Perspectives On Medical Research
Volume 5, 1995
Aping Science
A Critical Analysis of Research at the Yerkes
Regional Primate Research Center
Primate Research Risks
1. Viral Epidemics
The risk of initiating devastating epidemics by inadvertently exposing humans
to lethal nonhuman primate viruses during experimental procedures has been
suggested by the controversy regarding the origin of AIDS. The evidence suggesting
that the ADS epidemic started with an oral polio vaccine contaminated with
HIV1,2 has generated heated debate3 and even a lawsuit
from the scientist who developed the vaccine.4,5 This contamination
theory has been explored further by B. Elswood and R. Stricker, who have proposed
several mechanisms by which polio vaccines could have become contaminated with
HIV.6 Although their theory has not gained wide acceptance, the
important point from a public health perspective is that medical use of primates
could have started the AIDS epidemic and might start yet other epidemics in
the future.
The exposure through polio vaccination of 10-30 million Americans and hundred of millions of others to a simian virus called SV407 illustrates how vaccines from monkey cells can expose people to potentially dangerous viruses. SV40 can transform human cells in vitro,7 and it has been implicated in several human tumors.8 SV40 has been isolated from the brains of two patients with a slowly progressive viral disease called progressive multifocal leukoencephalopathy9 and from a metastatic melanoma,10 and SV40 antigens have been found in pediatric and adult brain tumors.11 People who have received SV40-contaminated vaccines have a greater incidence of brain tumors,12 and SV40 has also been implicated in bladder, oromaxillofacial, and parotid gland tumors.6 The Collaborative Perinatal Project13 impressively showed that the risk of brain tumors of children whose mothers had received the Salk polio vaccine was 13 times greater than those whose mothers had not (p < 0.01).14 Interestingly, none of the mothers whose children had brain tumors showed evidence of SV40 infection in their blood,14 suggesting that some other, yet unidentified virus was responsible.15
Although it is uncertain how AIDS started, a likely explanation is that an HTV-like virus was somehow transmitted from chimpanzees to humans,16 perhaps during capture for biomedical research. A virus isolated from a chimpanzee captured in Gabon resembles HIV much more than any of the monkey SIV isolates.17 Brandon Reines has proposed that atomic bomb tests off Africa’s coast may have caused DNA damage to primates, one effect of which could have been the release of viruses contained within their DNA that, previously, had not caused disease and had been inherited from one generation to the next. Reines notes that two immunodeficiency epidemics have occurred nearly simultaneously in the latter half of the 20th century--HTV-l likely from chimpanzees and HIV-2 likely from monkeys--suggesting an external trigger for these novel diseases.18
Similar to AIDS, it appears that hepatitis B originated from human exposure
to chimpanzees, who often carry hepatitis B asymptomatically.’9
Other nonhuman primate viruses, perhaps even more lethal than HIV, pose
substantial threats to humans.20-23 The most lethal viruses
have been the “B viruses” of the herpes family, which were
responsible for two “Ebola virus” outbreaks in central
Africa that had mortality rates up to 90%--killing hundreds of people.23 B
viruses have infected about 25 people associated with primate research
activities, resulting in a mortality rate of 67-75%.24-26 There
may be many more unrecognized deadly viruses hidden in nonhuman primate
DNA that could cause devastating worldwide epidemics.23 Indeed,
today’s ease of international travel greatly facilitates spread
of infectious diseases.
2. Social Risks
Monkeys and apes can serve as powerful metaphors for humans because many people
see them as “almost human.”27 Supposedly devoid of
culture, monkeys and apes presumably reflect humans in their “natural” state.28 Of
course, this perspective fails to appreciate monkeys’ and apes’ complex
social relations and rich cultures29-31 and it ignores millions
of years of divergent physical and cultural evolution. Nevertheless, nonhuman
primate research captures the public’s attention because analogies between
monkeys and humans are dramatic and therefore compelling. As sociologist Donna
Haraway has pointed out:
The commercial and scientific traffic in monkeys and apes is a traffic in meanings, as well as in animal lives. The sciences that tie monkeys, apes and people together in a Primate Order are built through disciplined practices deeply enmeshed in narrative, politics, myths, economics, and technical possibilities. The women and men who have contributed to primate studies have carried with them the marks of their own histories and cultures. These marks are written into the texts of the lives of monkeys and apes, but often in subtle and unexpected ways. People who study other primates are advocates of contending scientific discourses, and they are accountable to many kinds of audiences and patrons.32
Haraway has also noted how conveniently primate researchers have “found” correlates in primate populations for racist, sexist, and classist doctrines, and that such “discoveries” have been championed by nonscientists interested in pursuing their own political agendas.32 The danger of racial corollaries from comparing nonhuman to human primate behavior was exemplified by Frederick Goodwin, director of the Alcohol Drug Abuse and Mental Health Administration, who declared in February 1992:
If you look, for example, at male monkeys, especially in the wild, roughly half of them survive to adulthood. The other half die by violence. That is the natural way of it for males, to knock each other off, and, in fact, there are some interesting evolutionary implications of that because the same hyper-aggressive monkeys who kill each other are also hyper-sexual, so they copulate more. Maybe it isn’t just the careless use of the word when people call certain areas of certain cities “jungles.”33
These comments referred to ADAMHA’s “Violence Initiative,” which
aimed to identify young children prone to later violence and expose them
to drug treatments to change their “anti-social” behavior.
Goodwin’s comments, although probably not intended as racist,
nevertheless produced strong reaction from African-American leaders,
who charged him with racism. His remarks did little to alleviate concerns
that the “Violence Initiative” was a smokescreen for social
and/or racial control.33 Furthermore, they demonstrated the
dangers of using nonhuman primate behavior as a model of human behavior,
for, despite the genetic similarity among other primates and humans,
the existing genetic differences are significant and create critical
differences in physiology and behavior.34 Whatever the actual
goals of “Violence Initiative” proponents, nonhuman primate
research was central to the plan because of its powerful metaphorical
effects.
3. Biomedical Research Risks
Using nonhuman primates as stand-ins for humans in invasive experiments poses
the risk of drawing misleading conclusions. For example, as discussed previously,
the leading monkey model of polio falsely indicated that the polio virus primarily
infected nervous tissue, misdirecting prevention measures and impeding vaccine
development. Yet, Yerkes director Frederick King observed, “Primates
became a key animal model for studies on the pathogenesis of polio,”35 even
though this model was fundamentally misleading.36 The limitations
of nonhuman primate research and the scientific risk of excessive faith in
its results have not been appreciated by animal researchers. For a variety
of political reasons, few scientists openly question whether animal modelling,
in general, or primate modelling, in particular, are reliable research methods.
One of the main obstacles to open discussion and debate of animal modelling’s
utility is that researchers, threatened by the animal protection movement,
believe that best strategy is to defend all animal research, regardless
of its actual, individual value.37,38 Also, in an effort to appear
united in their support of animal modelling, researchers discourage or actively
suppress criticism from within their ranks.39-42 This not only raises
further questions regarding animal modelling’s validity, but also undermines
academic integrity, which is a cornerstone of all intellectual inquiry.
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