AIDS

AIDS
AIDS was first conclusively identified in the United States in 1981, when 189 cases were reported to the Centers for Disease Control and Prevention. Within a decade the disease had spread to virtually all populated areas of the world. At the end of 2001, 40 million people worldwide were living with the AIDS virus. Roughly 70 percent of these lived in sub-Saharan Africa and 17 percent in South and Southeast Asia. Worldwide, almost 14,000 people are infected with HIV each day, with 95 percent of these new infections occurring in developing countries. HIV and AIDS are not limited by global economics, however—approximately 940,000 people in the United States and 560,000 people in Western Europe were living with HIV by the end of 2001; almost 5 percent of these infections were acquired that year. The region with the fastest rising rate of new HIV infections was Eastern Europe and Central Asia, where roughly 1 million people were positive for HIV by the end of 2001, a quarter of these newly infected that year.
The first AIDS patients in the Americas and Europe were almost exclusively male homosexuals. Later patients included those who used unsterilized intravenous needles to inject illicit drugs; hemophiliacs (persons with a blood-clotting disorder) and others who had received blood transfusions; females whose male sexual partners had AIDS; and the children of such couples. After 1989, heterosexual sex became the fastest growing means of transmission of the virus, with 80 percent of new adult cases worldwide originating from heterosexual sex. Approximately 44 percent of the people living with HIV/AIDS in 2001 were women.
Public awareness of the disease gradually increased as high-profile individuals died from the disease or revealed that they were infected with the AIDS virus. The fact that these public figures had diverse backgrounds and lifestyles helped negate the stereotypes that were associated with AIDS and demonstrated that anyone could be at risk for infection.
HIV: The AIDS Virus
The initial name given to the virus that causes AIDS was the human T-lymphotrophic virus type III (HTLV-III). In the late 1980s, scientists realized that there were several forms of the virus and renamed the original virus human immunodeficiency virus type 1 (HIV-1). Scientific evidence suggests that the virus originated in nonhuman primates, probably chimpanzees, in Africa.
The virus enters the bloodstream and destroys certain white blood cells called CD4+ cells, a type of T lymphocyte that plays a key role in the functioning of the immune system. The virus can also infect other types of cells in the body, including the immune-system cells known as macrophages. Unlike T lymphocytes, however, macrophages are not killed by the virus. Research has suggested that macrophages may carry HIV to the brain, leading to the syndrome of neurological disorders known as AIDS dementia complex (ADC) that is seen in some long-term patients.