Should Labs Treat Chimps More Like Humans?
for National Geographic News
|September 6, 2005|
The announcement last week that scientists have pieced together the href="http://news.nationalgeographic.com/news/2005/08/0831_050831_chimp_genes.html">genome sequence of the chimpanzeeand found that
humans and chimps are 96 percent similarhas reignited a debate
over the ethics of biological research using chimpanzees.
Up to 3,000 great apes (mostly West African chimpanzees) live in captivity in the United States. Some are housed in zoos and sanctuaries. But many were bred for medical research. Two federally funded research institutions use chimps for biomedical experiments.
Chimp research proponents point out that important medical advances, such as the development of a hepatitis B vaccine, have been achieved through research with chimpanzees.
Predicting that chimps will play an even greater role in future biomedical advances, scientists warn of a decline in the population of captive chimps available for research. The researchers argue that a federal moratorium on the breeding of chimps in laboratories should be lifted.
Other researchers, however, say that they have an ethical responsibility to treat chimps differently than other research animals. Critics point to the animals' genetic similarity to humans, their ability to use tools, and their sense of "self."
"Chimps are not lab rats or mice, they're unique animals," said Pascal Gagneux, an evolutionary biologist and primate expert at the University of California, San Diego.
In an article in the science journal Nature, Gagneux and colleagues went so far as to recommend that studies using chimpanzees should follow ethical principles generally similar to those currently used in studies on human subjects who are unable to give informed consent.
Great ape numbers in the wild have fallen to tens of thousands, and the chimpanzee is considered an endangered animal. A recent United Nations report asserted that every one of the great ape species is at high risk of extinction, either in the immediate future or, in best-case scenarios, within 50 years.
Because of their biological similarities to humans, chimps have long been used in laboratory research in place of human subjects to test, among other things, new drugs.
In the 1980s and 1990s, the U.S government supported the breeding of chimpanzees to be used for HIV research. But scientists found that the immune system of chimps does not succumb to the HIV virus. The use of chimps in HIV studies was eventually replaced by work with monkeys.
But the breeding program contributed to overproduction of research chimps. The U.S. National Institutes of Health (NIH) subsequently introduced a five-year moratorium on breeding chimps for laboratory research in 1996.
The moratorium has been extended annually since 2001. National Geographic News has learned that the NIH-affiliated National Center for Research Resources (NCRR), which oversees federally funded primate research, has recommended that the breeding ban be extended for at least one more year.
"Chimps are very expensive animals to keep they need good-sized facilities, and live for a long time," said John Harding, the director of primate resources at NCRR, which is based in Bethesda, Maryland.
Scientists on both sides of the issue agree that there is little doubt that chimpanzees can be of great biomedical research value.
Researchers are now using chimps to test special antibodies known as monoclonal antibodies, which are genetically engineered to be almost identical to human antibodies, in the hope of finding cancer treatments.
"Other species will try to reject these monoclonals, but chimps won't because their system is very much like ours," said Stuart Zola, director of the Yerkes National Primate Research Laboratory at Emory University in Atlanta, Georgia.
He says the recent sequencing of the chimp genome will help scientists better understand human-specific diseases, as well as human evolution and traits such as language.
Yerkes is one of two NIH-funded facilities that use chimps for biomedical research. The other is the Southwest National Primate Center in San Antonio, Texas.
Zola and John VandeBerg, who directs the Southwest National Primate Center, warned in another Nature article that the number of chimpanzees available for research is declining. The pair argued that the breeding moratorium should be lifted.
Scientists' understanding of the physiology of chimps is still limited. Some researchers say that despite the genetic and biological similarities, humans and chimps differ greatly in their susceptibility to some diseases.
"Chimps are surprisingly bad models for human disease," Gagneux, the UC San Diego scientist, said. "Diseases don't progress in chimpanzees like they do in humans."
Gagneux calls for stricter guidelines for the ethical and humane treatment of research chimpanzees. While NIH rules stipulate that chimps can only be used for invasive experiments when no other animal model can be used, Gagneux would like to see a ban on all research that harms chimps.
"I'm not against animal experiments in principle, but I believe we can study chimpanzees without doing irreparable harm to them," he said.
"But if a completely new Hanta virus is discovered tomorrow that threatens to take over the world, and it turns out that doing something harmful to chimpanzees could immensely increase our knowledge of the virus, we would have to weigh that option."
Gagneux says biomedical researchers have special ethical responsibilities toward great apes. Among all the animals used in labs, chimps seem to be the only ones that are self-aware, and that puts them in a special category, he says.
Zola, the Yerkes director, disagrees.
"I don't think we should make a distinction between our obligation to treat humanely any species, whether it's a rat or a monkey or a chimpanzee," he said. "No matter how much we may wish it, chimps are not human."
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