Danny Penman has written an article in the UK-based Daily Mail discussing the international trade in monkeys destined for labs. It is an informative article and many will find it interesting. The article per se however is not what this blog is about. Rather it is about what an animal advocate says in the article. Penman:
Many scientists say experimenting on primates is essential for medical progress. Emeritus Professor David Morton, a vet and bioethicist from Birmingham University, says: ‘Sometimes you cannot use anything other than primates if you want to get good scientific data. For example, you wouldn’t have the polio vaccine if primates had not been used in research.
To the first approximation, David Morton has impeccable animal advocacy credentials.
- Member World Society for the Protection of Animals: Scientific Advisory Panel.
- Founder Member RSPCA Scientific Advisory Panel.
- Member of the Nuffield Council on Bioethics Working Party on Xenografts.
- Founder member of the British Veterinary Association’s Ethics Committee.
- Chairman of the Animal Welfare Science, Ethics & Law Veterinary Association.
- Member of the World Veterinary Association’s Animal Health and Welfare Committee.
He is also a strong advocate of the Three Rs and has been a trustee of FRAME in the UK. So his position that nonhuman primates provide good scientific data and that society would not have the polio vaccine without them seems reasonable.
But lets delve a little deeper into his position.
The claim that society would not have a polio vaccine without the use of nonhuman primates is a common one. Discuss the topic of animal-based research with virtually any vivisection activist and you will hear this stated. The real story is a bit different.
Nonhuman primates were used as predictive models for humans in the polio vaccine development and failed miserably. Paul:
There was a noticeable omission here of the word experimental in describing this work which was concerned only with poliomyelitis induced artificially in the monkey. Indeed this was a major mistake that was to dog Flexner's footsteps throughout his entire professional life-his failure to distinguish between certain aspects of experimental poliomyelitis in the monkey and the disease in man. This led him to misinterpretations, not so much in terms of pathology but of pathogenesis. It was an error with unfortunate implications that were to influence thought at the Rockefeller Institute for a generation. Eventually Flexner recognized well enough that in different species of monkeys (chimpanzees had not yet come into the picture) poliovirus behaved somewhat differently, but by this time it was too late. In 1910, and for years thereafter, his mind was set in the belief that the experimental infection simulated so exactly the disease in man that conclusions about pathogenesis could be drawn equally well from observations on either species-and he chose the monkey.” [(Paul 1971) p108]
Flexner retired as director of the Rockefeller Institute in 1935, and his death occurred some eleven years later. That was almost a decade before the final "conquest" of poliomyelitis. The experimental path he had elected to follow in later years only led him further and further away from the human disease and deeper into the woods. He had convinced himself and his colleagues that the virus was a strictly neurotropic one that entered the body by the nasal route and proceeded directly to the central nervous system. He developed with Noguchi a strange enthusiasm for "globoid bodies," which together they considered, but only for a while, as a substitute for polioviruses. He once even intimated that these bodies might be found in the human buccal and nasal mucosa. He steadfastly held out against the alimentary tract as the portal of entry. Remarkably enough, he was resistant to the idea that polioviruses are actually a family composed of several types with different antigenicity. But more than that, he held out doggedly against methods of clinical investigation which included clinical virology-approaches that eventually made possible the unraveling of the whole story. [(Paul 1971) p116-118] (Emphasis added.)
Another influential polio researcher, Draper, accepted Flexner’s mistaken views referred to above. This resulted in: “The clock had been set back about twenty five years in poliovirus research.” [(Paul 1971) p382-5]
Furthermore, what is usually left unasked about polio is this: What would have happened had monkeys never been used? This is a legitimate question in light of all the times monkey models mislead researchers. For example:
- Ignoring the gut as the source of the systemic nature of the infection and instead focusing on the nasal route.
- Nasal application of harmful treatments such as picric acid.
- Creation of MV strain implying neural tissue must be used to grow virus in vitro.
- Tissue culture was available as of 1907 yet because of the MV strain prejudices monkeys continued to be used. Since culturing the virus was the most important step leading to a vaccine this alone is damning.
- Assuming a vaccine that worked well in monkeys would do the same in humans vis-à-vis Brodie and Kolmer’s vaccine-induced paralysis and deaths.
- Consuming a vast majority of the time, money and other resources.
- Consistently believing monkey data over human data.
These are not small indiscretions.
Most of what was needed to begin work on a vaccine was present by the early 1900s. If the scientists had not been enthralled with monkey experiments, perhaps a tissue culture could have been developed sooner followed by a vaccine. We can never know, but we can speculate and we should as polio is held up as a triumph of the animal model despite the many failures, harms, and delays it caused.
Sabin recalled the history of the monkey model for polio:
Paralytic polio could be dealt with only by preventing the irreversible destruction of the large number of motor nerve cells, and the work on prevention was long delayed by the erroneous conception of the nature of the human disease based on misleading experimental models of the disease in monkeys. (Sabin)
Nonhuman primates were used successfully to grow the poliovirus. Considering that viruses had already been grown in vitro and that the reason the poliovirus was not grown was due to a mistake about the nature of neural tissue, many believe the poliovirus could have been grown in vitro as early as the 1920s. Society probably could have had a vaccine by the end of the 1920s had it not been for the reliance of nonhuman primates as predictive models for humans.
Most of what turned out to be true about poliovirus was learned from human clinical observation, human clinical studies, autopsies, and in vitro work with human tissues in the lab. Most of the blind alleys were due to monkey experiments. (I am currently working on an article about the history of the polio vaccine and animal models. The article will of course be much longer and more thorough than a blog, but the main point remains the same.)
In addition, such sweeping statements like society today would be without the polio vaccine completely ignore the fact that the vaccine was invented 60 years ago and even if it had not been invented then it probably would have been invented later even without monkeys. It is unrealistic to think the polio vaccine could not be invented today with all our technology. Granted, I would rather have had it invented in the 1950s than the 2000s but then again I would have rather it been invented in the 1920s when monkey studies originally mislead researchers and delayed the vaccine for decades. Whenever you hear such sweeping statements consider the source very carefully.
All of this gets us back to the main point I make in these blogs: animals cannot predict human response to drugs and disease. When Morton states that: “. . . you cannot use anything other than primates if you want to get good scientific data” he means data that is predictive for humans. This position is simply wrong. Why a man with the scientific credentials of David Morton would maintain such a position, I leave to the readers to decide. But it is not because he is uninformed or unintelligent or uneducated. The fact that he has been on all the above-mentioned boards and committees forces me to seriously question the motivation of those organizations as well. Could it be that some of those organizations that proclaim advocacy for animals are being disingenuous?
When you see people who have built their careers and reputations advocating the Three Rs, be very suspicious. The Three Rs are a reasonable approach for a very small percentage of animals used in science. But these instances of animal use are not what advocates for the Three Rs focus on. They focus on the issues society is most concerned about, and that involve the most money; the use of animals as predictive models for human response to drugs and disease. The Three Rs are not applicable here. Since animals simply cannot predict human response, the practice should be abandoned. Period. That is good science regardless of the ethics.
The fact that Three Rs advocates like Morton misrepresent history and claim animal models are predictive gives me reason to question whose interest they, and the organizations they represent, are really concerned about. As always, I suggest the reader follow the money.
Paul, J R. 1971. A History of Poliomyelitis. New Haven: Yale University Press.
Sabin, Albert. Testimony before the subcommittee on Hospitals and Health Care, Committee on Veterans Affair’s, House of Representatives, April 26, 1984 serial no. 98-48.