Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million used annually.
Animal tests have been abysmal predictors of drug safety because of innumerable physiological and pathological differences between species. The General Accounting Office reviewed 198 of 209 new drugs marketed from 1976 to 1985 and found that 52 percent had ''serious postapproval risks'' not predicted by animal tests. In the case of fenfluramine and dexfenfluramine, animal studies ''had never revealed heart abnormalities,'' according to the Food and Drug Administration.
U.S. agencies have already approved alternative tests to replace many experiments on animals' eyes and skin. Scientists are now developing tests for toxins that cause organ damage, birth defects, and other problems. These new tests could make animal toxicity experiments obsolete in the next 10 to 20 years, says David Jacobson-Kram, associate director for pharmacology and toxicology at the FDA's Center for Drug Evaluation and Research in Silver Spring, Md.
Estimates of animals used globally for experiments range from tens of millions to 100 million or more annually. Between 80 and 800 animals are now needed per drug. And there isn't universal agreement among scientists that ending testing on animals will ever be possible or should stop, considering the life-saving advances that have come from such studies, according to the Physicians Committee for Responsible Medicine.
Well over half of the millions of animals tested annually either die during testing or are killed after tests are completed, either to examine internal organs or simply because they are so crippled or sick from the lab tests. Cancers are injected into healthy animals, and injuries are intentionally afflicted externally to resemble joint problems. The Animal Welfare Act (AWA) only protects lab animals before and after testing.
Early Greek writings (circa 500 B.C.) describe the dissection of living animals by physician-scientists interested in physiological processes. Later, Roman physicians--including perhaps the single most influential figure in the emergence of the medical sciences, the physician Galen--began to perform what we would now regard as the first genuine experiments involving animals. Using vivisections to test specific hypotheses and explore competing explanations of biological phenomena, these early physician-researcher were among the first advocates of the idea that the use of animals in research was morally justifiable in light of the potential health benefits associated with those experiments.
Opposition to all animal testing would require a life without drugs, vaccines, painkillers, anesthetics and surgery. It would demand a rejection of all federally mandated Food and Drug Administration and Environmental Protection Agency tests that ensure the safe consumption of products in our homes and workplaces, ranging from the testing of components used in computers and cellphones to plastic wraps and chemical additives in our foods and drinks. In short, it would require a lifestyle far removed from that enjoyed by most people.
Although most laws do not explicitly require animal testing, requirements of safety implicitly require that the best available measures for determining safety be used. Thus alternatives are not likely to be used widely until they can be shown to be at least as valid and reliable as the tests being replaced.
When performing or contracting animal research for a given product, prospective clinical sponsors should adhere to the nine Principles in the U.S. Government Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training — which include minimizing pain and distress, employing trained animal-care personnel, and using the fewest possible animals and alternatives to animals when appropriate. In December 2010, FDA issued an advance notice of proposed rule-making (ANPRM) to advise the public of its intention to amend the regulations for Good Laboratory Practice (GLP) for Nonclinical Laboratory Studies so as to address animal welfare.
Technical improvements in tissue culture and the development of the Ames test, which uses bacteria to detect mutations, challenge the view that animal testing is the only option in toxicity testing. The costs of assessing potential health effects of some 200,000 substances per year that are newly identified or synthesized necessitate alternatives to animal testing. However, the new tools for toxicity testing must be looked on as adjuncts to traditional testing methods.
Animal testing programs have legitimized the continued production and use of millions of toxic chemicals. Federal scientists have relied on animal testing programs to make chemicals acceptable to regulators, attractive to consumers, and to protect themselves from costly litigation. Even when a chemical has caused cancer and other effects in animals, cost-benefit decisions play a key role in federal agencies' decisions to leave a chemical on the market.