In an exclusive interview here, Dr Jacques Pépin cuts through some of the myths surrounding the AIDS virus.
How long has it taken you to research and write The Origins of AIDS?
About five years ago, I visited the tropical medicine institute in Marseilles to gather information about sleeping sickness in a specific part of the southwest of the Central African Republic. On my first day there, to my amazement, I suddenly understood, while looking at the health systems annual reports, the scope of the colonial-era public health interventions that required the administration of massive amounts of IV drugs over the whole of central Africa and throughout several decades. I went back a few months later and it was after this second visit that I decided to write this book. The additional research (on the many other elements of the story) and the writing required about 4 years, and one more year to go through the various stages of the publication process.
What was the greatest challenge you faced in writing The Origins of AIDS?
I wanted the book to be accessible to a large audience, what editors call ‘the intelligent layperson’. On the other hand, I wanted this history of the emergence of HIV/AIDS to be coherent and comprehensive. So some sections of the book (I would say about 15%) will be more difficult to digest for the general public, while the rest, which is mainly of a historical nature, will be easier. I hope to have achieved a reasonable compromise.
The first cases of AIDS were diagnosed in June 1981 in Los Angeles. But you’ve traced the AIDS virus back to this single bush hunter in Central Africa in 1921. How did you connect the dots between then and now?
In many chapters of the book I presented original research (historical and epidemiological) which I have conducted. In others, I summarized and assembled the many pieces in the puzzle which have been delineated by other researchers, published in dozens of 3000-word articles in scientific journals, digested these publications to present them in a way that can be understood by non-specialists, and finally assembled these into a coherent story. It has been known for 12 years that the source of HIV-1 is the Pan troglodytes troglodytes chimpanzee of central Africa, through the work of molecular biologists under the leadership of Dr Beatrice Hahn. The timing of the most recent common ancestor of all HIV-1 strains was estimated a few years ago by a group led by Dr Michael Worobey. But I also spent a lot of time in colonial archives and in European libraries, to document for instance the urbanisation of central Africa, how the colonizer’s policies led to urban prostitution, how this evolved over time in a way that first merely allowed the persistence of HIV-1, and later its expansion. I also spent a lot of time understanding and describing the public health interventions which certainly played a major role in the early emergence of HIV-1, and I conducted epidemiological studies which documented that several blood-borne viruses were indeed transmitted during several medical interventions in different parts of Africa.
From chimpanzee to man… It is understood that the Pan troglodytes troglodytes chimpanzee is the source of HIV-1. But why only that one species of chimpanzee? And how was the disease transmitted to humans?
The first question remains a mystery. On the other side of the Congo River lives another subspecies of chimpanzee, Pan troglodytes schweinfurthii, a substantial fraction of which are infected with their own version of the simian virus SIVcpz. The social and medical conditions that facilitated the emergence of HIV-1 west of the Congo were also present east of the Congo. It may be that there were fewer opportunities for the initial transmission of the virus from chimp to man. Or perhaps the P.t. schweinfurthii virus differs from its P.t. troglodytes counterpart in a way that makes it less transmissible to humans, or between humans.
The initial transmission of the Pan troglodytes troglodytes virus to a human, who became the true ‘patient zero’, certainly occurred through the manipulation of chimpanzee meat. Either a hunter got injured with his knife when he cut out the ape to bring the carcass back to the village so that the chimp’s blood became in contact with his own blood, or the same type of accident occurred during the actual cooking of chimpanzee meat. HIV-1 can be transmitted this way – we know this from the numerous healthcare workers who became infected while sustaining an injury with a needle just used on a HIV-infected patient. Three other potential modes of transmission from chimp to man, which have been proposed over the years, can now be rejected, since there is nothing to sustain these other hypotheses.
In The Origins of AIDS, you argue that far from being spread through sexual activity alone, human intervention in the form of colonisation, urbanisation and well-intentioned medical care has facilitated the spread of the virus. To what degree are we accountable?
The two processes that drove the early emergence of HIV-1, urban prostitution (sexual transmission) and medical interventions (iatrogenic transmission), were directly linked to the European colonisation of central Africa. I think the combination of both processes was essential to the development of the pandemic. The absence of these factors prior to the 20th century probably explains why HIV-1 did not spread sooner in human populations. SIVcpz has been present in chimpanzees for at least several hundred years, and hunters or hunters’ wives certainly got infected once in a while. These all became epidemiological dead ends, until the above-mentioned processes appeared.
It is hard to say what would have happened without colonization: large cities would have developed anyway, but perhaps without the gender imbalance that drove colonial-era prostitution. Local health systems would have appeared, but perhaps only after the risk of transmitting blood-borne viruses through injections had been recognized. Who knows?
You have personal experience of working in central Africa, both in training and as a clinical researcher. How has this experience coloured your research?
I got really interested in that topic when I belatedly understood that there was a link between the treatment of sleeping sickness and HIV-2 infection in Guinea-Bissau. If I had not worked on these two very different diseases 20-30 years ago, I would never have understood that transmission of viruses during healthcare played a major role in the emergence of HIV-1 and HIV-2, in two different parts of Africa, almost simultaneously. Having worked in the Congo and having married a Congolese, I have read a lot about the colonial and post-colonial history of that part of the world. And being francophone was essential in deciphering the archives of these colonies.
And finally, what’s next?
Perhaps I will translate The Origins of AIDS into French. And later on, I might try to write another book on a totally different topic, which should keep me busy for the next five years….
The Origins of AIDS is an essential new perspective on HIV/AIDS and on the lessons that must be learnt if we are to avoid provoking another pandemic in the future.
Jacques Pépin is the author of ‘The Origins of AIDS’ (out now). He is Professor and Head of the Infectious Diseases Division, Department of Microbiology and Infectious Diseases at the University of Sherbrooke, Canada, where he is also Director of the Centre for International Health. He has conducted research on infectious diseases in sixteen African countries.