Absence of antibodies to the human immunodeficiency virus in sera from Africa prior to 1975.

Three different assays for detection of antibodies to the human immunodeficiency virus (HIV) were conducted on 677 sera obtained from 1964 to 1975 from male and female children and adults in Uganda and other countries in Africa. Several sera were collected from individuals with Kaposi sarcoma. No evidence of antibodies to the virus was noted up to 1975. These results strongly suggest that the emergence of HIV in Africa occurred relatively recently. Further studies are required to determine the geographic origin of the acquired immunodeficiency syndrome virus.