AIDS

AIDS (Acquired Immunodeficiency Syndrome or Acquired Immune Deficiency Syndrome, sometimes written Aids) is a global, human epidemic. The World Health Organization estimated that between 2.8 and 3.5 million people with AIDS died in 2004. An estimated 60% of cases occur in sub-Saharan Africa, where about half the cases are the result of medical procedures including blood transfusions [1]. AIDS is defined as occuring in people with antibodies to a retrovirus called Human Immunodeficiency Virus (HIV), which is thought to have originated in African monkeys and passed to human populations during the twentieth century. A diagnosis of AIDS is made when a person with HIV antibodies has either a CD4 cell count below 200 or one of a list of AIDS-defining illnesses, which are unusual in a person with a healthy immune system. [2]

In October 1985, a conference of public health officials including representatives of the Centers for Disease Control and World Health Organization met in Bangui to develop a definition of AIDS for use in countries where testing for HIV antibodies was not available. They developed the Bangui definition which defines AIDS as, "prolonged fevers for a month or more, weight loss of over 10% and prolonged diarrhoea". About half the people diagnosed with AIDS based on the Bangui definition have antibodies to HIV when tested.

1 AIDS epidemic
2 Symptoms
3 Treatment
4 Prevention
5 Origins of AIDS
6 Current medical understanding of AIDS
7 Alternative theories
8 Current status
9 Related diseases
10 See also
11 Compare
12 External links

AIDS epidemic

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

UNAIDS and the World Health Organization estimated that between 39 and 44 million people around the world were living with HIV/AIDS in December 2004 (source). 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.

Since 1981 of an estimated 80 million people with HIV infection worldwide an estimated 23 million people have died. In Africa, the most common cause of death for people with AIDS is Tuberculosis.

AIDS was first noticed in 1978 among homosexual men but widespread knowledge about the disease was not available until the 1980s. The term AIDS (acquired immunodeficiency syndrome) was proposed on July 27,1982 at a meeting in Washington of gay-community leaders, federal bureaucrats and the Centers for Disease Control and Prevention (CDC). [3] The identified risk factors for AIDS were hemophilia, Haitian, male homosexual, or intravenous drug abuser. In 1985 the definition of AIDS was restricted to exclude people who did not have antiboides to HIV and in 1993 the definiton was expanded to include people with antiboides to HIV and low T cell counts.

By the 1990s the syndrome had become a global pandemic and in 2004, 58 percent of those with AIDS were women. While men who have sex with men and those of African descent have higher per capita AIDS rates, the majority are currently heterosexual women and men, and children in developing countries. Those who have sex without condoms, especially anal intercourse, or use injectable drugs are at the highest risk of transmission.

Symptoms

The first symptoms of AIDS are opportunistic infections, that are not usually seen 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 cell count is less than 200. The CDC defines the beginning of AIDS as when a person with HIV (human immunodeficiency virus) has either a CD4 cell count below 200 or one of numerous opportunistic infections, which are unusual in a person with a healthy immune system. [4]

The time from infection with HIV to a diagnosis of AIDS varies. A person who has been living with HIV for at least 7 to 12 years and has a stable CD4 cell count above 600, no opportunistic infections, and no previous antiretroviral medication is called a long-term nonprogressor.

Treatment

HIV is a chronic medical condition that can be treated, but not yet cured. There are effective means of preventing complications and delaying, but not preventing, progression to AIDS.

People with HIV infection need to receive education about the disease and treatment so that they can be active partners in decision making with their health care provider.

The current guidelines for antiretroviral therapy from the World Health Organization reflect the changes to the guidelines to defer retroviral treatment in patients with no symptoms who have a CD4 cell count above 350 and viral load under 100,000.

Antiretroviral regimens are complex, have serious side effects, pose difficulty with adherence, and carry serious potential consequences from the development of viral resistance because of nonadherence to the drug regimen or suboptimal levels of antiretroviral agents. Patient education and involvement in therapeutic decisions are critical. Treatment should usually be offered to all patients with symptoms ascribed to HIV infection. Recommendations for offering antiretroviral therapy among asymptomatic patients require analysis of real and potential risks and benefits. Panel on Clinical Practices for Treatment of HIV. September 2002

HAART (highly-active anti-retroviral therapy) is commonly used to describe a combinations 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).

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.

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.

Prevention

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. The rate of mother-to-infant transmission can be cut dramatically when appropriate medical precautions, including the administration of antiretroviral medications, are observed.

HIV blood screening

Blood tranfusions remain a major source of new HIV infections worldwide. WHO estimated in 2000, between 15% and 20% of new HIV infections worldwide were the result of blood transfusions, where the donors were not screened or inadequately screened for HIV. 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

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

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.

Vaccine research

There is ongoing research into developing a vaccine for HIV. 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. 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.

Chemokines

In 1996, Robert Gallo published his discovery that chemokines, a class of naturally occurring compounds, can block HIV and halt the progression of AIDS. This was heralded as by Science magazine as one of the top scientific breakthroughs within the same year of his publication, but has yet to result in any actual therapetic benefits. reference

The role of protection chemokines plays for controlling progression of HIV infection to AIDS has been influencing medical thinking on how AIDS works against the human body. It is regarded as having great potential in playing a future role in possible vaccine development. 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". Proc Natl Acad Sci U S A 96 (21): 1198611991.

Safer sex

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 infected male to female in a single act of genital sex are quite low: it is estimated that under normal conditions, only about 1 in 1000 acts results in infection. However, this rate is significantly higher if the healthy 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. Transmission of virus from females to males is even less likely, but still possible.

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

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." [5]. Although condoms are not completely guaranteed to prevent pregnancy or sexually transmitted disease(STD)), it has been repeatedly verified that HIV transmission during intercourse is preventable by the use of latex condoms. Major brand condom manufacturers subject their product to electrical-level testing to ensure they will prevent bodily fluid transmission on the microscopic level. Despite the orderly way condoms come packaged, the quality of condoms at the time of their manufacturing date does not last indefinitely; aging condom packages that have never been opened cannot promise that their contents are not subject to higher risk of microscopic tearing.

Anal sex, perhaps because of the risk of anal tissue tearing, is the riskiest form of sexual activity for transmitting the virus despite the use of condoms; and condoms are recommended for vaginal sex as well. Water-based lubricants reduce the risk of the condom tearing during sexual activity. Oil-based sexual lubricants should not be used with condoms as they can cause tears in the condom material by weakening the latex.

Oral sex carries less risk HIV transmission than does genital and anal sex. 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.

Intravenous drug use

HIV can 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.

Origins of AIDS

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.

Studies suggest that the virus initially spread from West Africa. It is possible that there were several initial sources corresponding to different strains of HIV (HIV-1 and HIV-2). The sample fluid earliest known for human-carrier was from 1959, which derived from a British sailor; he contracted it in what is now the Democratic Republic of the Congo. 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.

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.

Current medical understanding of AIDS

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 and injecting drug use remain prominent sources of new HIV infections, though the fastest growing group is African-American women. Antiretroviral drugs, cesarean delivery and formula feeding are widely promoted to reduce the transmisison of HIV from mother to child.

Studies have shown that about half the people in Africa defined by defective WHO criteria as having AIDS are in fact not infected with HIV and therefore may respond to treatment with antibiotics and improved nutrition.

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

The overwhelming scientific consensus is that HIV causes AIDS. However, a small number of scientists and activists question the connection between HIV and AIDS, or the existence of HIV, or the validity of current testing methods.

Current status

AIDS is a worldwide epidemic . 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 [6]. The majority of AIDS cases occur in Sub-Saharan Africa having 68% of the adult population infected. South & South East Asia are secondly most affected holding 15% of AIDS cases globally. Children deaths account to figures of 500,000. These statistical figures have led experts to say this is the deadliest pandemic in human history comparable to the Black Death; Black Death ravaged Europe and western Asia during the 14th century-- 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. The spread of infection among heterosexuals in western countries has also been much decelerated more than fearfully anticipated, partially suspected by the notion that HIV is less readily transmissible through vaginal sex without other concurrent sexually transmitted diseases. Even in some metropolitan areas with large gay communities(notably San Francisco, United States where 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. 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, 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(age?) population is HIV-positive; in Botswana alone the figure was 35.8% (1999 estimate — source World Press Review). The situation in South Africa, where President Thabo Mbeki shares the beliefs of "AIDS denialists," is a negative influence and neglection of the fact that 4.7 million infections took place for 2002. Also heavily affected are Nigeria-3.7 million and Ethiopia-2.4 million for 2003. On the other hand Uganda, Zambia, and Senegal have began executing programming intervention measures to decelerate HIV spreading and have received positive feedback.

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.

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.