Origins of HIV and the AIDS Epidemic

September 11-12, 2000, The Royal Society, London, United Kingdom

Jonathan Weber, FRCP, FRCPath, FmedSci, Keith Alcorn, Medical Writer

Disclosures
In This Article

In Search of HIV's Ancestral Hearth

If SIV crossed the species barrier in several places and then began to spread slowly, where are the most likely places for this to have occurred?

A review of subtype diversity by Martine Peeters found that the greatest diversity -- indicative of the greatest duration of opportunities for recombination with other viruses -- is found in the vicinity of Kinshasa, and that Congo generally shows the greatest degree of subtype diversity of any region in Africa. But does this necessarily make Congo the ancestral hearth of HIV or just the crossroads at which a number of viruses were able to come together?

Francine McCutchan reviewed current knowledge about circulating recombinant forms of HIV and the evidence for recombination events in the ancestry of different HIV subtypes. East and South Africa have a low level of recombinants, but in West and Central Africa the dominant subtypes, including recombinant forms and the "pure" subtypes, show evidence of common recombinant break points that indicate a common recombinant ancestor. This in turn would indicate a greater degree of opportunities for recombination events, both in terms of duration of infection in the region and rates of partner change. Whether the higher frequency of recombinants is a marker for the length of time HIV-1 been circulating in the region is debatable.

As sequence information accumulates and phylogenetic dating becomes more sophisticated, it may become easier to answer, but at present any assertions on the location of first transfer are highly speculative.

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