Acquired immunodeficiency syndrome (AIDS) is the late stage manifestation of infection by the human immunodeficiency virus (HIV). The HIV virus lives in a type of immune cell (T-cell) which it destroys. Symptoms are sensitivity to opportunistic infections and/or malignancies and the mortality rate is very high, usually within 10 years of AIDS becoming manifest.
The syndrome results from a breakdown of the body's disease-fighting mechanism, the immune system, that leaves it defenceless against infections, such as pulmonary tuberculosis, Pneumocystis pneumonia, certain blood infections, candidiasis, invasive cervical cancer, Kaposi's sarcoma or any of over 20 other indicator diseases. The AIDS sufferer dies from one of these infections, compounded by general wasting and deterioration of body functions. No totally effective treatment is available, although promising drugs for remediation are available.
A striking feature of AIDS is the wide spectrum and frequency of life-threatening infections seldom seen in normal hosts. Four patterns of disease occur in AIDS patients. The pulmonary pattern, the central nervous system pattern, the gastrointestinal pattern and the pattern of fever of unknown origin. Most patients who recover from a given opportunistic infection subsequently either have a relapse or develop a new type of infection. Feelings of depression and isolation are common among AIDS patients and can be intensified if health care workers display fear of the syndrome.
AIDS takes ten years on average to develop. Because of this long lag time, AIDS cases will continue to develop from the existing pool of HIV-infected persons for some time to come, no matter how successful efforts are to curb the further spread of HIV.
Cases of acquired immune deficiency syndrome were first identified in the USA in 1981. There, AIDS was first called Gay-Related Immune Deficiency (GRID). By mid-1992, 6 US and 4 Spanish cases of AIDS symptoms without traces of the virus were found, which led scientists to question the existence of a third strain of HIV, thought to be similar to HIV1 and HIV2, but different enough to evade conventional HIV tests. The development of new HIV strains threatens to escape reliable modes of detection and preventative action.
Globally, there were an estimated 40 million people with AIDS in 2001, three-quarters of them in Africa. 37.2 million adults (17.6 million women) and 2.7 million children). 3 million died of AIDS in 2001 and another 5 million were newly infected. Cumulatively, 8.4 million people had died of AIDS by the end of 1996. The global incidences both for death and infection have been increasing at significant rates since AIDS was first detected in the 1980s. At the same time the geographic distribution of incidence has shifted. In 1997, the USA had a highest number of AIDS cases with 581,429; Brazil had 103,262; Tanzania had 82,174, Thailand 59,782, and France 45,395. Lately it is Africa, Asia and eastern Europe that have the most alarming infection and incidence numbers.
[Developed countries] A 1993 WHO report found that AIDS was the leading cause of death among men 25 to 44 years of age in 5 states and 64 cities of the USA. In 1997, AIDS became the leading cause of death among American blacks in this age bracket. Experts predict that the incidence of death due to AIDS will continue to rise in the black population, and that it will fall among the whites. American gay white males have adopted preventive measures such as condoms quite readily, while the black community of drug users has not yet faced the AIDS problem squarely.
The cost of AIDS to the USA, exclusive of administrations charges for worker's compensation, social security or health insurance benefits was $30 billion in 1992.
Indeed, the overall death rate due to AIDS in the USA fell by nearly half in 1997. France has the highest proportion of HIV positives in western Europe. Population groups predominantly affected during the 1980s were homosexual men and injecting drug users.
Increasing numbers of AIDS patients are now dying of hepatitis C (HVC). For example, cirrhosis of the liver has become the leading cause of death among AIDS patients in northern Italy. This is a corollary of better drugs and care. When the death rates from AIDS were higher, the HIV-infected did not live long enough to suffer the consequences of their hepatitis infection. A recent study of the 3,000 HIV-infected patients in the USA found that about 23.5 percent had both viruses. In some cities, 90 percent or more of injection drug users are infected with HCV.
There were 14,731 recorded cases of AIDS in the European Union in 1997, as against a record 24,294 cases in 1994 and over 20,000 in 1996. Spain was the EU country most affected by AIDS, with an incidence rate of 127.5 cases per million inhabitants in 1997. Finland was the least affected, with just 3.7 cases per million inhabitants. The EU average was 31.3 cases per million inhabitants. The largest transmission group in the EU in 1997 was of injecting drug addicts - they accounted for nearly 40% of diagnosed cases. Bisexual and homosexual males were next, with 35%. Some 10% to 15% of AIDS victims had contracted the disease through heterosexual contact. The origins of the disease in the remaining cases - fewer than 10% - could not be determined.
Whilst AIDS in the industrialized world fell in the later half of the 1990s, reflecting dramatic behaviour changes in the mid-1980s by the latter groups, heterosexual transmission has been increasing slowly but steadily during the second part of the 1980s and early 1990s and will dominate the continuing incidence of AIDS in the developed world.
With increasing penetration of AIDS into the heterosexual community, the incidence among women and children is growing rapidly. In 1997, 42% of HIV and AIDS cases worldwide were women. The chance of a man transmitting AIDS with a single unprotected sexual act to an uninfected woman is 1 in 100. If the woman has some other sexually transmitted disease, her chance of contracting AIDS in one session is 1 in 25. If the woman is infected and the man is not, the chance of transmission to the man is 1 in 1,000.
[Developing countries] AIDS has switched from being the disease of the industrialized world to the disease of the developing nations (1-20 million new infections were expected in adults during the 1990s, mostly in the developing world).
By the end of 1989 a cumulative total of 203,599 cases of AIDS had been reported from 152 countries to World Health Organization; by April 1991, over 345,000 cases has been reported from 162 countries; by 1993 the cumulative total had reached 718,894, but the estimated total was well over 2.5 million comprising (reported : estimated): (USA 40% : 13%, Africa 34.5% : 71%, Europe 13% : 5%, Americas (excluding USA) 11.5% : 9%, Asia 0.5% : 1%, other 0.5% : 1%). The estimated total takes into account the effects of less than complete case detection and reporting (very high in some countries), as well as reporting delay. WHO has estimated that the cumulative global total of adult AIDS cases developed by the year 2000 could reach ten million (other estimates as high as 24 million); with an annual death rate around 400,000; and with at least 40 million persons (30 million adults) infected with HIV-virus worldwide (this WHO estimate has close to doubled over the past five years, influenced to a considerable degree by the new latent pool of HIV infected persons in Asia; other estimates as high as 100 million). The global cost of AIDS treatment in 1990 was estimated to be between $2.6 billion and $3.5 billion - no more than 2% of which was spent in sub-Saharan Africa.
AIDS was the leading cause of death of children under 5 in Zimbabwe in 1995, being responsible for 25% of all children's deaths. By 2010, one third of the children in Zimbabwe will be orphaned by AIDS. More than half of Zimbabwe's soldiers have HIV or AIDS. Most of the Zimbabwean men dying from AIDS are in their 30's, most of the women in their 20's, and many girls are now dying in their teens.
Barring a miracle, Zimbabwe, Botswana, Zambia, Namibia and Swaziland will have lost one fifth or more of their adult population, from AIDS alone, by the end of the first decade of the 21st century. The social costs are enormous. Children are orphaned when their adult relatives die, and then are more vulnerable to sexual exploitation, which exposes them to AIDS. In parts of Africa, where transmission tends to be heterosexual, 3 new female cases arise for every new male case.
The incidence of AIDS in Latin America rose from fewer than 6,000 cases in 1987 to 60,000 in 1993. As in the rest of Latin America, it is known that 30-50% of the patients who have developed the disease are not reported. In Sao Paulo state, the number of people dying of AIDS quadrupled in four years, rising from 1,067 in 1987 to 4,134 in 1991. Similarly, in Mexico the number of AIDS cases rose from 245 in 1986 to 11,034 in 1992.
Productivity in developing economies is threatened. As the young sexually active members of the labour force (20-40) become infected, fewer will survive to form the older segment (40-60) which has accumulated skills. In Uganda, ten percent of the railway corporation's employees have died of AIDS; labour turnover is 15%. As of 1997, Malawi and Tanzania had already lost 30% of their school teachers via AIDS. In Zambia, one sample revealed 8% infection among urban adults with fewer than five years of schooling, rising to 33% of those with 14 years or more. Here the economic danger is in the country's copper mines, responsible for 75% of export earnings, that skilled workers, supervisors and managers will die of AIDS faster than replacements can be trained. In South Africa, life insurance companies paid £855,000 in AIDS-related claims between 1985 and 1988. In 1989 alone, payments were £700,000.