English summary

Summary: Primate experiments

Experiments on primates effectively fall into two broad groups: academic research which is varied, and regulatory testing – required for products to be sold on the market – which are standardised.

Most of the monkeys arriving in European laboratories are used in the type of regulatory testing that is carried out at Huntingdon Life Sciences (or HLS).

One of Europe’s largest commercial animal testing facilities, HLS is contracted by pharmaceutical, chemical, industrial and other companies to perform toxicology (safety/effects testing) and other tests on their products.

This is one of the most secretive areas of animal experimentation. Permits for regulatory tests are granted in ‘groups’ and therefore individual sets of experiments are not scrutinised in advance by regulators. The reports of the tests are the property of the customer. Such experiments are rarely, if ever, published.

Between 2006 and 2008 an ADI/NAVS investigator studied the use of primates at HLS, which has a capacity for around 500 macaque monkeys. This study provides a rare insight into how these monkeys live and die behind closed doors.

On arrival monkeys are placed in a stock colony, with up to fifteen animals in a room little more than two metres wide and tall by three metres long, with a small catching cage, 1 metre by 2 metres tall. There is no natural light. These wild animals would normally live in trees, in large troops of fifty to one hundred monkeys, and might range over 1.5 kilometres in a day. Their HLS home provides an average of one cubic metre per animal.

The monkeys are moved to Unit M12 for experimentation. Some are now confined in cages of roughly one cubic metre. Three of these cages may be linked, with three monkeys sharing the space. Their rich natural habitat now replaced by a single horizontal bar in each cage.

These are the conditions provided by European and UK regulation for over twenty years, where it is acknowledged that, “Primates have high intelligence, most have arboreal habits and all need complex, stimulating environments.” The failure of these regulations to uphold standards, and the gulf between how welfare is perceived inside and outside of laboratories, is apparent from our photographs.

It would be difficult to describe the housing at HLS as anything more than the bare minimum. This is a wealthy company, providing a service to multi-billion pound/euro companies, yet these highly intelligent animals are provided with just enough to sustain them before they suffer in tests for products.

A monkey was discovered with blood on its face and the ends of the animal’s toes were missing. Some staff suggested that the monkey had chewed off its own toes, however our investigator noted that the wounds were clean straight cuts, and concluded that the animal was more likely to have trapped its foot in some part of the cage, sliced its toes off trying to free itself and then put its foot in its mouth. Missing digits were not considered to be an uncommon occurrence.

Monkeys had a range of cuts and injuries from the cages, with several requiring veterinary attention. Scrapes and scratches from being removed from cages; a chain being used to secure a cage pierced the cheek of a female, leaving her unable to eat and having to be force fed each day. Others suffered diarrhoea, nose bleeds, or ate and then vomited their own excrement.

Tests we observed used anything from 4 to 72 monkeys and all involved the physical restraint of the monkeys, which clearly caused them distress.
It takes three people to dose a small monkey by mouth. The “catcher” pins the animal’s arms, the “legger” takes the legs, and another feeds a rubber tube down the throat to the animal’s stomach and pumps in the test substance.

In other tests the monkeys are strapped down in chairs. For some the stress is so great that they suffer rectal prolapse, which is a known indicator of stress in restrained primates. During the study of an incontinence drug, three of the monkeys being restrained suffered rectal prolapses, and one being used to test a drug suffered repeated prolapses.

During an oral dosing study, several monkeys suffered from vomiting and salivation on numerous occasions. Several produced black-stained urine on their cage floor. One almost chewed off its whole finger and continued to chew its hand after the vet had dressed it. Others showed a range of symptoms such as tugging at chest skin, pushing their fists into their mouths, trying to bite through the metal food hopper, pushing large amounts of sawdust into cheek pouches, chewing metal and dragging teeth along the bars of the cage. Five days later, some showed signs of twitchy feet, indicating a kind of pins and needles sensation.

Several animals were clearly distressed, yet they were orally dosed as normal and returned to their cages. At around the same time, a study of the same product was started in rats and researchers had noticed the rats chewing their feet and eating sawdust. Almost chewing off a finger is a substantial clinical sign, so as a result the dose for one group was lowered.

This demonstrates how predictions of likely severity can be misjudged. The new European Directive needs to include a new system to report upon unexpected levels of suffering or other events, in order for improvements in protection of animals.

An inhalation study provided another example of how the severity of a procedure can be misjudged:

Over a period of time three monkeys on an inhalation study died or had to be killed due to partially collapsed and blocked lungs. Three other animals also collapsed but were revived. After death, it was found that these animals had blackened lungs. Clearly they would have suffered a great deal.

An additional fear and stress for laboratory monkeys is that they have the ability to anticipate what is going to happen to them. In the wild, these monkeys are intelligent, they innovate, learn from each other and pass on skills such as cleaning food or fishing. Yet at HLS caged monkeys were able to see other monkeys being strapped down and experimented upon.

Some monkeys had an incontinence drug pumped into their stomach every day for a year. Others were bled multiple times in a day, or day after day – enduring over eighty bleeds.

The ADI/NAVS investigator reported that on the days when the animals were killed and their bodies studied, the other monkeys would fall silent.
Stress and anticipation are both known to affect the outcomes of experiments and distort results.

Documents leaked from another contract testing laboratory, Inveresk in Scotland (ADI/NAVS report, 2005), show that during tests for an asthma drug, monkeys suffered with liquid faeces; redness of face, lips, feet and hands; swollen penises and scrota; a loss of body tone; low heart rate; hernias; they had body tremors and a quiet, hunched appearance.

There is an opportunity to end this suffering and improve science – governments must not waste it.