HIV/AIDS

English: A view of the Centers for Disease Control and Prevention

Human immunodeficiency virus infection / acquired immunodeficiency syndrome (HIV/AIDS) is a disease of the human immune system caused by infection with human immunodeficiency virus (HIV).^[1] During the initial infection, a person may experience a brief period of influenza-like illness. This is typically followed by a prolonged period without symptoms. As the illness progresses, it interferes more and more with the immune system, making the person much more likely to get infections, including opportunistic infections and tumors that do not usually affect people who have working immune systems.

 

HIV is transmitted primarily via unprotected sexual intercourse (including anal and even oral sex), contaminated blood transfusions, hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding.^[2] Some bodily fluids, such as saliva and tears, do not transmit HIV.^[3] Prevention of HIV infection, primarily through safe sex and needle-exchange programs, is a key strategy to control the spread of the disease. There is no cure or vaccine; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. While antiretroviral treatment reduces the risk of death and complications from the disease, these medications are expensive and may be associated with side effects.

 

Genetic research indicates that HIV originated in west-central Africa during the early twentieth century.^[4] AIDS was first recognized by the Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.^[5] Since its discovery, AIDS has caused nearly 30 million deaths (as of 2009).^[6] As of 2010, approximately 34 million people are living with HIV globally.^[7] AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading.^[8]

HIV/AIDS has had a great impact on society, both as an illness and as a source of discrimination. The disease also has significant economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has also become subject to many controversies involving religion.

 

The initial period following the contraction of HIV is called acute HIV, primary HIV or acute retroviral syndrome.^[9][11] Many individuals develop an influenza-like illness or a mononucleosis-like illness 2–4 weeks post exposure while others have no significant symptoms.^[12][13] Symptoms occur in 40–90% of cases and most commonly include fever, large tender lymph nodes, throat inflammation, a rash, headache, and/or sores of the mouth and genitals.^[11][13] The rash, which occurs in 20–50% of cases, presents itself on the trunk and is maculopapular, classically.^[14] Some people also develop opportunistic infections at this stage.^[11] Gastrointestinal symptoms such as nausea, vomiting or diarrhea may occur, as may neurological symptoms of peripheral neuropathy or Guillain-Barre syndrome.^[13] The duration of the symptoms varies, but is usually one or two weeks.^[13]

 

Due 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 patients presenting an unexplained fever who may have risk factors for the infection.^[13]

Clinical latency

The initial symptoms are followed by a stage called clinical latency, asymptomatic HIV, or chronic HIV.^[10] Without treatment, this second stage of the natural history of HIV infection can last from about three years^[15] to over 20 years^[16] (on average, about eight years).^[17] While typically there are few or no symptoms at first, near the end of this stage many people experience fever, weight loss, gastrointestinal problems and muscle pains.^[10] Between 50 and 70% of people also develop persistent generalized lymphadenopathy, characterized by unexplained, non-painful enlargement of more than one group of lymph nodes (other than in the groin) for over three to six months.^[9]

 

Although most HIV-1 infected individuals have a detectable viral load and in the absence of treatment will eventually progress to AIDS, a small proportion (about 5%) retain high levels of CD4⁺ T cells (T helper cells) without antiretroviral therapy for more than 5 years.^[13][18] These individuals are classified as HIV controllers or long-term nonprogressors (LTNP).^[18] Another group is those who also maintain a low or undetectable viral load without anti-retroviral treatment who are known as "elite controllers" or "elite suppressors". They represent approximately 1 in 300 infected persons.^[19]

 

AIDS was first clinically observed in 1981 in the United States.^[22] The initial cases were a cluster of injecting drug users and homosexual men with no known cause of impaired immunity who showed symptoms of Pneumocystis carinii pneumonia (PCP), a rare opportunistic infection that was known to occur in people with very compromised immune systems.^[167] Soon thereafter, an unexpected number of gay men developed a previously rare skin cancer called Kaposi's sarcoma (KS).^[168][169] Many more cases of PCP and KS emerged, alerting U.S. Centers for Disease Control and Prevention (CDC) and a CDC task force was formed to monitor the outbreak

 

In the early days, 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.^[171][172] They also used Kaposi's Sarcoma and Opportunistic Infections, the name by which a task force had been set up in 1981.^[173] At one point, the CDC coined the phrase "the 4H disease", since the syndrome seemed to affect Haitians, homosexuals, hemophiliacs, and heroin users.^[174] In the general press, the term "GRID", which stood for gay-related immune deficiency, had been coined.^[175] However, after determining that AIDS was not isolated to the gay community,^[173] it was realized that the term GRID was misleading and the term AIDS was introduced at a meeting in July 1982.^[176] By September 1982 the CDC started referring to the disease as AIDS.^[177]

 

In 1983, two separate research groups led by Robert Gallo and Luc Montagnier independently declared that a novel retrovirus may have been infecting AIDS patients, and published their findings in the same issue of the journal Science.^[178][179] Gallo claimed that a virus his group had isolated from an AIDS patient was strikingly similar in shape to other human T-lymphotropic viruses (HTLVs) his group had been the first to isolate. Gallo's group called their newly isolated virus HTLV-III. 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 characteristic symptoms of AIDS. 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).^[170] As these two viruses turned out to be the same, in 1986, LAV and HTLV-III were renamed HIV.^[180]

Origins

Both HIV-1 and HIV-2 are believed to have originated in non-human primates in West-central Africa and were transferred to humans in the early 20th century.^[4] HIV-1 appears to have originated in southern Cameroon through the evolution of SIV(cpz), a simian immunodeficiency virus (SIV) that infects wild chimpanzees (HIV-1 descends from the SIVcpz endemic in the chimpanzee subspecies Pan troglodytes troglodytes).^[181][182] The closest relative of HIV-2 is SIV(smm), a virus of the sooty mangabey (Cercocebus atys atys), an Old World monkey living in coastal West Africa (from southern Senegal to western Côte d'Ivoire).^[62] New World monkeys such as the owl monkey are resistant to HIV-1 infection, possibly because of a genomic fusion of two viral resistance genes.^[183] 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 ODenial, conspiracies, and misconceptions

Main articles: AIDS denialism and Misconceptions about HIV/AIDS

A small group of individuals continue to dispute the connection between HIV and AIDS,^[217] the existence of HIV itself, or the validity of HIV testing and treatment methods.^[218][219] These claims, known as AIDS denialism, have been examined and rejected by the scientific community.^[220] However, they have had a significant political impact, particularly in South Africa, where the government's official embrace of AIDS denialism (1999–2005) was responsible for its ineffective response to that country's AIDS epidemic, and has been blamed for hundreds of thousands of avoidable deaths and HIV infections.^{[221][222][223]} Operation INFEKTION was a worldwide Soviet active measures operation to spread information that the United States had created HIV/AIDS. Surveys show that a significant number of people believed – and continue to believe – in such claims.^[224]

There are many misconceptions about HIV and AIDS. Three of the most common are that AIDS can spread through casual contact, that sexual intercourse with a virgin will cure AIDS, and that HIV can infect only homosexual men and drug users. Other misconceptions are that any act of anal intercourse between two uninfected gay men can lead to HIV infection, and that open discussion of homosexuality and HIV in schools will lead to increased rates of homosexuality and AIDS.^[225][226]

Research

Main article: HIV/AIDS research

HIV/AIDS research includes all medical research which attempts to prevent, treat, or cure HIV/AIDS along with fundamental research about the nature of HIV as an infectious agent and AIDS as the disease caused by HIV.

HIV/AIDS research includes following the usual advice given by doctors in responding to HIV. The most universally recommended method for the prevention of HIV/AIDS is to avoid blood-to-blood contact between people and to otherwise practice safe sex. The most recommended method for treating HIV is for HIV-positive people to receive attention from a doctor who would coordinate the patient's management of HIV/AIDS. There is no cure for HIV/AIDS.

Many governments and research institutions participate in HIV/AIDS research. This research includes behavioral health interventions such as sex education, and drug development, such as research into microbicides for sexually transmitted diseases, HIV vaccines, and antiretroviral drugs. Other medical research areas include the topics of pre-exposure prophylaxis, post-exposure prophylaxis, and Circumcision and HIV..^[184].^[170]