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The Red Ribbon symbol is used internationally to represent the fight against AIDS.

AIDS (Acquired Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome, rarely written Aids) is a disease characterized by the destruction of the human immune system. It stands today as a global epidemic, that originated in sub-Saharan Africa during the twentieth century. Although there are treatments to hinder the progress of AIDS, there is yet no known cure or vaccine.

AIDS is the result of an infection with HIV, the Human Immunodeficiency Virus. HIV is a lentivirus, a genus of retrovirus that is characterized by long latency periods [1] ( and lipid-coated outer shells [2] ( HIV causes destruction of the immune system's T cells, weakening it and rendering the body unable to fight off infections and cancer. A person with HIV who has a CD4+ T cell count below 200/mm3 or one of a list of AIDS defining illnesses, is diagnosed with AIDS.

Two species of HIV infect humans: HIV-1 and HIV-2. HIV-1 is more virulent and more easily transmitted. HIV-1 is the source of the majority of HIV infections thoughout the world, while HIV-2 is less easily transmitted and is largely confined to West Africa. [3] ( The World Health Organization estimated that between 2.8 and 3.5 million people with AIDS died in 2004. An estimated 60% of people with AIDS live in sub-Saharan Africa, where medical procedures including blood transfusions remain sources of new AIDS cases [4] (



The CDC defines the beginning of AIDS as when a person with HIV infection has either a CD4 cell count below 200 or one of several conditions associated with a weakend immune response.[5] ( The term AIDS (acquired immunodeficiency syndrome) was proposed on July 27, 1982 at a meeting in Washington. [6] (

A person who has been living with HIV for 7 to 12 years, has a stable CD4 cell count above 600, no HIV-related diseases, and no antiretroviral therapy is called a long-term nonprogressor. [7] ( As many as 5% of all HIV infected people may possess a natural immunity that prevents them from developing AIDS. [8] (


Both species of the virus (HIV-1 and HIV-2) originated in West-Central Africa and jumped species from primates to humans. HIV-1 has evolved from a Simian Immunodeficiency Virus (SIVcpz) found in the chimpanzee subspecies, Pan troglodyte troglodyte.[9] ( HIV-2 crossed species from a different strain of SIV, this one found in sooty mangabeys (an Old World monkey) of Guinea-Bissau.[10] (

The earliest documented HIV-1 infection dates from 1959, and was discovered in the preserved blood sample of a man from Kinshasa in the Democratic Republic of the Congo. Sequencing of the virus from that sample indicates that HIV-1 was probably introduced into the human population in the early to mid-20th century.[11] ( Other early samples include one for an American male-died in 1969, and one for a Norwegian sailor of 1976. The earliest journaled death more lenient to the West- in due to AIDS, is attributed to Dr. Grethe Rask who was a Danish surgeon in the early 1970s of Congo. Some believe the AIDS epidemic can be traced further back than those dates.

The official date for the beginning of the AIDS pandemic is marked as June 5, 1981, when the US Center for Disease Control and Prevention reported in a newsletter that unusual clusters of Kaposi's sarcoma were discovered in gay men in New York and San Francisco in the late 1970s. More KS clusters were discovered among these otherwise healthy men in other cities throughout the country, and a subsequent investigation of these infections revealed that the victims had other opportunistic diseases as well. Many died within a few months of diagnosis despite receiving the best treatments at the time, leading to speculation that they had an immune disorder hampering their ability to fight the multiple infections.

The AIDS report of opportunistic infections for gay male intravenous drug users from the 1980s was initially termed 'GRID' (Gay Related Immune Deficiency). However, similar opportunistic infections were reported in people in other categories. By the end of 1982, more AIDS cases emerged around the world, especially blood transfusion recipients, intravenous drug users, and immigrants from certain countries such as Haiti. The disorder was officially renamed AIDS at the end of 1983.

Some past studies of AIDS in Africa have used a very loose definition that results in the overdiagnosis of AIDS, even when HIV is not present, because this definition avoids expensive tests. This complicates epidemiological comparisons. The controversial OPV AIDS hypothesis raises speculation that the origin of AIDS is due to the oral polio vaccination program that took place in the late 1950s of Africa.

Transmission and infection

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Diagram of the HIV virus

In January 2005, Anthony S. Fauci, M.D., director of NIAID said, "Individual risk of acquiring HIV and experiencing rapid disease progression is not uniform within populations". NIH press release (

Patterns of HIV transmission vary in different parts of the world. In Africa, which accounts for an estimated 60% of new HIV infections worldwide, controversy rages over the respective contribution of medical procedures, heterosexual sex and the bush meat trade. In the United States, sex between men (48% with 60% of these limited to African-American men, more than four times more likely to be infected than their Caucasian counterparts at 15%), any sex between African-Americans (52%) and injecting drug (34%) use remain prominent sources of new HIV infections, with the fastest growing group being African-American women (72% of cases in women). Studies have shown that antiretroviral drugs, cesarean delivery and formula feeding reduce the chance of transmisison of HIV from mother to child [12] (

A newly infected person may be highly infectious as it is during this time that the HIV viral load in the blood plasma is highest. At this stage, the virus is still multiplying rapidly, unchecked, because the body has not yet started to produce antibodies to the virus.

During the asymptomatic stage, billions of HIV particles are produced every day accompanied by a decline, at variable rates, in the number of CD4+ T cells. The virus is not only present in the blood, but also throughout the body, particularly in the lymph nodes, brain, and genital secretions. During this stage, the body's immune system is actively trying to fight off the HIV infection but, for the vast majority of infected people who are not receiving treatment, the immune response is insufficient as the virus directly attacks cells of the immune system and mutates rapidly.

Alternative theories

Main article: AIDS reappraisal

While the majority scientific opinion is that HIV causes AIDS, a number of scientists and activists question the connection between HIV and AIDS, or the existence of HIV, or the validity of current testing methods.

A growing number of scientists believe that HIV induces something similar to an autoimmune disease, in which the body attacks its own cells, rather than being directly pathogenic.[13] (


There is currently no cure or vaccine for HIV or AIDS. Current optimal treatment options consist of combinations ("cocktails") of two or more types of anti-retroviral agents such as two nucleoside analogue reverse transcriptase inhibitors (NRTIs), and a protease inhibitor or a non nucleoside reverse transcriptase inhibitor (NNRTI). [14] ( Newer treatments such as anti-retroviral treatments have played a part in delaying the onset of AIDS, on reducing the symptoms, and extending patients' life spans. Over the past decade the success of these treatments in prolonging, and improving the quality of life for people with AIDS has improved dramatically. (Wood et al 2003), (Egger et al 2002).

There are several concerns about anti-retroviral regimens. The drugs can have serious side effects. Regimens can be complicated, requiring patients to take several pills at various times during the day. If patients miss doses, drug resistance can develop (Dybul et al 2002).

In recent years the term HAART (highly-active anti-retroviral therapy) has been commonly used. Anti-retroviral drugs are costly, and the majority of the world's infected individuals do not have access to medications and treatments for HIV and AIDS.

The current guidelines for anti-retroviral therapy ( from the World Health Organization recommend that anti-retroviral therapy should start when a patient's CD4 count drops below 200/mm3, or an AIDS defining illness is diagnosed. The HIV/AIDS Bureau (HAB) of the U.S. Health Resources and Services Administration states that anti-retroviral therapy should begin when the CD4 cell count is between 200 and 350/mm3. HAB recommends that doctors should assess the viral load, rapidity in CD4 decline, and patient readiness while deciding when to begin treatment. [15] (

Research to improve current treatments includes decreasing side effects of current drugs, simplifying drug regimens to improve adherence, and determining the best sequence of regimens to manage drug resistance.

Alternative medicine

Ever since AIDS entered the public consciousness, various forms of alternative medicine have been used to treat its symptoms. In the first decade of the epidemic when no useful conventional treatment was available, a large number of people with AIDS experimented with alternative therapies (massage, herbal and flower remedies and acupuncture). Interest in these therapies has declined over the past decade as conventional treatments have improved. People with AIDS, like people with other illnesses such as cancer, also sometimes use marijuana to treat pain, combat nausea and stimulate appetite.


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CDC 2005

Current strategies to prevent AIDS are directed at the prevention of human-to-human bodily fluid transmissions.

HIV is transmitable through sexual acts involving the exchange of bodily fluids, through blood needle sharing, blood transfusions from infected donors and from mother to infant transmission during birth and breastfeeding. UNAIDS transmison (

Safe sex

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Stop AIDS Project marchers at San Francisco Pride 2004.

HIV transmission via sexual activity has been recorded for male to male, male to female, female to female and female to male contacts. Chances of HIV transmission from is significantly higher if a partner is infected with a different STD ( because of presence of ulcers and lesions in genital areas ), during the first year of development of AIDS in the infected partner, or during anal sex.

Health organizations endorse the "ABC Approach" to lower the risk of AIDS infection via sexual acts:

  • Abstinence or delay of sexual activity
  • Be faithful and reduce partner numbers
  • Condom use

"Health experts around the world urge males to use condoms to protect themselves from HIV and a host of sexually transmitted infections." [16] ( Although condoms are not completely guaranteed to prevent pregnancy or sexually transmitted disease(STD)), it has been repeatedly verified that the risk of HIV transmission during intercourse is significantly decreased with the proper use of latex condoms.

Anal sex, because of the risk of anal tissue tearing and thus blood contact, is the riskiest form of sexual activity for transmitting the virus.

Chances of HIV transmission from infected male to female vaginal sex are low - under normal conditions, only about 10 in 10,000 results in infection according to the CDC estimates in the United States. Transmission of virus from females to males is only about half as likely, 5 in 10,000, though still possible. Note that these CDC estimates are averages, and actual odds of transmission of HIV via a single sexual act can be affected by other factors, such as the viral load of the infected partner or the presence of abrasions or sores on the genitals of either of the sexual partners.

The risk factor of oral sex HIV transmission is extremely low. The potential mode of transmission would be via the mouth or throat. If small tears or soars exist, infection could be possible if they received the semen or vaginal fluids. Using a condom or dental dam could prevent infected fluids from touching these open wounds. The fact is, oral sex carries far less of a risk HIV transmission than does genital and anal sex, and "has not been strongly associated with HIV transmission..." (Fan et al. 121).

Intravenous drug use

HIV can be transmitted via the sharing of needles by users of intravenous drugs, and cumulative data from 1981 to 2001 has shown that 31% of people with AIDS in the United States are injection drug users (Fan et. al., 99). All AIDS-prevention organisations advise drug-users not to share needles and to use a new or properly sterilized needle for each injection. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. In the United States and other western countries, clean needles are available free in some cities, at needle exchanges or safe injection sites.

Birthing and Breastmilk

When a mother is infected with HIV she must take caution in order not to spread HIV to her infant. During pregnancy in the third trimester small tears can happen on in the placenta, and with birth both blood and vaginal fluids come into contact with the child. After a baby has been delivered from an infected mother, it have stood a 23% chance of infection. With AZT monotherapy, an anti-retroviral drug, this chance can further be reduced to 8%. (Fan et. al., 117).

The mother can also pass HIV to her baby via breastmilk, which carries a high content of HIV infected cells (Fan et. al., 114). Prevention involves giving the baby a substitute for the mother's breastmilk during rearing.

WHO makes the following recommendations:

  • When replacement feeding is acceptable, feasible, affordable, sustainable and safe, avoiding breastfeeding by HIV-infected mothers is recommended. Otherwise, exclusive breastfeeding is recommended during the first months of life and should be discontinued as soon as possible. [17] (

HIV blood screening

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HIV daughter particles being shed from an infected T cell

Blood tranfusions remain a source of new HIV infections. According to the WHO [18] (, "between 5% and 10% of HIV infections worldwide are transmitted through the transfusion of infected blood and blood products. WHO/UNAIDS estimate that 5.6 million new HIV infections occur annually from such transfusions." In those countries where improved donor selection and antibody tests have been introduced, the risk of transmitting HIV infection to blood transfusion recipients has been effectively eliminated.

Medical procedures

Medical workers who follow universal precautions or body substance isolation such as wearing latex gloves when giving injections and washing the hands frequently can help prevent infection of HIV. The risk of being infected with HIV from a single prick with a needle that has been used on an HIV infected person though is thought to be about 1 in 150 (see table above). Post-exposure prophylaxis with anti-HIV drugs can further reduce that small risk. (Fan et. al., 119)

However, health clinics in some countries are responsible for as much as 30% of HIV transmission worldwide ( There is an urgent need to address medical transmission as a priority in these countries. see HIV transmission in the medical setting (

Vaccine research

There is still no vaccine for HIV, but ongoing research and human trials are currently underway. VRX496, a genetic component to suppress HIV (specifically a form of antisense therapy) carried in a modified lentivirus, entered Phase I clinical trials in 2003—the first use of a lentiviral vector in humans. Gene therapy has also been suggested as a possible approach to preventing or treating HIV infection. Because of slow progress to date in the development of a vaccine, new approaches are being investigated to encourage industry involvement, including prizes, tax breaks, and advance market commitments.

Current status

UNAIDS and the World Health Organization estimated that between 36 and 44 million people around the world were living with HIV in December 2004 [19] ( It was estimated that during 2004, between 4.3 and 6.4 million people were newly infected with HIV and between 2.8 and 3.5 million people with AIDS died. Sub-Saharan Africa remains by far the worst-affected region, with 23.4 million to 28.4 million people living with HIV at the end of 2004. Just under two thirds (64%) of all people living with HIV are in sub-Saharan Africa, as are more than three quarters (76%) of all women living with HIV. [20] (

World region Estimated adult prevalence of HIV infection
(ages 15–49)
Estimated adult and child deaths
during 2004
Sub-Saharan Africa 6.9% to 8.3% 2.1 to 2.6 million
Caribbean 1.5% to 4.1% 24,000 to 61,000
Asia 0.3% to 0.6% 350,000 to 810,000
Eastern Europe and Central Asia 0.5% to 1.2% 39,000 to 87,000
Latin America 0.5% to 0.8% 73,000 to 120,000
Oceania 0.1% to 0.3% fewer than 1,700
Middle East and North Africa: 0.1% to 0.7% 12,000 to 72,000
North America, Western and Central Europe 0.3% to 0.6% 15,000 to 32,000
UNAIDS and the WHO 2004 estimates. The ranges define the boundaries within which the actual numbers lie, based on the best available information. [21] (

More than 23 million people with AIDS have died since since 1981. [22] ( [23] ( [24] ( [25] (

AIDS is a worldwide epidemic. UNAIDS estimated[26] ( that in 2004:

  • 39.4 million people living around the world were HIV carriers;
  • 3.1 million people with AIDS died during 2004 (with a total of 23 million dead since 1981); and
  • 4.9 million were newly infected with HIV.

The majority of AIDS cases can be found in Sub-Saharan Africa, with 68% of adult cases. South & South East Asia are second most affected with 15%. AIDS accounts for the deaths of 500,000 children. These statistical figures have led experts to say this is the deadliest pandemic in human history comparable to the Black Death; other historical comparisons of pandemics include the introduction of smallpox and other Eurasian diseases to the Americas during the 16th century.

In Western countries, the infection rate of HIV has decelerated. This is due in part to the widespread adoption of safe sex practice and educational campaigns in the fight against HIV spreading. Even in some metropolitan areas with large gay communities (notably San Francisco, where the first cases were reported) AIDS cases have fallen to levels not seen since the original outbreak; many attribute this trend to aggressive educational campaigns.

In some cities, however, there are young urban gay men of African descent as well as a good majority of African-American communities where infection rates began to show dangerous signs of rising levels for the 1990s. In Britain the number of people diagnosed with HIV increased 26% for 2000 to 2001. In the United States blacks make up about 47% of the total HIV-positive population, yet also make up more than half of new HIV cases, despite making up only 12% of the population. In addition, if you are a black woman you are 19 times more likely to contract HIV than a white woman [27] ( Experts attribute this to "AIDS fatigue" among younger people who have no memory of the worst phase of the epidemic in the 1980s, as well as "condom fatigue" among those who have grown tired of and disillusioned with the unrelenting safer sex message. This trend is of major concern to public health workers. AIDS continues to be a problem with illegal sex workers and injection drug users. On the other hand, the death rate from AIDS in all Western countries has fallen sharply, as new AIDS therapies have proven to be an effective (if expensive) means of suppressing HIV.

In the United States in particular, a new wave of infection rates among gay men is being blamed on the use of methamphetamine, known as Crystal meth (for full article see Crystal and sex. Research presented at the 12th Annual Retrovirus Conference in Boston in February, 2005 concluded that using Crystal meth or cocaine is the biggest single risk factor for becoming HIV+ among US gay men, contributing 29% of the overall risk of becoming positive and 28% of the overall risk of being the receptive partner in bareback sex[28] ( In addition, several renowned clinical psychologists now cite Crystal as the biggest problem facing gay men today, including Michael Majeski, who reckons meth is the catalyst for at least 80% of seroconversions currently occurring across the United States, and Tony Zimbardi, who calls Crystal the number one cause of HIV transmission, and says that high rates of new HIV infection are not being found among non-Crystal users. In addition, various HIV and STD clinics across the States report anecdotcal evidence that 75% of new HIV seroconversions they deal with are Crystal-related; indeed, in Los Angeles, Crystal is regarded as the main cause of HIV seroconversion among gay men in their late thirties[29] ( The First National Conference on Methamphetamine, HIV and Hepatitis will be held in Salt Lake City in August of 2005.

In developing countries, particularly in Sub-Saharan Africa, poor economic conditions (leading to the use of dirty needles in healthcare clinics) and lack of sex education mean high rate of infection (see AIDS in Africa). In some countries of Africa, 25% or more of the working adult population is HIV-positive; in Botswana alone the figure was 35.8% (1999 estimate World Press Review (, the highest reported prevalence rate in the world. In South Africa, where President Thabo Mbeki denies that HIV is the cause of AIDS, the government does not require that AIDS cases be reported or collect information on the number of South Africans with AIDS. UNAIDS estimates that at the end of 2003 there were 5.3 million people in South Africa living with HIV - 21.5% of the population[30] ( Although HIV prevalence rates are much lower in Nigeria than in other African countries, the size of Nigeria's population meant that by the end of 2003, there were an estimated 3.6 million people living with HIV[31] ( On the other hand, Uganda, Zambia, and Senegal have begun interventional and educational measures to decelerate the spread of HIV, and Uganda has succeeded in actually reducing its HIV prevalence rate[32] (

Latin America and the Caribbean had just over 2.2 million infected persons in 2003, with modes of transmission and infection rates varying widely. The infection rates are highest in Central America and the Caribbean, where heterosexual transmission is fairly common. In Mexico, Brazil, Colombia, and Argentina, drug injection and homosexual activity are the main modes of transmission, but there is concern that heterosexual activity may soon become a primary method of spreading the virus. Brazil recently began a comprehensive AIDS prevention and treatment program to keep AIDS in check, including the production of generic versions of anti-retroviral drugs.

AIDS infection rates are also rising steadily in Asia, with over 7.5 million infections by 2003. In July 2003, the estimated number of HIV+ individuals in India was about 4.6 million, roughly 0.9% of the working adult population. In China, the number was estimated at 1 million to 1.5 million, with some estimates going much higher. Both countries have growing epidemics spread by large numbers of urban sex workers (a technical term for prostitute) and intravenous drug use. China also suffers from an epidemic in some of its rural areas, where large numbers of farmers, especially in Henan province, participated in sloppy procedures for blood transfusions; estimates of those infected are in the tens of thousands. AIDS seems to be under control in Thailand and Cambodia, but new infections occur in those nations at a steady rate.

There is also growing concern about a rapidly growing epidemic in Eastern Europe and Central Asia, where an estimated 1.7 million people were infected by January 2004. The rate of HIV infections rose rapidly from the mid-1990s, due to social and economic collapse, increased levels of intravenous drug use and increased numbers of prostitutes. By 2004 the number of reported cases in Russia was over 257,000, according to the World Health Organization, up from 15,000 in 1995 and 190,000 in 2002; some estimates claim the real number is up to five times higher, over 1 million. There are predictions that the infection rate in Russia will continue to rise quickly, since education there about AIDS is almost non-existent. Ukraine and Estonia also had growing numbers of infected people, with estimates of 500,000 and 3,700 respectively in 2004.

Other HIV/AIDS related articles in Wikipedia
HIV test | Antiretroviral drug | HIV vaccine
AIDS in Africa | AIDS in Latin America | AIDS in the United States
Treatment Action Campaign | XV International AIDS Conference, 2004 | International AIDS Society
World AIDS Day | List of AIDS-related topics |Timeline of AIDS
AIDS myths and urban legends | AIDS conspiracy theories | OPV AIDS hypothesis
Scientific Reappraisal of HIV-AIDS Hypothesis | Duesberg hypothesis
NAMES Project AIDS Memorial Quilt | List of HIV-positive individuals


  • Template:Book reference
  • Wood E, Hogg RS, Yip B, Harrigan PR, O'Shaughnessy MV, Montaner JS. Is there a baseline CD4 cell count that precludes a survival response to modern antiretroviral therapy? AIDS 2003;17:711-20. PMID 12646794.
  • Egger ME, May MT, Chene G, Phillips AN, Ledergerber B, Dabis F, Costagliola D, D'Arminio Monforte A, et al. Prognosis of HIV-infected patients starting highly active antiretroviral therapy: a collaborative analysis of prospective studies. Lancet 2002;360:119-129. PMID 12126821.
  • Dybul M, Fauci AS, Bartlett JG, et al; Panel on Clinical Practices for Treatment of HIV. Guidelines for using antiretroviral agents among HIV-infected adults and adolescents. Ann Intern Med 2002;137:381-433. PMID 12617573.

External links

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