HIV (human immunodeficiency virus) infection has now spread to every country in the world. Approximately 40 million people are currently living with HIV infection, and an estimated 25 million have died from this disease. The HIV virus has been particularly devastating in Africa, but infection rates in other countries remain high. In the United States, approximately 1 million people are currently infected. Globally, 85% of HIV transmission is heterosexual. In the United States, approximately one-third of new diagnoses appear to be related to heterosexual transmission. Male-to-male sexual contact still accounts for approximately half of new diagnoses in the U.S. Intravenous drug use contributes to the remaining cases. The diagnosis may occur years after infection, there is a higher proportion of recent infections due to heterosexual transmission. Infections in women are increasing. Worldwide, 42% of people with HIV are women. In the United States, approximately 25% of new diagnoses are in women, and the proportion is rising. New HIV infections in U.S. children have fallen dramatically, with only 28 cases reported in 2007.