| AIDS (acquired immune deficiency syndrome, sometimes written Aids) has been defined by the Centers for Disease
Control has as beginning when a person with HIV infection has a CD4 cell (also called "t-cell", a type of immune cell) count below 200. It is also defined by numerous
opportunistic infections, which are infections that
do not normally develop in a person with a healthy immune system.
In October 1985, a conference of public health officials including representatives of the Centers for Disease Control and World Health Organisation met in Bangui and defined AIDS in Africa as, "prolonged fevers for a month or more, weight loss of over 10% and
prolonged diarrhoea". About half the AIDS cases in Africa based on the Bangui
definition are HIV positive.
There is no cure for AIDS at this time. However, several treatments are available that can delay the progression of disease
for many years and improve the quality of life of those who have developed symptoms. There is good evidence that if the levels of
HIV remain suppressed and the CD4 count remains
greater than 200, then life and quality of life can be significantly prolonged and improved.
In 1996, Robert Gallo's discovery
that a natural compound known as chemokines can block HIV and halt the progression of AIDS was hailed by Science magazine as one of that year's most
important scientific breakthroughs. reference (http://www.ihv.org/bios/gallo.html)
The World Health Organization estimated that 3
million people with AIDS died in 2004.
Symptoms of AIDS
The first symptoms of AIDS are opportunistic
infections, that do not normally develop in individuals with healthy immune systems. People who have been exposed to HIV are encouraged to
have an HIV test, so that the health of their immune system can be monitored and antiretroviral treatment offered before their CD4 count is
less than 200.
CD4+ helper T cells, are a
type of white blood cell (or leukocyte) that normally
coordinates the immune response to infection and cancer. A person with a CD4+ T cell count of less than 200 is prone to
diseases that a healthy person's body is normally able to resist. These diseases include cancers and opportunistic infections.
Originally AIDS was diagnosed based on the opportunistic diseases affecting the patient. Since 1993, in the United States about two thirds of new AIDS diagnoses are based on CD4+ T cell
counts of less than 200.
Origins of AIDS
AIDS was first reported as opportunistic
infections among gay male intravenous drug users in the 1980s and called GRID (Gay Related Immune Deficency). Similar opportunisitic infections were
reported in men with haemophilia and men from Haiti. By the 1990s AIDS cases have been reported around the world in men,
women and children. Studies of AIDS in Africa suggest that about half these cases are probably associated with HIV infection.
Studies suggest that the virus spread initially in West Africa, but it is
possible that there were several separate initial sources, corresponding to the different strains of HIV (HIV-1 and HIV-2). The
earliest human fluid sample known to contain HIV was taken in 1959 from a British sailor, who apparently contracted it in what is now the Democratic Republic of the Congo. Other
early samples include one from an American male who died in 1969, and a Norwegian sailor in 1976. The earliest documented western
death from AIDS was Dr. Grethe Rask, a Danish surgeon, who worked in the
Congo in the early 1970s.
The OPV AIDS hypothesis argues that the origin of AIDS is
the oral polio vaccination program in Africa during the late 1950s.
Current medical understanding of AIDS
The role of chemokines in protection from progression of HIV infection to AIDS is changing the medical understanding of AIDS. Alfredo Garzino-Demo, Ronald B. Moss, Joseph
B. Margolick, Farley Cleghorn, Anne Sill, William A. Blattner, Fiorenza Cocchi, Dennis J. Carlo, Anthony L. DeVico, and Robert C. Gallo (October 1999) "Spontaneous and antigen-induced
production of HIV-inhibitory β-chemokines are associated with AIDS-free status (http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=18399&rendertype=abstract)".
Proc Natl Acad Sci U S A 96 (21), 11986–11991.
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 either:
- an absolute CD4 cell count below 200 per cubic centimeter, or
- the presence of "opportunistic" infections, caused by agents usually unable to induce diseases in healthy people
A person who is infected with HIV is said to be HIV positive (or seropositive). An
uninfected individual is said to be HIV negative (or seronegative). HIV positive individuals are frequently unaware of their HIV
status.
Studies have shown that about half the people in Africa diagnosed with AIDS are not infected with HIV and therefore may respond to treatment with antibiotics and improved nutrition.
The time from infection with HIV to a diagnosis of AIDS varies. Some patients develop
symptoms within a few months of infection, while others are known to have remained completely asymptomatic for as long as 20
years. People who remain asymptomatic for 7 to 12 years and maintain a CD4 count of 600+, with no HIV-related illnesses or
antiretroviral treatment are often called HIV long-term
nonprogressors [1] (http://aidsinfo.nih.gov/ed_resources/glossary/default.asp?id=467&letter=l). Why these
nonprogressors remain AIDS-free, and why different people advance at various rates, is currently unknown. The average time of
progression from initial infection to AIDS is 8 to 10 years.
Treatments and vaccines
There is currently no cure or vaccine for HIV or AIDS. Newer treatments, however, have played a part in delaying the onset of
AIDS, fully eliminating the HIV virus from those recently exposed, on reducing the symptoms, and extending patients' life spans.
Over the past decade the success of these anti-retroviral treatments in prolonging, and improving, the quality of life for people
with AIDS has improved dramatically.
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). Patients on such treatments have been known to repeatedly test "undetectable"
(that is, negative) 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. In recent years the term HAART (highly-active anti-retroviral therapy) has been commonly used to describe this form of
treatment. The majority of the world's infected individuals, unfortunately, do not have access to medications and treatments for
HIV and AIDS.
There is ongoing research into developing a vaccine for HIV and in
developing new anti-retroviral drugs. Human trials are currently underway. Gene
therapy has also been suggested as a possible approach to preventing or treating HIV infection. 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.
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.
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 PWAs experimented with alternative therapies of various kinds, including massage, herbal and flower remedies and acupuncture, to either combat the virus or to relieve related symptoms. None of these
were shown to have any genuine or long-term effect on the virus in controlled trials, but they may have had other quality of
life-enhancing effects on individual users. Interest in these therapies has declined over the past decade as conventional
treatments have improved. They are still used by some people with AIDS who do not believe that HIV causes AIDS. Alternative
therapies such as massage, acupuncture and herbal medicine are still used by many sufferers in conjunction with other treatments,
mainly to treat symptoms such as pain and loss of appetite. People with AIDS, like people with other illnesses such as cancer, also sometimes use marijuana to treat
pain, combat nausea and stimulate appetite.
In 2005 the Centers for Disease Control and Prevention in the United States recommended a 28 day HIV drug regimen for those who believe they may have had contact
with the virus. The drugs have been shown to be effective in preventing the virus nearly 100% of the time in those who received
treatment within the initial 24 hours of exposure. The effectively falls to 52% of the time in those who are treated within 72
hours; those not treated within the first 72 hours are not recommended candidates for the regimen.
Alternative theories
Main article: AIDS reappraisal
A few scientists and AIDS activists 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 from most mainstream sources. Prominent
members of this group are virus researcher Peter Duesberg and Nobel Prize laureate Kary Mullis.
These theories have been in the field for at least 15 years, and have found little support beyond the original circle of
advocates. They gained prominence when they were promoted, for reasons which have never been made clear, by sections of the
Murdoch press, such as the Sunday Times and The Australian.
Dr. Robert E. Willner
caught the attention of the Spanish media, when in 1994 he inoculated himself with the
blood of Pedro Tocino, an HIV positive hemophiliac on live TV. Dr. Willner died
of a heart attack in 1995.
Mainstream AIDS activists characterize the position of these dissidents as "AIDS denialism," and believe their public proselytization for their various theories is destructive to the
adoption of appropriate preventive and therapeutic measures. Advocates of these theories include elements within some African
countries and some gay rights groups, such as ACT-UP in San Francisco. South African president Thabo Mbeki famously made a speech questioning the causal link between AIDS and HIV.
As with the enthusiasm for alternative therapies, advocacy of unorthodox views about AIDS has declined with the increasing
success of orthodox medical approaches to AIDS therapies.
Current status
AIDS is a global epidemic that exists in every continent. UNAIDS estimates that in
2004, 39.4 million people were infected with AIDS, 3.1 million died due to AIDS (with a
total of 19 million dead since 1980) and
4.9 million were newly infected with HIV [2] (http://www.unaids.org/wad2004/report.html). The majority of AIDS cases occur in Sub-Saharan
Africa, in which 8% of the adult population is infected. South & South East Asia are the second most affected areas, with 15%
of global AIDS cases. Children accounted for 500,000 of the AIDS deaths. These numbers have led some experts to call AIDS the
deadliest pandemic in human history since the Black Death that ravaged Europe
and western Asia in the 14th century and the introduction of smallpox and other
Eurasian diseases to the Americas in the 16th century.
In Western countries the infection rate of HIV has slowed somewhat, due to the widespread adoption of safe sex practices by most of the sexually active population (including gay men) and (to a lesser extent)
the existence of needle exchanges and campaigns to educate
intravenous drug users about the dangers of sharing needles. The spread of infection among heterosexuals in western countries has
also been much slower than originally feared, possibly because HIV is less readily transmissible through vaginal sex without
other concurrent sexually transmitted
diseases than was initially believed. Even in some major population areas with large gay communities such as San Francisco, United
States, AIDS cases have fallen to levels not seen since the original outbreak; many attribute this to aggressive educational
campaigns.
In some populations, however, such as young urban gay men of African descent and the African-American community at large,
infection rates began to show signs of rising again from the late 1990s. In Britain the number of people diagnosed with HIV increased 26% from 2000 to 2001. Similar trends have been seen in the United
States and Australia, and are attributed 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 developing countries, in particular Sub-Saharan Africa, however, poor economic conditions (leading to the use of dirty
needles in healthcare clinics) and lack of sex education means continued
high infection rates (see AIDS in Africa). In some countries in
Africa 25% or more of the working adult population is HIV-positive; in Botswana alone the figure is 35.8% (1999 estimate
— source World
Press Review (http://www.worldpress.org/map.htm)). The situation in
South Africa, where President Thabo Mbeki shares the views of the "AIDS denialists," is also deteriorating rapidly, with 4.7 million
infections in 2002. Also suffering heavily are Nigeria and Ethiopia, which had 3.7 million and 2.4 million people
infected respectively in 2003. On the other hand Uganda, Zambia, and Senegal
have initiated prevention programs to reduce their HIV infection rates, with varying degrees of success.
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 the AIDS virus 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.
Prevention
Despite widely publicised fears about the possible "casual transmission" of HIV and AIDS, the risk of infection is virtually
eliminated by following simple precautions, such as abstaining from sexual activity outside a definitely monogamous relation with a seronegative partner, and avoiding blood transfusions with unsafe blood.
The only proven cause of transmission is the exchange of bodily fluids, in particular blood and genital secretions. HIV cannot
be transmitted by breathing, via casual contact such as touching, holding or shaking hands, by sharing cooking and eating
utensils, dishes, cups and glasses, hugging and kissing, or by mutual masturbation. It is possible that HIV could be transmitted through open-mouthed kissing if both partners had
bleeding oral sores, but no such case has been documented and the possibility of transmission in this way is considered very
unlikely as saliva contains much lower concentrations of HIV than, for example,
semen.
HIV is not a hardy virus; the virus dies within about twenty minutes once it is outside a human body. Thus, for example blood
or semen stains quickly become non-infectious and are no cause for concern.
HIV transmission via sexual activity has been recorded from male to male, male to female, female to female and female to male.
"Health experts around the world urge people to use condoms to protect themselves from HIV and a host of sexually transmitted
infections." [3] (http://news.bbc.co.uk/1/hi/health/3176982.stm). Although condoms are not 100% effective
against pregnancy or disease transmission, it has been repeatedly shown that HIV cannot pass through latex condoms. All major brand condoms are electrically tested during production to ensure they have no microscopic
holes. However packaged condoms do not last indefinitely, old condoms have a higher risk of tearing, thus they should not be used
after the date given on the package.
Anal sex, because of the delicacy of the tissues in the anus and the ease with which they can tear, is considered the highest-risk sexual activity, but condoms are
recommended for vaginal sex as well. Condoms should be used only once and
then be disposed of. Because of the risk of tearing (both of the condom and of skin and mucous membranes), the use of water-based
lubricants is recommended. Oil-based sexual lubricants should not
be used with condoms as they can cause tears in the condom material by weakening the latex.
In terms of HIV transmission, oral sex is considered a lower risk than vaginal
or anal sex. The relative lack of definitive research on the subject, coupled with conflicting public information and cultural
influences have caused many to believe, incorrectly, that oral sex is safe. Although the actual risk factor of oral HIV
transmission is unknown, there are documented cases of HIV transmission through both insertive and receptive (male) oral sex. One
study concluded that 7.8% of recently infected men in San Francisco were probably infected through oral sex. However, a study of
Spanish men who knowingly engaged in oral sex with HIV+ partners identified no cases of oral transmission. Part of the reason for
such apparently conflicting evidence is that identifying oral transmission cases is problematic. Most HIV+ persons engaged in
other types of sexual activity prior to infection, thus making it difficult or impossible to isolate oral transmission. Factors
such as mouth sores, etc., are also difficult to decouple from transmission between "healthy" persons. It is usually recommended
not to take semen or preseminal fluid into the mouth. The use of condoms for oral sex (or dental dams for cunnilingus)
further reduces the potential risk.
HIV is known to be transmitted via the sharing of needles by users of intravenous drugs, and this is one of the most common
methods of transmission. 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.
Medical workers who follow universal precautions or
body substance isolation such as wearing latex gloves when giving injections or handling bodily wastes or fluids, and washing the
hands frequently, 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 prick with a needle that has been used on an HIV infected person is thought to be less than 1 in 200.
Post-exposure prophylaxis with anti-HIV drugs can
further reduce that small risk.
Several studies have shown that circumcised men may be
slightly less likely to contract HIV. Alternatively, there are studies which show nations with high circumcision rates have more
AIDS overall than those with low rates. One theory is that cells in the foreskin,
which are removed during circumcision, act as so-called "HIV receptors". The difference at present appears to be very slight, and
could be a result of cultural and hygiene differences rather than circumcision. It is unlikely that these findings will lead to
an increase in circumcisions carried out on newborns, which are currently performed on most infant boys in the United States.
Being circumcised should not be taken as having immunity to HIV.
There is now some evidence that treatment of already-infected people with antiretroviral drugs may reduce the transmission of
HIV infection to their sexual partners, independently of other safer-sex precautions [4] (http://news.bbc.co.uk/1/hi/health/3538556.stm). This may imply that aggressively treating
existing HIV cases, in addition to protecting the uninfected population through education and safer-sex programs, may be more
effective at preventing the spread of HIV than either of these alone.
Related diseases
Many opportunistic diseases are associated with AIDS:
- Candidiasis, disseminated or of the oesophagus and/or lungs
- 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
- HIV-related dementia or encephalopathy
- Kaposi's sarcoma (KS) and Kaposi's sarcoma-associated
herpesvirus-related diseases including primary effusion and multicentric Castleman's disease
- Chronic intestinal isosporiasis
- AIDS-related lymphoma, Burkitt's or primary lymphoma
of the brain
- Mycobacterium avium complex
(MAC) infection or M. kansasii infection, disseminated or extrapulmonary Mycobacterium tuberculosis, disseminated, any site
- Mycobacterium, other species, disseminated or extrapulmonary
- Pneumocystis carinii
pneumonia (PCP)
- Progressive
multifocal leukoencephalopathy (PML)
- Recurrent salmonella septicaemia
- Neurological toxoplasmosis.
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