ABC of AIDS. Development of the epidemic.

Abstract

The 1st recognized cases of the acquired immunodeficiency syndrome (AIDS) occurred in the summer of 1981 in America. HIV has been isolated from semen cervical secretions lymphocytes cell free plasma cerebrospinal fluid tears saliva urine and breast milk. Particularly infectious are semen blood and possibly cervical secretions. The commonest mode of transmission of the virus is by sexual intercourse. Other methods of transmission are through the receipt of infected blood or blood products and donated organs and semen and through the sharing or reuse of contaminated needles by injecting drug abusers or for therapeutic procedures and from mother to child. There is no well documented evidence that the virus is spread by saliva. It is not spread by casual or social contact. By March 1987 31526 adult cases of AIDS had been reported in the US plus an additional 456 pediatric cases. There is a wide geographical variation. New York for example has a rate of 991/million. The US as a whole has a rate of 140/million. In the US and the UK the 1st wave of the epidemic occurred in homosexual men the next and current wave is among intravenous drug abusers and after this it might affect the heterosexual population. Transmission into the heterosexual population will occur through bisexual men intravenous drug abusers and prostitutes. In Africa strong evidence shows that HIV is spread mainly by heterosexual intercourse. The advent of an effective antibody test in 1984 has allowed for a clearer understanding of the changing prevalence and natural history of HIV infection. Surveys show that the proportion of individuals infected must be high before cases of AIDS start to become apparent. AIDS is the most major public health problem in the world this century.