AIDS
The factual accuracy of this article is disputed: see talk:AIDS
AIDS stands for Acquired Immuno-deficiency Syndrome or Acquired Immune Deficiency Syndrome. The name came into common usage in 1981, and refers to a syndrome (group of symptoms) now known to arise from the progressive destruction of the body's immune system. This destruction is caused by infection with the Human Immunodeficiency Virus (HIV), a virus transmitted by bodily fluids such as blood, semen and vaginal secretions.
AIDS is currently considered incurable, but is generally treated as a long-term illness.
History and Early Years of the Epidemic
The era of AIDS officially began in July 1981, when the CDC (US Center for Disease Control) issued a press release describing a clustering of cases of Kaposi's sarcoma, a relatively unusual skin cancer, and Pneumocystis carinii pneumonia in Los Angeles, New York City, and San Francisco.
While Kaposi's sarcoma and pneumocystis carinii were not unknown to physicians, the tight clustering of cases was considered highly unusual. Most patients identified were sexually active homosexual men, many of whom were also discovered to be suffering from other chronic diseases later identified as opportunistic infections. Blood tests revealed that many of the patients were also lacking in adequate numbers of CD4+ T cells. Many of the patients died within a few months.
Since most of the original sufferers were gay men, the then-unknown syndrome was often referred to as GRID (Gay-Related Immune Deficiency), or colloquially as The Plague, but as infected populations grew and shifted, beginning to include Haitian immigrants, intravenous drug users, blood transfusions recipients, and heterosexual women, the disease was officially named AIDS in 1982.
Early Theories of Origin and Transmission
In the early years of AIDS, the exact origin of the virus was unkown, as it still is. A common theory, which even became the subject of an article in Rolling Stone Magazine, held that HIV came from SIV, a virus that causes AIDS-like symptoms in primates, and that this virus was transmitted to human populations in Africa during the course of controversial polio vaccine experiements on African villagers (this theory has since been disproven). It was also commonly believed that the spread of AIDS to the western world was attributable to the sexual behaviour of a single man, Patient Zero, a flight attendant who was said to have had sex with over 1000 men in various countries, and this became the subject of a movie. This theory, too, has been disproven.
Sufferers of AIDS in the early days were frequently ostracized by their communities, friends, and even families. Ryan White, for example, was a young American boy who contracted AIDS through a blood transfusion, and because of protests by the parents of other children was forced to withdraw from school. Sufferes were isolated; people were afraid to be close to them as many mistakenly believed AIDS could be transmitted by casual contact such as holding hands, kissing, hugging, or sharing cups, dishes or eating utensils.
Gay men were frequently blamed for the advent and spread of AIDS in the west. Some claimed that AIDS was a punishment from God for homosexuality (this belief, unfortunately, is still espoused by some). Others claimed that the "depraved lifestyles" of gay men were responsible. It is true that in the early years AIDS spread quickly through gay communities and that a majority of early sufferers were gay men, but this is primarily due to the fact that same-sex sexual activity required no birth control, and thus homosexuals were not using condoms, now known to be an effective barrier against AIDS.
Current Theories of Origin and Transmission
Origin
HIV is closely related to viruses causing AIDS-like diseases in many primates, and is generally thought to have been transferred from animals to humans at some time during the early 20th century, though some evidence suggests it may have been transferred earlier in several isolated cases. The exact animal source, time, and location of the transfer (or indeed, how many transfers there were) is not currently known. A virus virtually identical to human HIV (known as Simian Immunodeficiency Virus, or SIV) has been found in chimpanzees, but it is not known for certain whether the transmission was from chimpanzees to humans, or whether both chimpanzees and humans were infected by a third source.Studies suggest that the virus spread initially in West Africa, but it is possible that there were several separate "initial sources", including South America. The earliest human fluid sample known to contain HIV was taken in 1959 in what is now the Democratic Republic of the Congo. Other early samples include one from an Ameican male who died in 1969, and a Norwegian sailor in 1976.
It is believed that the virus was spread via sexual activity, possibly including with prostitutes, in Africa's rapidly growing urban areas. As unwittingly infected people traveled the virus spread from one city to another, and air travelers carried the virus to other continents.
Transmission
Currently the most common ways to contract HIV are via unprotected sexual activity and the sharing of needles by users of intravenous drugs. The virus can also be transmitted from mother to unborn child. Blood transfusions and the use of blood products to treat hemophilia have also been major routes of infection in the past, leading to stricter screening procedures (but despite these new measures such cases are still reported occasionally).Prevention
HIV cannot be transmitted by breathing, via casual contact such as touching, holding or shaking hands, hugging, and kissing, or via mutual masturbation, or by sharing cooking and eating utensils, dishes, cups and glasses. The only proven cause of transmission is the exchange of bodily fluids.
HIV infection is preventable by following simple precautions.
HIV transmission via sexual activity has been recorded from male to male, male to female, female to female and female to male. The use of condoms is recommended for all penetrative sexual activity. (Note: condoms are not 100% effective against pregnancy or disease transmission. Nevertheless, after abstinence, they are considered one of the best means of protection against the spread of HIV). Anal sex, because of the delicacy of the tissues in the anus and the ease with which they can tear, is considered a high-risk activity, but condoms are recommended for vaginal sex as well. Condoms should be used only once, and then thrown away and a new condom used each time. Because of the risk of tearing, lubricants are recommended. Condoms are not compatible with oil-based lubricants. Use only water-based lubricants with condoms.
There have been claims that a small number of people have been infected with HIV from performing oral sex on an infected partner, but these claims are disputed in the scientific community and have yet to be proven conclusively. Oral sex is considered a very low risk activity, but it is recommended not to ingest or take ejaculate into the mouth. The use of condoms (or dental dams for cunnilingus) during oral sex further reduces the potential risk.
HIV is known to be transmitted via the sharing of needles by users of intravenous drugs. Do not share needles. Information on cleaning needles using bleach is available from health care and addiction professionals and from needle exchanges. A new needle should be used for each injection. Clean needles are available for free in some cities at needle exchanges or safe injection sites.
Medical workers who follow universal precautions or body substance isolation can prevent the spread of HIV from patients to workers, and from patient to patient. The risk of being infected with HIV from a single needlestick is less than 1 in 200. Post-exposure prophylaxis with anti-HIV drugs can further reduce that small risk.
HIV and AIDS
Not every patient who is infected with HIV is considered to have AIDS. The criteria for a diagnosis of AIDS can vary from region to region, but a diagnosis typically requires a minimum helper T cell count and the presence of opportunistic infections.
The helper T cell (thymus-derived cell or lymphocyte) count is a measure of the HIV target cells in the blood. A count below 200 per cubic millimetre is usually considered as one criterion for a diagnosis of AIDS. The occurrence of opportunistic infections (see below), caused by agents usually unable to induce diseases in healthy people, is another criterion. Helper cell counts can fluctuate, and opportunistic infections can sometimes be overcome, so a diagnosis of AIDS may be fluid.
A person who is infected with HIV is said to be HIV+ (HIV positive) and is sometimes referred to as a PWH, or Person With HIV. An uninfected individual is said to be HIV- (HIV negative). HIV+ individuals are frequently unaware of their seroconversion. Persons with AIDS (PWAs) are also sometimes said to be HIV+, and PWHs and PWAs are sometimes collectively referred to as PWAs or PWH/As.
Progression of the Disease
Infection with HIV is called seroconversion, and may be accompanied by mild flu-like symptoms such as fever, aching muscles and joints, sore throat, and swollen glands (lymph nodes), by other symptoms, or by no symptoms at all. Regardless of the presence or absence of initial symptoms, all newly infected individuals become asymptomatic (symptom-free).
During the asymptomatic stage, billions of HIV particles are produced every day accompanied by a decline (at variable rates) in the number of CD4 cells. The virus is not only present in the blood, but also throughout the body, particularly in the lymph nodes, brain, and genital secretions.
The time from HIV infection to the development of AIDS varies. Some patients develop symptoms in as little as 1 year after infection, while others are known to have remained completely symptom-free for as long as 20 years. The reason why different people advance at various rates is currently unkown. The average time for progression from initial infection to AIDS is 8 to 10 years absent treatment.
Description of Symptoms
HIV causes disease by infecting the CD4+ T cells (which are also called T4 cells or helper T cells). These are a subset of leukocytes (white blood cells) that normally coordinate the immune response to infection. T cells are part of the immune system and important in fighting infection and cancer. Once a HIV+ individual's CD4+ T cell count has decreased to a certain threshold, they are prone to a range of diseases that the body can normally control. These include cancers and opportunistic infections, which are usually the cause of death. HIV also infects brain cells, causing some neurological disorders.
AIDS defining illnesses
There are several accepted AIDS defining illnesses which include:
- candidiasis, oesophageal, lungs or disseminated
- coccidiodomycosis, disseminated or extrapulmonary
- cryptococcosis, extrapulmonary
- cryptosporidiosis, chronic intestinal
- cytomegalovirus (CMV) disease, disseminated or CMV retinitis
- herpes simplex virus (HSV) infection, chronic or HSV bronchitis, pneumonitis or esophagitis
- histoplasmosis, either disseminated or extrapulmonary
- isosporiasis, chronic intestinal
- mycobacterium avium complex infection or M. kansasii infection, disseminated or extrapulmonary mycobacterium tuberculosis, disseminated, any site
- Mycobacterium, other species, disseminated or extrapulmonary
- Pneumocystis carinii pneumonia (PCP)
- Salmonella septicemia, recurrent
- toxoplasmosis, neurological
- Kaposi's sarcoma
- lymphoma, Burkitt's or primary lymphoma of the brain
- HIV-related dementia or encephalopathy
Current Treatments and Vaccines
There currently no cure for AIDS. Newer treatments, however, have played a part in delaying the onset of AIDS, on reducing the symptoms, and extending patients' life spans.
Current treatment options primarily include combinations ("cocktails") of 2 nucleoside analogue reverse transcriptase inhibitors (NRTIs), and 1 protease inhibitor (pronounced "pro-tea-ace"). Patients on such treatments have been known to repeatedly test "undetectable" for HIV, but discontinuing therapy has thus far caused all such patients' viral loads to promptly increase. There is also concern with such regimens that drug resistance will eventually develop.
Ongoing research is examining methods of simplifying drug regimens (which often require patients to take large numbers of pills at prescribed intervals several times a day) to improve adherence and decrease side effects. New drugs are also being developed. Also, methods of purging HIV from the body are being researched.
Researchers are also attempting to create an HIV vaccine, and human trials are currently underway.
The majority of the world's infected individuals, unfortunately, do not have access to medications and treatments for HIV and AIDS.
Alternative theories
A few scientists continue to question the connection between HIV and AIDS, the very existence of HIV, or of an independent AIDS disease. The validity of current testing methods is also questioned. Dissident scientists report that they are usually not invited to attend AIDS conferences and are not granted research funding. Prominent members of this group are virus researcher Peter Duesberg and Nobel Prize laureate Kary Mullis. Their opponents often characterize their position as "AIDS denialism" and believe their public proselytization for their various theories is destructive to the adoption of appropriate preventive and therapeutic measures.
See AIDS reappraisal.
Current Status
As of the year 2002 AIDS is a global pandemic, and it shows no signs of slowing down. It is estimated that over 40 million people worldwide are HIV-positive and about 13 million have already died from AIDS-related disease, mainly tuberculosis. If such trends continue it is likely that the global death toll for AIDS will be comparable to other plagues such as the Black Death and the Spanish Flu.
In Western countries, the infection rate of HIV has slowed somewhat, due to education of safe sex practices. In some populations, however, such as young urban gay men, infection rates show signs of rising again. In Britain the number of people diagnosed with HIV increased 26% from 2000 to 2001. This is of major concern to public health workers. AIDS continues to be a problem with illegal sex workers and injection drug users. The death rate has also fallen considerably, as combinations of AIDS treatment drugs (often called "cocktails") have proven to be an effective (if expensive) means of suppressing HIV.
However in Third World countries (especially Sub-Saharan Africa), poor economic conditions (leading to the use of dirty needles in healthcare clinics) and lack of sex education means continued high infection rates. Some countries in Africa now have around 25% of the working adult population who are HIV-positive, the highest being Botswana with 35.8% (1999 estimate - source World Press Review). See AIDS in Africa.
AIDS is also rising steadily in Asia. As of July 2003, India's HIV-positive people numbered about 4.6 million, roughly 0.9% of the working adult population. In China the number was roughly from 1 million to 1.5 million, with some estimates going much higher. AIDS seems to be under control in Thailand and Cambodia, but new infections occur in those nations at a steady rate.
See also: AIDS in America, Homosexuality and medical science, AIDS quilt/NAMES project, List of HIV patients
Immunity
In 1983, FIV (Feline Immunodeficiency Virus) was discovered by Neils Pederson, doing research on a cat that seemed to be showing AIDS-like symptoms. A close relative of AIDS, it led to an immediate scare that it could spread to a number of wild cat species which are already endangered. Tests for the disease began on various African wild cat species. To the surprise of most involved, the disease was turning up everywhere. The infected wild cat species simply were not showing symptoms like the housecats were. This led to a high level of curiosity as to how the wild species were managing to be infected without this happening.
The initial theories - that the disease was remaining inactive in their systems, that the disease was only present in small amounts, or that the disease wasn't killing the cells that it infected - were all proven wrong. It turned out that the virus was present in huge quantities, and was killing many T-cells. Infected cats from species that didn't show symptoms, however, were simply replacing them as quickly as they were destroyed. It appeared that the wild cat species that were studied had a genetic adaptation to the disease. Housecats, which had not contracted the disease until recently, had no such immunity.
Despite the initial expectation of the researcher, it has since been determined that FIV has no particular relationship to HIV except in its name.
Research in primates has found a variable level of susceptibility to SIV between chimpanzees from different regions of Africa. This has profound implications for research on HIV, not only in ensuring equal natural resistance to the disease amongst laboratory animals. Although SIV and HIV have some similarities, humans can not be infected with SIV, and primates do not get sick from HIV.
In some parts of Africa, HIV infects more than one in every four people.
Prior reports of resistance in humans have proven disappointing in the end: For example, among populations of African prostitutes who were regularly exposed to the virus through unsafe sex practices, some apparently immune individuals were described during the early 1990s and made the subjects of intensive research into mechanisms of natural resistance. However, eventually, each woman in the study became infected with HIV, and no useful data was produced to help with a vaccine.
Similarly, a handful of babies born to HIV+ mothers were described at birth as being HIV+ and later tested negative. Subsequent studies have shown that the testing method was at fault, and these babies never were infected with HIV. The earlier studies checked for antibodies against HIV, not the virus itself, and -- like all other kinds of antibodies in breast-fed babies -- these infants tested positive on the basis of their mothers' antibodies, which had been transmitted to them during feeding.
Related Topics
- HIV
- AIDS in Africa
- AIDS in America
- AIDS conspiracy theories
- AIDS myths and urban legends
- AIDS quilt
- AIDS reappraisal
