The Origins of AIDS (7 page)

Oral poliovirus vaccines (OPV) distributed in the 1950s and early 1960s were massively contaminated with a simian virus
(simian vacuolating virus 40), which originated from the macaque cells used to grow the vaccinal virus. Fortunately, this virus was not pathogenic for humans. In an article published in
Rolling Stone
in 1992, journalist
Tom Curtis proposed the theory that HIV-1 came from the contamination of OPV with SIV from African green monkeys. Of course, it was later shown that African green monkeys were not the source of HIV-1, as their own SIVs were too different from HIV-1.
Then in 1999, Edward Hooper published a book entitled
The river. A journey back to the source of HIV and AIDS
, which focused on the theory that chimpanzee cells had been used to produce an experimental oral polio vaccine called CHAT, developed by
Hilary Koprowski at the Wistar Institute in Philadelphia.
Koprowski had collaborated with Belgian scientists from the Stanleyville public health laboratory in the Belgian Congo. Clinical trials of the CHAT vaccine were conducted between 1957 and 1960 in the vicinity of Stanleyville, in the capital Léopoldville, as well as in the
Ruzizi valley of Ruanda–Urundi. Eventually, the Koprowski vaccine proved inferior to the other OPV developed by his competitor
Albert Sabin, and CHAT was never commercialised.
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The Stanleyville laboratory set up a colony of chimpanzees (presumably, all
P.t. schweinfurthii
or
Pan paniscus
)
nearby, at a place called
Camp Lindi, primarily to verify experimentally not just the efficacy but also the neurological virulence of the CHAT vaccine. Experimental oral polio vaccines were based on live viruses which had been empirically
attenuated through repeated passages over various cell cultures, and scientists were worried that these viruses could eventually regain their original virulence, in which case the vaccine would cause the disease rather than prevent it
. Camp Lindi chimps were given the CHAT vaccine, then the wild polio virus, and monitored clinically for neurological deficits. Others were sacrificed for their spinal cord to be examined after intraspinal injection of the CHAT virus. In addition, about thirty chimpanzees were used for
hepatitis research, in an attempt to identify the agents of viral hepatitis through inoculation of stool suspensions from human patients.

The main theory in
The river
was that the Stanleyville laboratory had supplied the Wistar Institute with chimpanzee tissues obtained from sacrificed animals, which had then been used in Philadelphia to produce the CHAT vaccine so that SIV
_cpz
had been introduced into some vaccine lots, which were then sent back to the Congo where their oral administration in the late 1950s started the pandemic. A number of elements described in the book itself made this theory implausible, most importantly the fact that
Koprowski had conducted very large trials of the same CHAT vaccine in his native
Poland, where HIV-1 did not emerge. It would have been an extraordinary coincidence for SIV
_cpz
-contaminated vaccines to be re-exported from Philadelphia only to the very country where, allegedly, the SIV
_cpz
-infected chimpanzee tissues had been obtained. Then Hooper changed his hypothesis somewhat, and suggested that the Stanleyville laboratory had produced batches of the vaccine locally, using cells from locally procured chimpanzees, which led to contamination with SIV
_cpz
in Stanleyville rather than in Philadelphia.

Many circumstantial elements argued against either version of the hypothesis. There is no documentary evidence that chimpanzee cells were ever used, anywhere in the world, to produce OPV. Scientists had easy access to small
monkeys of the
Macaca
genus, which were abundant in Asia, cheaper and easier to handle than chimpanzees, raised fewer ethical issues and worked well in cell culture systems. In 1955, up to 200,000 rhesus monkeys were imported into the US for medical research. Furthermore, as noted by the late Dr
Paul Osterrieth, a scientist who worked at the Stanleyville laboratory for a few years, it was technically impossible for this rather basic facility to produce any kind of novel viral vaccine. The laboratory just did not have the human and material resources for such an endeavour. The annual reports of the
Stanleyville laboratory for the crucial years never mentioned any local production of OPV, something that, had they achieved it, the laboratory workers would certainly have been proud of. Neither did the reports of the colony‘s health system mention any local production of OPV – while the same reports provided much information about other
vaccines produced by the network of public health laboratories of the Belgian Congo. Hooper seems to have confused
conditionnement
, which meant local dilution of concentrated frozen vaccine stock or its distribution from a large container to smaller containers, with local production or amplification of the vaccine strain.
^35
–
37

Nevertheless, to test this hypothesis once and for all, old vials containing the CHAT vaccine, which had been kept frozen for decades, were located. Some came from the Wistar Institute, where CHAT had been developed and produced, and conspiracy theorists could argue that this institution had a vested interest in supplying vials which they already knew were not contaminated with HIV-1
. But other CHAT vials were fished out of freezers at the
CDC in
Atlanta and at Britain‘s National Institute for
Biological Standards and Control (NIBSC). Some vials contained the very batches (10A-11 and 13) that had been used in the Belgian colonies. Samples were tested by several institutions, including the NIBSC, the
Institut Pasteur, the
Max Planck Institute, the
Karolinska Institute, the
New York University School of Medicine and
Roche Molecular Systems. All reached the same conclusions: there was no HIV or SIV nucleic acids in these vials; there was no chimpanzee DNA, only DNA from rhesus (
Macaca mulatta
) or cynomolgus (
Macaca fascicularis
) monkeys and, in one batch which had been grown on human diploid cells,
Homo sapiens
DNA; and there was poliovirus, which meant that there had not been extensive degradation of viral nucleic acids over the very long storage period.
^38
–
40

Furthermore, 131 faecal samples were collected from chimps in the forested areas around Kisangani (ex-Stanleyville), where the laboratory and chimpanzee colony had been located: only one was SIV-positive. This virus, obtained from a
P.t. schweinfurthii
, was called SIV
_cpz-DRC1
. In
phylogenetic trees, it was close to the
P.t. schweinfurthii
viruses obtained from
Uganda and
Tanzania and with Noah‘s SIV
_cpz-ant
, and clearly distinct from all
P.t. troglodytes
SIVs
.
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Therefore, there is no evidence that chimpanzee cells were used in the Stanleyville laboratory to prepare batches of OPV vaccines, or that any OPV was produced there. And even if chimpanzee cells had been used in
Stanleyville, they could not have contained the
P.t. troglodytes
SIV
_cpz
that triggered the pandemic
. There is no evidence either of any retrovirus having been present in the old batches of CHAT available for testing. Furthermore, even when taking into account the margin of error on these estimates, SIV
_cpz
emerged in human populations at least twenty-five years before the CHAT trials. This theory can be firmly rejected
.

Because of their similarity to humans, chimpanzees have been used for almost a century as animal models of many infectious diseases, to prove that a putative pathogen is the cause of a given disease, to evaluate new vaccines, etc. In the course of these experiments, chimpanzees have been injected with various amounts of human blood or other types of human specimens, containing a wide diversity of infectious agents: viruses (HIV-1 of course, poliomyelitis virus, hepatitis B virus (HBV), hepatitis C virus (HCV) and yellow fever virus), prions (proteins causing kuru, Creutzfeldt-Jakob disease and scrapie), bacteria (the aetiological agents of tuberculosis, leprosy, gonorrhoea and trachoma) and parasites (causing malaria and the Guinea worm). There was even a chimpanzee model of alcoholism and addiction to narcotics!

However, it is rather extraordinary that, on several occasions, the reverse was done: the IV injections of chimpanzee blood in humans. The first such experiment was performed in
Sierra Leone by Donald Blacklock and Saul Adler, who injected two Europeans (presumably, themselves) subcutaneously (SC) and intravenously with small quantities of blood from a chimpanzee infected with malaria parasites. They did not develop malaria. We do not know what happened next but they certainly got worried when the donor chimpanzee died a few days later, with the
autopsy showing a disseminated
Strongyloides
infection, with this intestinal worm being present in the chimp‘s bloodstream! Shortly thereafter, at the
Institut Pasteur in Paris, a man was injected IV with 40 cc of chimpanzee blood as part of a comparative study of blood groups of chimpanzees and humans. The volunteer apparently tolerated the procedure well. With great foresight, the Pasteur scientist noted that such experiments should be avoided in the future, ‘to keep off potentially transmitting to humans hitherto unknown infectious pathogens of chimpanzees‘!
^42
–
45

This advice seems to have fallen on deaf ears. Renowned parasitologist Jér
me Rodhain, director of the Tropical Medicine Institute in Brussels and then in Antwerp, studied whether malaria parasites of primates were transmissible to man. As a secondary interest, or perhaps as a moral justification, he also investigated whether fever induced by malaria could have a beneficial effect on patients with late-stage
syphilis. Such work would be unthinkable today but in those days there were no ethics committees and each scientist could decide whether an experiment was morally acceptable. Similar investigations were conducted in other parts of the world, especially India, with inoculation to humans of blood obtained from Asian apes and monkeys.
⁴⁶

Rodhain carried out a series of experiments in which chimpanzee blood (5–10 cc) was injected IV in humans, most of them patients with syphilitic dementia. The chimpanzees (Thomas, Suzanne, Simone . . .) originated from the Belgian Congo; although Rodhain alluded to them as
P.t. verus
, in retrospect they were probably
P.t. schweinfurthii
. Between 1938 and 1940, Rodhain injected chimpanzee blood to twenty-six patients. He did prove that some of these malaria parasites were infectious to humans, and that the parasite named by others
Plasmodium rodhaini
, in his honour, was in fact
Plasmodium malariae
. We should give him a lot of credit for being humble since he himself killed the chance of his name going down in history as the name of a species. Rodhain conducted similar experimentations with other species of malaria parasites, most notably
Plasmodium reichenowi
, a parasite of chimpanzees and gorillas. In 1954–5, he injected chimpanzee blood in four more psychiatric patients, and managed to transmit
Plasmodium schwetzi
.
^47
–
52

These experiments were done in hospitals in Antwerp and clearly could not have led to the emergence of HIV-1 in Africa. Furthermore, as the apes originated from the Belgian Congo, they were all presumably
Pan troglodytes schweinfurthii
(Rodhain would not have confused
P.t. verus
with
Pan paniscus
, the other ape potentially available from his Belgian collaborators). It seems unlikely that other scientists carried out similar experiments for malaria research, since Rodhain would have mentioned this in the detailed reviews of the subject that he wrote in the discussion section of his own papers. Of course, one could hypothesise that similar experiments were carried out in the nascent research institutions in Africa and the results never disseminated, but this would be pure speculation. There is no evidence of similar experiments being
conducted in the Léopoldville research laboratory, where Rodhain had worked during the early part of his career and which he continued to visit intermittently from his academic posts in
Belgium
.

At the
Institut Pasteur in Paris,
Auguste Pettit worked for sixteen years on developing a therapeutic serum containing high titers of antibodies against the
poliomyelitis virus, to be given to patients with this disease. As it was difficult to obtain large enough quantities of
serum from human cases recuperating from polio, he produced animal sera, which were then used on humans. Antipoliomyelitis serum was prepared from horses, monkeys and chimpanzees, and then administered to at least eighty patients. Two chimpanzees were used for this purpose; the first one was bled to death and the second was bled repeatedly over a two-and-a-half-year period. They were
P.t. verus
chimps from
Guinea, and the patients were in France not Africa. So once again, this could not have led to the emergence of HIV-1.
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