Abstract

PIP: This update on world prevalence of HIV infections and patterns of transmission begins with definitions of AIDS, and an evaluation of efficiency of reporting, and ends with tentative projections and global impact of the pandemic. In developed countries the CDC/WHO clinical and serological definition of AIDS as formulated in 1985 and modified in 1987 is used, but in rural Africa the WHO clinical definition of AIDS is appropriate. AIDS reporting has improved, and is considered 80% complete from the U.S. Reporting is variable among some European and Latin American countries, and is only preliminary in Eastern Europe, Middle East, Asia and the Pacific. Estimates of 10-20% reporting in Africa is given. About 250,000 cases are probably ongoing. ELISA tests are now considered very accurate. Global transmission patterns fall into 3 classes: I. homosexual and bisexual men, iv drug users, their partners, with a male to female ratio of 10-15:1, in industrialized countries. Here overall prevalence is 1%, but may be as high as 50% susceptible groups. Pattern II. heterosexuals, sex ratio 1:1, common perinatal transmission, significant transmission by syringes and blood products, in Central and Eastern Africa and parts of the Caribbean and Latin America. Pattern III. both homosexuals and heterosexuals, infected after mid-1980s, most cases transmitted by foreign travellers, some by imported blood products, in Eastern Europe, North Africa, the Middle East, Asia and the Pacific Islands excluding Australia and New Zealand. WHO estimates that up to 10 million people are already infected with HIV, and that by 1991 1 million will develop AIDS. The average incubation time is 8-9 years. The majority of cases will appear within 4-5 years. Since most cases are adults aged 20-49 years, and many are urban, more educated adults, economic and political destabilization may be possible in some areas.