General NHPs are used in research into HIV, neurology, behavior, cognition, reproduction, Parkinson's disease, stroke, malaria, respiratory viruses, infectious disease, genetics, xenotransplantation, drug abuse, and also in vaccine and drug testing. According to
The Humane Society of the United States, chimpanzees are most often used in hepatitis research, and monkeys in
SIV research. Animals used in hepatitis and SIV studies are often caged alone. Toxicology testing is the largest use, which includes legislatively required testing of drugs. The second largest category of research using primates is "protection of man, animals, or environment", accounting for 8.9% of all procedures in 2006. The third largest category is "fundamental biological research", accounting for 4.9% of all UK primate procedures in 2006. This includes neuroscientific study of the visual system, cognition, and diseases such as Parkinson's, This is contradicted by Dr.
Gill Langley of the British Union for the Abolition of Vivisection, who gives as an example of re-use the licence granted to Cambridge University to conduct
brain experiments on
marmosets. The protocol sheet stated that the animals would receive "multiple interventions as part of the whole lesion/graft repair procedure." Under the protocol, a marmoset could be given acute brain lesions under general anaesthetic, followed by tissue implantation under a second general anaesthetic, followed again central cannula implantation under a third. The re-use is allowable when required to meet scientific goals, such as this case in which some procedures are required as preparatory for others.
Methods of restraint One of the disadvantages of using NHPs is that they can be difficult to handle, and various methods of physical restraint have to be used. Viktor Reinhardt of the Wisconsin Regional Primate Research Center writes that scientists may be unaware of the way in which their research animals are handled, and therefore fail to take into account the effect the handling may have had on the animals' health, and thereby on any data collected. Reinhardt writes that primatologists have long recognized that restraint methods may introduce an "uncontrolled methodological variable", by producing resistance and fear in the animal. "Numerous reports have been published demonstrating that non-human primates can readily be trained to cooperate rather than resist during common handling procedures such as capture, venipuncture, injection and veterinary examination. Cooperative animals fail to show behavioural and physiological signs of distress." Reinhardt lists common restraint methods as: squeeze-back cages, manual restraint, restraint boards, restraint chairs, restraint chutes, tethering, and nets. The U.S. is the world's largest user of chimpanzees for
biomedical research, with approximately 1,200 individual subjects in U.S. labs as of middle 2011, dropping to less than 700 as of 2016. Japan also still keeps a dozen chimpanzees in a research project for chimpanzee cognition (see
Ai (chimpanzee)). Chimpanzees routinely live 30 years in captivity, and can reach 60 years of age. defined as "inoculation with an infectious agent, surgery or biopsy conducted for the sake of research and not for the sake of the chimpanzee, and/or drug testing." Two federally funded laboratories have used chimps:
Yerkes National Primate Research Center at
Emory University in Atlanta, Georgia, and the Southwest National Primate Research Center in San Antonio, Texas. By 2008, five hundred chimps had been retired from laboratory use in the U.S. and live in sanctuaries in the U.S. or Canada. Animal sanctuaries were not an option until the first North American sanctuary that would accept chimpanzees opened in 1976. In 1986, to prepare for research on AIDS, the U.S. bred them aggressively, with 315 breeding chimpanzees used to produce 400 offspring. By 1996, it was clear that SIV/HIV-2/SHIV in macaque monkeys was a preferred scientific AIDS model to the chimpanzees, which meant there was a surplus. A five-year moratorium on breeding was therefore imposed by the U.S. National Institutes of Health (NIH) that year, and it has been extended annually since 2001. As of October 2006, the chimpanzee population in US laboratories had declined to 1133 from a peak of 1500 in 1996. The oldest known chimpanzee in a U.S. lab is Wenka, who was born in a laboratory in Florida on May 21, 1954. She was removed from her mother on the day of birth to be used in a vision experiment that lasted 17 months, then sold as a pet to a family in North Carolina. She was returned to the Yerkes National Primate Research Center in 1957 when she became too big to handle. Since then, she has given birth six times, and has been used in research into alcohol use, oral contraceptives, aging, and cognitive studies. With the publication of the
chimpanzee genome, there are reportedly plans to increase the use of chimpanzees in labs, with scientists arguing that the federal moratorium on breeding chimpanzees for research should be lifted. Other researchers argue that chimpanzees are unique animals and should either not be used in research, or should be treated differently. Pascal Gagneux, an evolutionary biologist and primate expert at the
University of California, San Diego, argues that, given chimpanzees' sense of self, tool use, and genetic similarity to human beings, studies using chimpanzees should follow the ethical guidelines that are used for human subjects unable to give consent. On December 15, 2011, the
Institute of Medicine committee concluded in their "Chimpanzees in Biomedical and Behavioral Research: Assessing the Necessity" report that, "while the chimpanzee has been a valuable animal model in past research, most current use of chimpanzees for biomedical research is unnecessary," as scientific research indicated a decreasing need for the use of chimpanzees due to the emergence of non-chimpanzee models. Later that day
Francis Collins, a head of the NIH, said the agency would stop issuing new awards for research involving chimpanzees until the recommendations developed by the IOM are implemented. On 21 September 2012, the NIH announced that 110 chimpanzees owned by the government were to be retired. The NIH owned about 500 chimpanzees for research, and this move signified the first step to wind down its investment in chimpanzee research, according to Collins. Housed at the
New Iberia Research Center in
Louisiana, 10 of the retired chimpanzees were to go to the chimpanzee sanctuary
Chimp Haven while the rest were to go to
Texas Biomedical Research Institute in
San Antonio. However, concerns over the chimpanzees' status in the Texas Biomedical Research Institute as ‘research ineligible’ rather than ‘retired’ prompted the NIH to reconsider the plan. On 17 October 2012, it was announced that as many chimpanzees as possible will be relocated to Chimp Haven by August 2013, and that eventually all 110 will move there. In 2013 the NIH agreed with the IOM's recommendations that experimentation on chimpanzees was unnecessary and rarely helped in advancing human health for infectious diseases and that the NIH would phase out most of its government-funded experiments on chimpanzees. On 22 January 2013, an NIH task force released a report calling for the government to retire most of the chimpanzees under U.S. government support. The panel concluded that the animals provide little benefit in biomedical discoveries except in a few disease cases which can be supported by a small population of 50 primates for future research. It suggested that other approaches, such as genetically altered mice, should be developed and refined instead. On 13 November 2013,
Congress and the
Senate passed ‘The Chimpanzee Health Improvement, Maintenance and Protection Act’, which approved funding to expand the capacity of Chimp Haven and other chimpanzee sanctuaries, allowing for the transfer of almost all of the apes owned by the federal government to live in a more natural and group environment. The transfer was expected to take up to five years, at which point all but 50 chimpanzees were to have been successfully ‘retired’. On 11 June 2013, the
US Fish and Wildlife Service (USFWS) proposed to list captive chimpanzees as endangered, matching its existing classification for wild chimpanzees. Until the USFWS proposal, chimpanzees were the only species with a split listing that did not also classify captive members of the species as endangered. Before the proposal gained final approval, it was unclear what effect it would have on laboratory research. In November 2015 the NIH announced it would no longer support biomedical research on chimpanzees and release its remaining 50 chimpanzees to sanctuaries. The agency would also develop a plan for phasing out NIH support for the remaining chimps that are supported by, but not owned by, the NIH. In January 2014,
Merck & Co. announced that the company will not use chimpanzees for research, joining over 20 pharmaceutical companies and contract laboratories that have made the commitment. As the trend continues, it is estimated the remaining non-government owned 1,000 chimpanzees will be retired to sanctuaries around 2020. ==Notable studies==