Animal Aid

Monkeying around with human health

Drug testing

Using primates damages and kills people

Primates have failed researchers with regard to their ability to predict dangerous side effects of medications. For example:

'It is the actual results of teratogenicity [birth defect] testing in primates which have been most disappointing. Of the 15 listed putative human teratogens tested in non-human primates, only eight were also teratogenic in one or more of the various species...' - Dr. JL Schardein, author of 'Chemically Induced Birth Defects'.

Despite these failures, marmosets, in particular, are increasingly popular as the 'second species' - in addition to rodents - required by regulators responsible for licensing new drugs. They are attractive to pharmaceutical companies because they are small and easy to breed in captivity. Their size makes them cheaper than dogs to dose with expensive test compounds and easy to house in small cages and inhalation chambers.

These benefits are itemised in a paper published by the Association of the British Pharmaceutical Industry in 2001. (10) The paper notes, however, that marmosets are very excitable and can be difficult to handle. Their small size (and therefore blood volume) can be a problem when multiple blood samples are required. Skilled and experienced technicians are needed to dose marmosets intravenously, to take blood from their femoral (thigh) artery, or to dose them by 'gavage' - a long tube pushed down the throat to the stomach. Marmosets cannot be trained to tolerate these procedures and must be restrained and even sedated.

Stolen from the wild

Not only do monkeys endure the trials of laboratory life, many are imported from such distant countries as Mauritius, Israel, Indonesia, the Philippines and China. 53% of procedures in 2001 involved animals imported from such sources outside the EU. Investigations by the British Union for the Abolition of Vivisection (Paradise Lost available at and by the RSPCA (Counting the Cost: available at reveal appalling conditions at some breeding centres, which are often founded, re-stocked and augmented with animals trapped from the wild. Capture from the wild causes huge distress. The first-generation offspring are sold to UK laboratories, having been taken from their mothers as young as six months old. Their journeys to the UK are in tiny, cramped crates and can last as long as three days - some monkeys have died in transit.

Species under threat

Concern about the use of macaques, in particular, is heightened by their conservation status. Long-tailed (also known as crab-eating or cynomolgus) macaques and rhesus macaques are the most commonly used species. They are 'old world' monkeys, native to Asia, where they live in large social troops that sometimes number 100 individuals. They are very communicative and maintain close relationships through mutual grooming. The long-tailed macaque is listed as near-threatened on the 2000 International Union for the Conservation of Nature 'red list'. The Japanese macaque is listed as endangered; yet up to 2,000 are captured and sold to Japanese laboratories every year. China is the main source of rhesus monkeys for Britain but housing conditions there are particularly horrifying. Breeding stock is taken from wild populations, which are in serious decline.

'Drawing from the wild poses an additional threat to the conservation status and, ultimately, survival, of some species and local populations.' Counting the Cost, report by the RSPCA (see above)

Monkey data is rubber-stamped

UK law states that the use of primates is permissible only if the researchers can demonstrate that no 'lower' species could be used instead. Yet regulators (the Medical Healthcare Products Regulatory Authority in the UK) accept marmoset toxicity data without query. This further encourages their use purely in order to gain easy official approval.

A fundamental point is that the use of primates - or indeed any animal species - for medical research has never been properly scientifically evaluated to see if their use produces benefits for human medicine. This was confirmed when Portsmouth South MP, Mike Hancock - on March 31 2004 - asked an apparently innocuous parliamentary question of the Home Secretary. 'What recent research', Hancock wanted to know, had his Department 'commissioned and evaluated on the efficacy of animal experiments?'

The answer was unequivocal. 'The Home Office has not commissioned or evaluated any formal research on the efficacy of animal experiments.' In the language of tabloid newspapers, this admission was a 'bombshell'. Here was the government department in charge of regulating vivisection admitting that it had - neither recently, nor at any other time - bothered to assess in a systematic way whether experimenting on animals produced beneficial results for people. The starkness of the admission was made all the more glaring by the 'cut and paste' paragraphs that followed it in the formal written answer to Hancock. 'Animal experiments must be judged to be potentially efficacious in order to be licensed under the Animals (Scientific Procedures) Act 1986, which requires that animals may only be used in scientific procedures where such use is fully justified, where the likely benefits outweigh the costs to the animals involved, and where the procedures are most likely to produce satisfactory results.'

The startling inconsistency in this answer is hardly difficult to detect - the Home Office will never grant permission for animals to be experimented upon, it was saying, unless it is sure that such experiments produce benefits that outweigh the harm done to the animals. Yet it has never itself bothered to develop a formal test - based on its own research or anyone else's - by which it can make such a judgement

'Most of the animal tests we accept have never been validated. They evolved over the past 20 years and the FDA is comfortable with them.' - Anita O'Connor, Food and Drug Administration (USA) (11)

Better research methods

There are more reliable methods to predict the safety and effectiveness of drugs for people. These include in vitro (test tube) studies using human cells and tissues, and sophisticated computer simulations designed to mimic human metabolism. A ten-year international study proved that human cell culture tests are more accurate and yield more useful information about toxic mechanisms than traditional animal tests. (12) The British company Pharmagene uses human tissue exclusively, noting that 'a flood of new data on human genetics is making drug research in animals redundant. If you have information on human genes, what's the point in going back to animals?' (13)

Screening new drugs in silico (on computer) is now taking the place of many animal tests. German biotech company 4SC designs new drugs entirely in silico and can process in one day what would take other biotechs a month. 'The time is fast approaching when what we are doing will be the industry norm,' says chief executive, Ulrich Dauer. 'We have the accuracy, the speed and we don't waste time with drugs that are not going to work.' (14)

The following example illustrates the ineffectiveness of assessing drug safety in animals and the impossibility of detecting subtle human responses: Eight out of ten drugs that were withdrawn from the US market between 1998 and 2001 had serious side effects in women that had not occurred in men. (15) All of them had, of course, been tested extensively in animals before they were released onto the market.

If men cannot predict the effects of drugs for women, how on earth can we expect to obtain reliable data from monkeys?

Infectious disease research

Failure of the 'animal model'

Investigating diseases that infect humans in any species other than humans is nonsensical, as pathogens and immune responses to them are highly species specific. For instance, chimpanzees are essentially immune to the human AIDS virus, Hepatitis B and C viruses, the malaria parasite and many other pathogens to which humans are susceptible.

'Up to this very day, all infectious diseases affecting humans are far from having appropriate animal models and, even in those cases where such infections are possible, the symptoms observed in animals and the course of the disease are often very different from those encountered in humans.' - Handbook of Animal Models of Infection, Academic Press, 1999, p.7

The recent anthrax attacks in the US mail were initially not taken seriously enough because experiments on monkeys showed the bacterium was not fatal until 8-10,000 spores are inhaled. When people died from much smaller doses it became apparent that this does not apply to humans.

The same failings apply to vaccine development:
'...prevention [of polio] was long delayed by the erroneous conception of the nature of the human disease based on misleading experimental models of the disease in monkeys.'
(16) - Dr. Albert Sabin, MD, inventor of the polio vaccine

Despite mounting evidence of vaccine research failures in animals, tens of thousands of primates and other animals have been killed in AIDS research over the past 20 years. This is despite the fact that infecting animals, even chimpanzees, with HIV does not produce an equivalent disease to human AIDS.

Chimpanzee AIDS research abandoned

This reality has long been recognised by many in the research community and by AIDS activists, who have campaigned hard against futile vaccine research in monkeys.

'What good does it do you to test something [a vaccine] in a monkey? You find five or six years from now that it works in the monkey, and then you test it in humans and you realise that humans behave totally differently from monkeys, so you've wasted five years.' (17) - Dr. Mark Feinberg, leading AIDS researcher

After an extensive review of the American AIDS research programme, the US government concluded that chimpanzees are a deficient 'model' for use in AIDS research and redirected $10 million of funding. Even the director of the Yerkes Primate Centre admitted that 15 years of AIDS research in chimpanzees had produced little data relevant to humans. (18)

Everything we know about HIV and AIDS has been learned from studying people with the disease - through epidemiology and in vitro research on human blood cells. Using primates to predict how humans will respond is not simply unproductive, it has resulted in medical catastrophe. In the early 1980s, the observation that HIV did not affect chimpanzees led scientists to assume that the virus would be harmless to humans too. They consequently advised health authorities to allow transfusions with contaminated blood samples, thereby giving rise to the French blood scandal that claimed thousands of innocent victims.

False promise

The first five-year trial of an HIV vaccine, 'Aidsvax', based on success in animals has recently been pronounced a failure. (19) The 8,000 high-risk volunteers in the trial were not protected from HIV infection by the vaccine. Many thousands of participants have been given false expectations which have been cruelly dashed.

Far too frequently, animal models have been used to develop vaccines that are effective in laboratory animals but are ineffective, or actually harmful, in humans. AIDS is a terrible illness, and research money and personnel need to be directed toward methodologies that are viable. Using an archaic methodology like animal models to combat a 21st century disease is more than foolish, it is immoral.

Brain research

Exercise in futility

Experimenting on monkeys with the hope of unlocking the secrets of the human brain is an exercise in futility. The most dramatic difference between humans and any other species, including the great apes, is found in the central nervous system. Our brain is four times larger than that of a chimpanzee, which is four times larger than that of a macaque. The human brain is enriched with specific cell types implicated in communication, language, comprehension and autonomic functions.

'For cortical regions, such as the language areas, we cannot use the macaque brain even as a rough guide as it probably lacks comparable regions.' (20) - Francis Crick, co-discoverer of the structure of DNA

In addition to anatomical differences, the pattern of gene expression in our brain is dramatically different from that of the chimpanzee. (21) Humans are distinguished from all mammals by their lack of a particular sugar molecule on the surface of cells, especially in the brain. It is likely that this profoundly affects brain development and function. Biochemical pathways in the human brain are unique. (22)

Many of the attributes that we most celebrate - such as our ability to express ourselves in prose, poetry, song and dance - are uniquely human. We are clearly different, very different, from chimpanzees.

Yet at British universities, including Oxford, Cambridge, Manchester and London, monkeys are still used - at taxpayers' expense - as models of human brain function.

This is despite the fact that human brains can now be studied non-invasively using high-tec scanners. These enable the conscious brain to be observed while engaged in a variety of cognitive tasks (e.g. talking, singing, reading, writing) of which monkeys are not capable - and thus could clearly not provide any relevant insight.

State-of-the-art research

Functional MRI scanners can monitor the brain activity of volunteers undertaking tests of memory and other skills, to reveal brain areas that are active during particular activities. Transcranial magnetic stimulation (TMS) temporarily disrupts brain function, allowing scientists to assess the impact of 'switching off' specific regions without permanently removing them. The Dr Hadwen Trust for Humane Research is funding such studies into epilepsy research at Oxford University. There are many other state-of-the-art imaging techniques now available, including PET (positron emission topography), CAT (computer-aided tomography), MEG (magnetoencephalography), EROS (event-related optical signals) and VBM (voxel-based morphometric analysis). These remarkable techniques are able to differentiate such subtleties as musical ability or whether someone is lying or how hard they are concentrating. Insights that can be gleaned from monkeys seem absurdly crude by comparison.

One recent study of macaque monkeys at Oxford University was aimed at determining the role of the cerebellum in cognition, by making a series of lesions in their cerebella. (23) The monkeys' skulls were opened and 16 separate injections were made of an acid into the right hemisphere, followed a week later by further open-skull surgery and 16 injections into the left hemisphere. The animals were then tested, thousands of times, on cognitive tasks they had been trained to perform before their brain damage. Then they were killed and their brains extracted for analysis. The experiment served only to emphasise the difference between human and monkey brains, by contradicting similar studies that had already been conducted with brain-damaged human subjects. Self-evidently, the only way to investigate human brain function is to study the human brain. Results from the brains of any other species are simply misleading.

Send this page to a friend

Read about how we treat your data: privacy policy.

© Copyright Animal Aid 2014