[AIDS in Africa].

While AIDS (Acquired Immunodeficiency Syndrome) certainly represents a worldwide health problem, the attention of many researchers and epidemiologists, besides the WHO itself, has recently focused on Africa for the following reasons: 1) The etiologic agent of AIDS, the Human Immunodeficiency Virus (HIV) (previously named HTLV-III or LAV) is likely to have originated in Africa. Solid evidence has been accumulated that antibodies against HIV were present in African sera collected in the early 1960s. In the same period widespread infection by viruses strictly related to HIV has been documented in primates living in tropical Africa. A second type of HIV (now named HIV-2 and previously known as HTLV-IV or LAV-2) which is responsible for a milder AIDS-related disease, has been subsequently identified in West African inhabitants with its own simian correlate. Although epidemiological evidence for the presence of AIDS in Africa in these early periods is scanty, sporadic cases have retrospectively been identified. 2) Up to 1986, AIDS epidemiology in Africa has been hampered by inconsistency of demographic data, inadequacy of public health services and difficulty of obtaining the necessary laboratory evidence. The few data available (Zaire, Rwanda), suggests an annual incidence in 1983 of 170-800 per million, comparable to higher U.S. and European rates. There is no evidence, however, that African epidemy precedes that of the U.S., for which there is no explanation at present. On the other hand, recent data indicate an alarming acceleration of the African epidemy, that spreads well beyond the risk groups which have been recognized in Western countries. 3) Prevalent infection routes in Africa are not entirely overlapping with Western countries'. Rather than homosexual intercourse (U.S.) and syringe sharing by drug abusers (Italy), most African cases seem to be transmitted by heterosexual promiscuous contacts and, to a lesser extent, by blood derivates and recycled syringes. Insects and tribal rituals have been also suspected as vehicles of infection in Africa; widespread prostitution and inadequate health facilities certainly are. As a consequence, transplacental infection appear much more common than in the West. 4) Clinical aspects of AIDS progression in Africa appear linked to the different spectrum of opportunistic agents present on the continent and to the general hygienic and social conditions prevailing among its people. Rather than generalized lymphoadenopathies and Pneumocystes Carini pneumonia, diarrhoea and extreme weight loss ("Slim disease") represent the most common clinical pattern.