Human immunodeficiency virus (HIV) is the virus that is
responsible for causing acquired immune deficiency syndrome
(AIDS). The virus destroys or impairs cells of the immune system
and progressively destroys the body's ability to fight
infections and certain cancers. In adults and adolescents, HIV
is most commonly spread by sexual contact with an infected
partner. Before routine screening of blood products began in
1985, a small group of children were infected with the virus by
contaminated blood products. Currently, nearly all HIV
infections in children under the age of 13 are from vertical
transmission, which means the virus is passed to the child when
they are in their mother's womb or as they pass through the
birth canal. The virus has also been detected in breast milk,
and can be spread by breastfeeding. It should be noted that not
every child born to an HIV-infected mother will acquire the
virus. Without treatment, a woman with human immunodeficiency
virus (HIV) has a one in four chance of infecting her