The case for using pigs.

The question of whether or not to use pigs, genetically altered to minimize the likelihood of organ rejection, as sources for transplantable organs seems to hinge only on whether xenografting poses an intolerable danger to public health. As Dr Daar accurately notes in his comprehensive review of the state of xenografting, recent debates about the morality of xenografting in the United States and Europe, especially the United Kingdom, have arrived at different answers to the question based on their assessment of the public health risk posed. The decision in Europe has been that the threat to public health of disease transmission is too great, given the limited knowledge available, to justify clinical trials of any xenografts at the present time. Expert panels in the US are not so convinced of the dangers, and see the science as more promising. In one way the differences between the American and European assessment of the morality of xenografting reflect deep cultural differences in attitudes toward biomedicine and science. Americans tend to be more positive toward the promise of science then do Europeans, who tend toward caution in their assessment of risk when it derives from scientific activities. Strangely, it is also the case that for all the difficulty that surrounds the computation of the risks posed by transmission of viruses and microorganisms to people from animals, questions of safety provide a framework within which scientists and policy-makers are comfortable. Attitudes and answers may differ from country to country, but there are no sticky, complex or ineffable ethical issues to tackle if the debate about xenografting can be reduced to a question of safety. Public safety surely must be a primary consideration in deciding whether or not genetically modified animals ought be used as sources of organs for people in need of transplants. The threat of a public health catastrophe caused by a lethal virus transmitted from a pig or primate to a human transplant recipient and thence to a large segment of the human population is small but real. It is a risk that cannot be justified simply by the possibility of saving a comparatively small number of lives by means of transplants. But, as Daar correctly and insightfully perceives, the ethics of xenografting involves more than an analysis of the safety question. Equally important questions in assessing the morality of xenografting are whether it is ethical to breed and kill pigs or other animals for this purpose; whether it is ethical to ask a human subject to face the risks, emotional as well as physical, that will attend any attempt to xenograft; or whether the psychosocial issues raised for recipients are too great to bear. Each of these issues must be answered in a way that the public finds convincing. I suspect this will require clinical research in xenografting to follow very specific protocols if it is to be an option for solving the problem of scarce supply in the field of organ transplantation. There should be no doubt that serious risks are posed when organs from any animal are placed inside a human body. It is a well-established fact that many viral and prion agents are capable of moving from animal vectors to humans. The natural defences of the human body against viruses and other microorganisms that can be carried along in an animal organ may well be compromised when that organ comes into direct contact with the body's own internal organs and fluids. It might be supposed that the danger posed is greatest with the earliest experiments, but this is not true. It may well be easier to manage the danger of transmission and infection by animal-borne viruses and microorganisms in the earliest stages of xenografting than later in the development of the technology. The first experiments can be done under very carefully controlled conditions. Those involved in the first xenografts can be closely monitored. Recipients can be rigorously isolated and those who come into close contact with them can be required to wear appropriate protective clothing and equipment. …