AIDS is the ultimate stage of infection with the human immunodeficiency virus (HIV 1 and HIV 2). The word AIDS is the abbreviation for Acquired Immunodeficiency Syndrome.
The AIDS virus (HIV) enters the body sexually, bloodstream or is transmitted from mother to child. This virus will then invade certain cells of the body’s immune system: CD4 T cells, which play a fundamental role in the body’s defense against microbes.
HIV develops and multiplies inside these cells, causing their destruction. The destruction of CD4 T cells leads to a deterioration of the immune system that can no longer fulfill its role: fight against infections.
Infections associated with severe immunodeficiency are termed “opportunistic infections” because they develop because of the inability of the immune system to control their development.
HIV also infects other cells: macrophages, certain nerve or muscle cells …
The term AIDS applies to the most advanced stages of HIV infection
Defined by the occurrence of one or more of twenty opportunistic infections or HIV-related cancers.
Among bacterial infections, the most common is tuberculosis, which may be due to recent contamination or reactivation of an old disease.
For viruses, it is usually reactivation of the chickenpox and shingles virus, for the parasites, the most often involved are Toxoplasma gondii (responsible for toxoplasmosis), Pneumocystis carinii (causing infections respiratory) and digestive parasites.
Finally, some people may be suffering from cancer: Kaposi’s sarcoma (linked to an infection with the HHV8 virus) or lymphoma by multiplication of white blood cell stem cells.
According to estimates by WHO and UNAIDS, 33.4 million people were living with HIV at the end of 2008.
That same year, nearly 2.7 million people were infected and 2 million died of AIDS, including 280,000 children. Two-thirds of HIV infections affect sub-Saharan Africa.