Portal:Viruses/Selected article/14
AIDS is a progressive immunodeficiency disease first recognised in 1981, caused by infection with human immunodeficiency virus (HIV). Initial infection is sometimes associated with a brief influenza-like illness, followed by a period of 3–20 years without symptoms during which the immune system deteriorates. The individual becomes highly susceptible to common infections such as tuberculosis, as well as opportunistic infections, such as Pneumocystis pneumonia, and tumours, such as Kaposi's sarcoma and lymphoma. Severe weight loss is also a feature of AIDS. Without treatment, the average survival time after infection is around 9–11 years, depending on the HIV subtype.
HIV/AIDS is a global pandemic. As of 2018, nearly 38 million people worldwide are estimated to be infected with HIV, with 1.8 million new infections occurring each year. AIDS has caused around 32 million deaths. The major routes of transmission are unsafe heterosexual or male/male sex, contaminated needles and blood transfusions, and from mother to child, either at birth or via breastfeeding. Combination antiretroviral therapy does not eliminate the virus, but delays progression to AIDS and can lead to a near-normal life expectancy. Drugs to prevent infection are now available, but there is no effective HIV vaccine.