A Critical Look At Animal Experimentation

The following essay is reprinted from a Medical Research Modernisation Comittee booklet.

Murry J. Cohen, M.D.
Stephen R. Kaufman, M.D.
Rhoda Ruttenberg, M.D.
Alix Fano, M.A.

Increasing numbers of scientists and clinicians are challenging animal experimentation on scientific grounds. Considerable evidence demonstrates that animal experimentation is inefficient and unreliable, while newly developed methodologies are more valid and less expensive than animal studies.

Historical impact of animal experimentation
Proponents of vivisection (tests, experiments and "educational" exercises involving harm to animals) claim that it has played a crucial role in virtually all medical advances. However, several medical historians argue that the key discoveries in such areas as heart disease, cancer, immunology, anesthesia and psychiatry were in fact achieved through clinical research, observation of patients, and human autopsy.

Human data have historically been interpreted in light of laboratory data derived from non-human animals. This has resulted in unfortunate medical consequences. For instance, by 1963 prospective and retrospective studies of human patients had already shown a strong correlation between cigarette smoking and lung cancer. In contrast, almost all experimental efforts to produce lung cancer in animals failed. As a result, Clearance Little, a leading cancer animal researcher, wrote, "The failure of many investigators to induce experimental cancers, except in a handful of cases, during the fifty years of trying, casts serious doubt on the validity of the cigarette-lung cancer theory." Because the human and animal data failed to agree, this researcher and others distrusted the more reliable human data. As a result, health warnings were delayed for years, while thousands of people died of lung cancer.

By the early 1940s, human clinical investigation strongly indicated that asbestos caused cancer. However, animal studies repeatedly failed to demonstrate this and proper workplace precautions were not instituted until decades later. Similarly human population studies have shown a clear risk from exposure to low-level ionizing radiation from diagnostic X-rays and nuclear wastes, but contradictory animal studies have stalled proper warnings and regulations. Likewise, while the connection between alcohol consumption and cirrhosis is indisputable in humans, repeated efforts to produce cirrhosis by excessive alcohol ingestion have failed in all non-human animals except baboons, and even baboon data are inconsistent.

Many other important medical advances have been delayed because of misleading information derived from animal "models". The animal model of polio, for example, resulted in a misunderstanding of the mechanism of infection. Studies on monkeys falsely indicated that poliovirus infects only the nervous system. This erroneous assumption resulted in misdirected preventive measures and delayed the development of tissue culture methodologies critical to the discovery of a vaccine. While monkey cell cultures were later used for vaccine production, it was research with human cell culture that first showed that poliovirus could be cultivated on non-neural tissue. Similarly, development of surgery to replace clogged arteries with the patients own veins was impeded by dog experiments which falsely indicated that veins could not beused. Likewise, kidney transplants, quickly rejected in dogs, were accepted for a much longer time in human patients. We now know that kidney failure suppresses the immune system, which increases tolerance of foreign tissues.

Nevertheless, the public continues to endorse vivisection, primarily because many people believe that animal experimentation has been vital for most medical advances. However few question whether such research has been necessary or even, on balance, helpful in medical progress.

 

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