Chimpanzees are our closest animal relative. So close, in fact, that 98 percent of a chimpanzee's DNA is identical to that of humans.
The highly intelligent primates share many of our physical and behavioral characteristics and that similarity has made them attractive to medical researchers, sparking a heated debate over animal rights and medical ethics.
Essential or inhumane
The United States is the only country in the world that still allows federally-funded medical experiments on chimpanzees. The practice includes developing and testing new vaccines and drugs that might prevent or cure potentially-fatal human diseases.
Supporters of the practice say medical tests involving chimps have helped save millions of lives worldwide. Animal welfare activists argue that subjecting chimpanzees to painful, and often lethal, experiments is cruel and inhumane.
Dr. Hope Ferdowsian, director of research policy at the nonprofit Physicians Committee for Responsible Medicine (PCRM), says chimpanzees used for HIV and hepatitis research are anaesthetized with a dart gun before being subjected to harmful and invasive procedures. Besides its ethical objections, PCRM argues that the use of chimpanzees in the lab is an ineffective way to advance medical research.
Ineffective in humans?
Elizabeth Kucinich, wife of U.S. Congressman Dennis Kucinich, is a long-time animal welfare advocate. She also serves as director of public affairs for the Physicians Committee.
Kucinich says science has evolved since the 1920s when primates were first used for experimentation. "Since that time we've really learned that as close as they are to human species, they're not close enough for any real scientific outcomes for drug testing."
According to Kucinich, over 80 different HIV-related vaccines have worked in chimpanzees but none have proven effective in human beings.
A recent undercover investigation conducted by the Humane Society of the United States found chimpanzees in a Louisiana research center being subjected to harsh treatment and painful medical experiments.
They also found these highly social animals living in small, prison-like cages where some have languished for decades.
Humane Society president Wayne Pacelle says it isn't just the physical abuse of the chimpanzees that's troubling. "I think the larger issue is the psychological torment; animals isolated, kept away from others who can give them companionship, fearing what's going to happen next, and animals living in this constant state of confinement."
Hope Ferdowsian of the Physicians Committee says chimpanzees don't have to suffer like this and explains that there are alternatives to the use of chimpanzees in research. "For example, in HIV research, we've learned a lot from human epidemiological studies and ethically conducted clinical trials," she says. "We've also learned a lot about the virus from mathematical and computer modeling. For hepatitis C vaccine we're learning a lot from in vitro or cell-based methods."
Ninety-eight percent of a chimpanzee's DNA is identical to that of humans.
Banning experiments on chimps
Both Kucinich and Ferdowsian were on Capitol Hill recently, campaigning for newly introduced congressional legislation that would eventually ban invasive experiments on chimpanzees.
According to Ferdowsian, the Great Ape Protection Act, or GAPA, "would ban all invasive and harmful research on chimpanzees in American laboratories." It would also "release federally-owned chimpanzees, about half of the thousand chimpanzees that are languishing in American laboratories today, to sanctuaries."
But the legislation is not to everyone's liking. John VandeBerg, director of the Southwest National Primate Research Center in San Antonio, Texas, says the use of chimpanzees in biomedical research is essential.
He argues that there are no other animals that can be infected with Hepatitis C virus, Hepatitis B Virus or HIV.
"So in order to develop drugs to treat people who have Hepatitis B, Hepatitis C, particularly, we need to use chimpanzees to determine if the drugs can reduce the level of viruses in their blood and in their livers," says VandeBerg.
While he acknowledges that there is much to be learned from alternative research methods like cell culture - a process by which cells are taken from a living organism and grown under controlled conditions - VandeBerg says they have learned a lot more from research on chimpanzees.
"There are hundreds of millions of people who suffer from hepatitis-B and hepatitis-C, the two diseases which are most important for the moment for chimp research," says Dr. John VandeBerg, director of the Southwest National Primate Research Center.
"For example," he says, "we cannot determine if a drug is going to work in a human being, and be safe in a human being by testing that drug in cell culture models. We must determine first if it's going to work in a living animal that has all the complexities of a human being."
VandeBerg says he and his colleagues go out of their way to use lower forms of animals before experimenting on chimpanzees. "When the research progresses to a stage when the information coming from mice and rats is not sufficient, we may move up to using monkeys. And when monkeys can't give us the answers we need, only then, do we move to the chimpanzee."
VandeBerg also points out that the research that's been conducted on chimpanzees so far has already benefited much of the world's population.
"Three hundred and fifty million human beings in the world are infected with Hepatitis-B virus. Three hundred million people in the world are infected with Hepatitis-C virus. That's almost a tenth of the world's population," says VandeBerg. "It would be unethical for us to turn our back on these people and not conduct the research that is so desperately needed to develop the drugs to treat these diseases and the vaccines to prevent them in the future."
Vandeberg also defends his research facility, saying that the animals in his primate research center receive better care than most people in the world. "They live in social groups, they live in indoor-outdoor enclosures, they have heating in the winter and air conditioning in the summer; our chimps even have televisions," he says.
World renowned primate expert Jane Goodall believes using chimpanzees in medical research is "morally wrong and unacceptable".
But such creature comforts don't change the fact that chimpanzees used in medical research may suffer or die, and that's unacceptable to famed primate expert Jane Goodall. She spent decades studying and living among Central African chimpanzees in the wild and now campaigns to protect the endangered species.
"We need to recognize at the outset that what we do to animals - from their perspective certainly, and probably from ours - is morally wrong and unacceptable, and that it's really important to follow through on all these exciting new leads into ways of doing research without using animals," says Goodall.
But John VandeBerg of the Southwest National Primate Research Center says if the proposed legislation to phase out medical research on chimpanzees is passed, scientists like him will have to end their work. "It will be a great tragedy for humanity if research with chimpanzees were stopped."
The Great Ape Protection Act is currently making its way through the U.S. Congress. It has more than 140 co-sponsors in the House of Representatives. While the proposed ban awaits Congressional action, medical testing on chimpanzees will continue to be a highly divisive – and hotly debated – issue.