system.

But it can be controlled with antiviral medicines.

Medical encyclopedia hiv