"The Hollywooding of Science". Beatrice Hahn's latest SIV sequences from Cameroonian chimps: an alternative interpretation
Updated 5 August, 2006
If you're new to these issues, read this first.
a) The latest paper by Beatrice Hahn's team (B. F. Keele, B. H. Hahn et al: "Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1") [Reference 1] features claims that they have discovered the source of pandemic HIV-1, the "AIDS virus".
b) However, on the basis of the evidence presented, this claim is unsafe. In fact, more than that, it represents a rash over-extrapolation.
c) The reasons for rejecting Hahn's claim include the following: (i) less than 1 in 200 of the chimp troops in this part of Africa have thus far been sampled for SIV; (ii) in reality, the new chimp viruses she has found fall far short of being "dead ringers" for pandemic HIV-1, as has been claimed; (iii) there are close physical and biomedical similarities between Pan troglodytes troglodytes (Ptt) chimps and Pan troglodytes schweinfurthii (Pts) chimps, which some believe should be regrouped into a single subspecies; (iv) members of some groups of Ptt cluster genetically with Pts, and vice versa; (v) despite their claims to the contrary, Hahn and co-authors have not established that Ptt (rather than Pts) represents the reservoir of pandemic HIV-1; (vi) furthermore, the closest primate virus ancestor to pandemic HIV-1 may have existed in a chimp troop that is now extinct.
d) The true reason why it is so important to Hahn's group to establish the Pan troglodytes troglodytes subspecies of chimpanzee as the reservoir of pandemic HIV-1 is that they believe that this refutes the OPV/AIDS theory, which proposes that AIDS began as a result of chimpanzee experiments conducted in Stanleyville, Belgian Congo, in the late 1950s.
e) However, their latest findings do not disprove the OPV/AIDS theory. For a long time, there has been substantial anecdotal and circumstantial evidence that at least some Ptt chimps were present at Stanleyville and/or the nearby chimp camp at Lindi. But a recently-unearthed Belgian article from 1965 proves that the Stanleyville doctors were working with at least one Ptt chimp in early 1960, and perhaps in 1959. Co-caging and group caging were routine at the holding centres at both Lindi and Stanleyville, meaning that viruses could have spread from this Ptt (or similar animals) to other primates (Pts and bonobos) housed in these centres.
f) Furthermore, it is far easier to postulate Ptt chimps, including chimps from south-eastern Cameroon, ending up in the huge holding centres at Lindi and Stanleyville than it is to postulate a human infectee moving from Cameroon to Leopoldville, allowing AIDS to spawn there - and only there.
g) It is also worth emphasising that because of recombination between SIV strains, the origin of pandemic HIV-1 does not automatically require the involvement of the closest viral ancestor genetically. [See below for further details.]
h) There are multiple problems with the latest Hahn/Sharp scenario of how the AIDS pandemic might have started in Leopoldville (over 600 miles by river from her alleged chimpanzee "source"). By contrast, the OPV/AIDS hypothesis is inconvenienced by none of these.
i) The discovery that Ptt were used in the Stanleyville experiments has more significance for the origin of AIDS than Hahn's latest data from Cameroon. Once again, the claims by Hahn and her buddies that "the OPV theory has been laid to rest" are revealed as empty bluster.