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Acquired Immune Deficiency Syndrome (AIDS) has led to the deaths of more than 25 million people since it was first recognized in 1981, making it one of the most destructive epidemics in recorded history. Despite recent improved access to antiretroviral treatment and care in many regions of the world, the AIDS epidemic claimed approximately 2.1 million (between 1.9 and 2.4 million) lives in 2007.
The pandemic is not homogeneous within regions with some countries more afflicted than others. Even at the country level there are wide variations in infection levels between different areas. The number of people living with HIV continues to rise in most parts of the world, despite strenuous prevention strategies. Sub-Saharan Africa remains by far the worst-affected region, with 20.9 million to 24.3 million people living with HIV at the end of 2007. Sixty-eight percent of all people living with HIV are in sub-Saharan Africa, as are more than 77% of all women living with HIV. South & South East Asia are second most affected with 15%.
The key facts surrounding this origin of AIDS are currently unknown, particularly where and when the pandemic began, though it is said that it originated from the apes in Africa. 
Additional recommended knowledge
An overview of regions with large infected populations
Source: UNAIDS 2007 estimates. The ranges define the boundaries within which the actual numbers lie, based on the best available information. 
Sub-Saharan Africa remains the hardest-hit region. HIV infection is becoming endemic in sub-Saharan Africa. It is home to just over 10% of the world’s population but more than 60% of all people living with HIV worldwide reside here. The adult (15-49) HIV prevalence rate is 7.2% (range: 6.6 - 8.0%) with between 20.9 million and 24.3 million people currently living with HIV. However, it must be noted that the actual prevalence does vary between regions. Presently, Southern Africa is the hardest hit region, with adult prevalence rates exceeding 20% in most countries in the region, and even 30% in Swaziland and Botswana. Eastern Africa also experiences relatively high levels of prevalence with estimates above 10% in some countries, although there are signs that the pandemic is declining in this region, notably in Uganda which previously recorded one of the highest prevalence rates on the continent. West Africa on the other hand has been much less affected by the pandemic, several countries reportedly have prevalence rates around 2-3% and no country has yet rates above 10%, although in two of the region's most populous countries, Nigeria and Côte d'Ivoire, between 5 and 7% of adults are reported to carry the virus. 
Across Sub-Saharan Africa, more women are infected with HIV than men, with 13 women living with HIV for every 10 infected men and the gap continues to grow. Throughout the region, women are being infected with HIV at earlier ages than men. The differences in infection levels between women and men are most pronounced among young people (aged 15–24 years). In this age group, there are 36 women living with HIV for every 10 men. The widespread prevalence of sexually transmitted diseases, the practice of scarification, transfusion, and the poor state of hygiene and nutrition in Africa may all be facilitating factors in the transmission of HIV-1 in this region (Bentwich et al., 1995). In 2000, the World Health Organization estimated that 25% of the units of blood transfused in Africa were not tested for HIV, and that 5–10% of HIV infections in Africa were transmitted via blood .
Poor economic conditions (leading to the use of dirty needles in healthcare clinics) and lack of sex education contribute to high rates of infection. In some African countries, 25% or more of the working adult population is HIV-positive.
In South Africa, President Thabo Mbeki has questioned in the past the connection between HIV and AIDS - instead hinting at the possibility of factors such as undernourishment being one of the causes of the disease. While South Africa has created preventative programs and research initiatives to address its HIV problem, critics charge that the South African government has been slow to create antiretroviral programs and take other effective medical steps to stop the epidemic. UNAIDS estimates that in 2005 there were 5.5 million people in South Africa living with HIV — 12.4% of the population. This was an increase of 200,000 people since 2003.
Although HIV infection 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. On the other hand, Uganda, Zambia, Senegal, and most recently Botswana have begun intervention and educational measures to slow the spread of HIV, and Uganda has succeeded in actually reducing its HIV infection rate
Middle East and North Africa
The prevalence in this area is 0.2% (0.1-0.7%), with between 230,000 and 1.4 million people infected, however these numbers are debated. In this area, the routes of transmission of HIV are diverse; they include rape and consentual sex, relations that are homosexual and heterosexual in nature, and individuals who regularly participate in injected drug use. Among young people 15–24 years of age, 0.3% of women [0.1–0.8%] and 0.1% of men [0.1–0.3%] were living with HIV by the end of 2004.
South and South-East Asia
The HIV prevalence rate across this region is less than .35 percent. Due to the population size this brings the total of HIV infections to 4.2 - 4.7 million adults and children. More AIDS deaths (480,000) occur in this region than any other region except sub-Saharan Africa. This sprawling region is not just vast but diverse, with the nature, pace and severity of HIV epidemics differing across the region. The AIDS picture in South Asia is dominated by the epidemic in India, but new data released by UNAIDS shows that India as of 2007 has a relatively low Aids prevalence rate. With an estimated 2-3.1 million infections, India has the third largest number of people with aids after South Africa and Nigeria.  In South and Southeast Asia, the HIV epidemic remains largely concentrated in injecting drug users, men who have sex with men, sex workers, and clients of sex workers and their immediate sexual partners. New infections occur in Thailand and Cambodia at a steady rate. Prevention strategies in these populations are, for the most part, inadequate.
The national HIV prevalence levels in East Asia is 0.1% in the adult (15-49) group. However, due to the large populations of many East Asian nations, this low national HIV prevalence still means that large numbers of people are living with HIV. The picture in this region is dominated by China. Much of the current spread of HIV in China is through injecting drug use and paid sex. In China, the number was estimated at between 430,000 and 1.5 million by independent researchers, with some estimates going much higher. In the rural areas of China, where large numbers of farmers, especially in Henan province, participated in unclean blood transfusions; estimates of those infected are in the tens of thousands. In Japan, just over half of HIV/AIDS cases are officially recorded as occurring amongst homosexual men, with the remainder occurring amongst heterosexuals and also via drug abuse, in the womb or unknown means.
In this region, only Guatemala and Honduras have national HIV prevalence of over 1%. In these countries, HIV-infected men outnumber HIV-infected women by roughly 3:1. Lower prevalence in other countries disguises serious, localized epidemics. 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 accounts for more than a third of all HIV infections in Latin America, with the routes of transmission including paid sex, sex between men and injecting drug use. Brazil began in the 1980s a comprehensive AIDS prevention and treatment programme to keep AIDS in check, including the production of generic versions of anti-retroviral drugs.
The Caribbean is the second-most affected region in the world. Among adults aged 15–44, AIDS has become the leading cause of death. The adult prevalence rate is between 1.1% and 2.7%. HIV transmission occurs largely through heterosexual intercourse, with two thirds of AIDS cases in this region attributed to this route. Sex between men is also a significant route of transmission, even though it is heavily stigmatised and illegal in many areas. HIV transmission through injecting drug use remains rare, except in Bermuda and Puerto Rico.
Eastern Europe and Central Asia
There is also growing concern about a rapidly growing epidemic in Eastern Europe and Central Asia, where an estimated 0.99-2.3 million people were infected in December 2005, though the adult (15-49) prevalence rate is low (0.9%). The rate of HIV infections began to grow 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. The epidemic is still in its early stages in this region, which means that prevention strategies may be able to halt and reverse this epidemic. However, transmission of HIV is increasing through sexual contact and drug use among the young (<30 years). Indeed, over 80% of current infections occur in this region in people less than 30 years of age.
In most Western countries, AIDS cases have fallen to levels not seen since the original outbreak; many attribute this trend to aggressive educational campaigns, screening of blood transfusions and increased use of condoms. Also, the death rate from AIDS in Western Europe has fallen sharply, as new AIDS therapies have proven to be an effective (if expensive) means of suppressing HIV.
In this area, the routes of transmission of HIV is diverse, including paid sex, sex between men, injecting drug use, mother to child and heterosexual sex. However, many new infections in this region occur through contact with HIV-infected individuals from other regions. The adult (15-49) prevalence in this region is 0.3% with between 570,000 and 890,000 people currently living with HIV. Due to the availability of antiretroviral therapy, AIDS deaths have stayed low since the lows of the late 1990s. However, in some countries, a large share of HIV infections remain undiagnosed and there is worrying evidence of antiretroviral drug resistance among some newly HIV-infected individuals in this region. Also, there has been a recent increase in risky behavior among men who have sex with men.
The adult prevalence rate in this region is 0.7% with over 1 million people currently living with HIV. In the United States, sex between men (with and without concurrent needle drug use) represents 71% of new cases, high risk heterosexual sex (which includes sex with a partner known to have HIV) is 15% and needle sharing by intravenous drug users is 12% of new cases. . Currently, rates of HIV infection in the US are highest in the eastern and southern regions, with the exception of California. Currently, between 35,000 to 40,000 new infections occur in the USA every year. AIDS is one of the top three causes of death for African American men aged 25–54 and for African American women aged 35–44 years in the United States of America. In the United States, African Americans make up about 48% of the total HIV-positive population and make up more than half of new HIV cases, despite making up only 12% of the population. AIDS continues to be a problem with illegal sex workers and injecting drug users. The main route of transmission for women is through heterosexual sex, and the main risk factor for them is non-protection and the undisclosed risky behavior of their sexual partners. African American women are 19 times more likely to contract HIV than white women . Experts attribute this to "AIDS fatigue" among younger people who have no memory of the worst phase of the epidemic in the 1980s and early 1990s, 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.
In the United States in particular, a new wave of infection is being blamed on the use of methamphetamine, known as crystal meth. 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 anal sex . In addition, several renowned clinical psychologists now cite methamphetamine 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 methamphetamine 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 United States report anecdotal evidence that 75% of new HIV seroconversions they deal with are methamphetamine-related; indeed, in Los Angeles, methamphetamine is regarded as the main cause of HIV seroconversion among gay men in their late thirties. The First National Conference on Methamphetamine, HIV and Hepatitis took place in Salt Lake City in August of 2005.
On the other hand, as in Western Europe, the death rate from AIDS in North America has fallen sharply, as new AIDS therapies have proven to be an effective (if expensive) means of suppressing HIV.
There is a very large range of national situations regarding AIDS and HIV in this region. This is due, in part, to the large distances between the islands of Oceania. The wide range of development in the region also plays an important role. The prevalence is estimated at between 0.2% and 0.7%, with between 45,000 and 120,000 adults and children currently living with HIV.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "AIDS_pandemic". A list of authors is available in Wikipedia.|