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Epidemiology of HIV infection / AIDS
Last reviewed: 06.07.2025
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HIV infection is found on all continents and in almost all countries where a systematic search for patients is conducted. According to WHO, about 50 million people live with HIV infection. More than 2 million people with HIV infection are identified annually.
The age structure of those who fell ill, and especially those infected, has not been precisely determined. According to generalized data, the proportion of children among those who fell ill reaches 10% or more.
The reservoir and source of infection can only be an infected person, a sick person or a virus carrier. The virus in the human body is found in the blood and various organs. The virus is especially often found in lymphocytes, which gives reason to consider the lymphocyte as the natural place of residence of HIV. The virus is excreted from the body mainly with sperm and menstrual blood. There is evidence of the presence of the virus in saliva, tear fluid and breast milk. However, the concentration of the virus in these biological fluids is low.
Children become infected transplacentally and through blood transfusions. Intrauterine transmission of infection begins to be detected from the 15th week of gestation, and HIV, unlike other retroviruses, is not transmitted to offspring as an insertion into the genome, but penetrates the fetus directly with the mother's blood. A child can also become infected during passage through the birth canal. As a result, up to 36% of children born to infected mothers become infected with HIV.
Theoretically, infection can occur through close contact through microtraumas, cuts, bites, if virus-containing material (blood, saliva, sperm) gets on damaged skin or mucous membranes. HIV infection is possible during organ and tissue transplantation, as well as during artificial insemination. Transmission of HIV by airborne droplets, through saliva, blood-sucking insects has not been proven and is unlikely.
Susceptibility to HIV has not been precisely established. There is reason to believe that it is extremely high or even universal.
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