TROPICAL RAINFORESTS: Disappearing Opportunities

The Origin of AIDS

June 1, 1999

The real origin of acquired immunodeficiency syndrome (AIDS) is not an experiment gone awry or a Western conspiracy against Africans, but a virus from the rainforest of West or Central Africa.

AIDS is actually not a single disease but a collection of infections and malignancies that occur as a result of infection by the human immunodeficiency virus (HIV). HIV weakens the immune system by destroying lymphocytes, a type of white blood cell that wards off infection.

There are three known HIV viruses (HIV-0, HIV-1, HIV-2), all which are classified as retroviruses of the lentivirus family. These viruses are descended from simian immunodeficiency virus (SIV) present in monkeys and apes. Presently it is still unclear how HIV-1 (the virus that most menaces man) made the species jump from SIV-infected chimpanzees to humans. One theory is that the SIV contamination of polio vaccines administered during widespread immunization campaigns in Central Africa during the late 1950s was responsible for the transfer. Another leading theory suggests that HIV originated from "natural transfers" of SIVs (through bites and scratches) from simians to humans in Central Africa. Under this theory, the relatively recent outbreak of HIV as a global epidemic can be attributed to increasing contact between forest dwellers and the outside world through urbanization, civil unrest, deforestation, immunization campaigns, and the construction of an extensive road network.

At the 7th Conference on Retroviruses and Opportunistic Infections in San Francisco, a team of researchers announced they had traced the divergence of AIDS from SIV to around 1930. The study assumed genetic changes in the virus occur at a constant rate. Should this dating prove correct, it would undermine OPV/AIDS hypothesis.

Continued: Extinction

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