AIDS

The symptoms of AIDS are primarily the result of conditions that do not normally develop in individuals with healthy immune systems. Most of these conditions are infections caused by bacteria, viruses, fungi and parasites that are normally controlled by the elements of the immune system that HIV damages.

AIDS stands for acquired immunodeficiency syndrome. AIDS is the final stage of HIV infection. It can take years for a person infected with HIV, even without treatment, to reach this stage. Having AIDS means that the virus has weakened the immune system to the point at which the body has a difficult time fighting infection. When someone has one or more specific infections, certain cancers, or a very low number of T cells, he or she is considered to have AIDS.

Origin of HIV

Scientists identified a type of chimpanzee in West Africa as the source of HIV infection in humans. The virus most likely jumped to humans when humans hunted these chimpanzees for meat and came into contact with their infected blood. Over several years, the virus slowly spread across Africa and later into other parts of the world

HIV was first identified in the United States in 1981.

It took several years for scientists to develop a test for the virus, to understand how HIV was transmitted between humans, and to determine what people could do to protect themselves.

In 2008, CDC adjusted its estimate of new HIV infections because of new technology and developed by the agency. Before this time, CDC estimated there were roughly 40,000 new HIV infections each year. New results shows there were dramatic declines in the number of new HIV infections from a peak of about 130,000 in the mid 1980s to a low of roughly 50,000 in the early 1990s.

Results also shows that new infections increased in the late 1990s, followed by a leveling off since 2000 at about 55,000 per year. In 2006, an estimated 56,300 individuals were infected with HIV.

AIDS cases began to fall dramatically in 1996, when new drugs became available. Today, more people than ever before are living with HIV/AIDS. CDC estimates that about 1 million people are living with HIV or AIDS. About one quarter of these people do not know that they are infected: not knowing puts them and others at risk.

Source: National Institutes of Health