Under the Microscope/Prof William Reville: Animals are widely used by the pharmaceutical industry to test medical preparations to ensure that they are safe for human consumption.
Most scientists would like to see such use of animals reduced to the minimum possible. Research programs are under way to develop alternatives to animal testing and recently Philippe Busquin, European Research Commissioner, announced a new alternative method to check for fever-causing agents (pyrogens) in non-oral drugs. It is estimated that substitution of this method for the traditional animal test will spare the lives of 200,000 rabbits per year.
Since the dawn of history, humankind has used animals for food, labour, transport, clothing, and sport. When we eventually developed the capacity to do science, we also began to use animals for scientific purposes. The use of animals in science is controversial and emotive. Some people believe that humans have no right to employ animals in this regard.
The various views that are expressed on the use of animals in science fall mainly into five categories: (1) humans have an absolute right to use animals as they see fit; (2) humans have a conditional right to use animals; (3) humans have a duty of care to animals; (4) humans have no right to use animals in any way; (5) results obtained from the use of animals in research are of no value to human medicine.
It is said that the family of Claude Bernard (1813-1878), the famous French physiologist, were horrified one day to find that, on returning home, Bernard was dissecting the family dog on the kitchen table. The idea that we have an absolute right to do as we please with animals is very old but is held by very few nowadays.
The idea was encouraged in science by the French philosopher Rene Descartes (1596-1650) who described animals as living machines incapable of suffering pain because they lack a soul. Although Descartes was vitally important in guiding science to ask only those questions that it can answer, his notions on animal physiology/psychology would not be taken seriously today.
The idea that animals have conditional rights recognises that animals have a legitimate place in the world and that humans can't do entirely as they please with them. In modern society the idea of conditional rights for animals would normally be extended to include the idea of the duty of humans to care for animals. This means that when we exploit animals by using them to produce, for example, food or labour, we have a duty to ensure that the animals are housed and fed and suffer a minimum of distress or pain.
A minority of people believe that humans have no rights to use animals, and that animals have natural rights that parallel human rights. In a nutshell, this view holds we cannot treat an animal in any way that would be considered unacceptable treatment of a fellow human being. Obviously people who hold this view must also be strictly vegetarian.
A small minority of people also believe that the use of animals in medical research is useless since the results cannot be extrapolated to humans because of species differences. As a biochemist, I can assure you that this view is wrong. The biochemical similarities between animals and humans are huge, and the results obtained with animals are of the greatest value in helping to understand the human condition.
Majority opinion nowadays would accept the conditional rights of animals and the duty of humans to care for animals. Most scientists regret having to use animals in biomedical research and take care to minimise animal distress. Efforts are ongoing to develop methods to get around the need to use animals in health research, for example the recent announcement of an alternative method to animal testing for the detection of pyrogens in non-oral drugs.
The pharmaceutical industry must take great care when producing drugs, vaccines, and medical devices that are to be implanted, to ensure that not only are they free of living micro-organisms but also of fragments of dead micro-organisms. If bacteria or bacterial fragments are allowed enter parts of the body that are usually bacteria-free, such as the bloodstream, great distress can ensue even culminating in death. In order to be sure that pharmaceutical products are safe, they must be tested before being released onto the market.
It was recognised over 50 years ago that when some sterile solutions are injected into humans or rabbits they cause a fever or a "pyrogenic" response. It was discovered that these fevers are caused by fragments of bacteria that remained even after sterilisation. A simple test was developed to screen samples for these pyrogens. A small amount of the sample under test is injected into a rabbit. If the rabbit develops a fever the sample is classified as pyrogenic and is rejected.
A new pyrogen test has now been developed which is carried out in a test tube instead of in rabbits.
The basis of the fever reaction is the release of certain chemicals by a blood cell called the monocyte when it comes into contact with a pyrogen. In the new method, the sample under test is simply reacted with a sample of human blood cells in a test tube.
Results to-date suggest that animal tests can be completely replaced by the new tests, saving up to 200,000 rabbits a year.
William Reville is associate professor of biochemistry and director of microscopy at University College Cork