The global epidemic of AIDS.

Recent changes in sexual habits have likely contributed to the emergence of a new sexually transmissible agent, acquired immune deficiency syndrome (AIDS) virus. This virus may have been present in central Africa as early as 1959; however, frequent infection did not produce an epidemic until the late 1970's. Migration of Africans from rural to urban areas may have contributed to the transmission of AIDS virus. An estimated 1.7 million Americans and 5,000,000 Africans are infected. An incubation period of five years +/- 36 months to onset of disease is estimated. Development of AIDS during a three-year period after detection of AIDS virus antibodies has occurred in 30% of homosexual males in Manhattan and 10% of infected men in Denmark. Conservatively, in excess of 20% of seropositive will likely develop AIDS. Although modification of sexual behavior is recommended, those who will develop AIDS in the near future are already infected. Public health workers ought to be preparing for additional pandemics of infectious diseases which may arise from changing cultural habits.