Transmission of the Human Immunodeficiency Virus

Abstract

THE likely routes of transmission of the acquired immunodeficiency syndrome (AIDS) were established before an etiologic agent was identified. The appearance of AIDS in disparate populations, connected only by probable routes of transmission, was among the initial pieces of evidence suggesting an infectious cause. First described among homosexual men in June 1981,¹ AIDS was recognized among intravenous drug users and Haitians the following year^{2 , 3} and among recipients of blood or blood products,^{4 , 5} infants born to mothers at risk,⁶ heterosexual sexual partners of patients with AIDS,⁷ and Africans⁸ by early 1983. These populations were clustered into a hierarchy of mutually exclusive . . .