Bit of an animalBMJ 2010; 340 doi: https://doi.org/10.1136/bmj.b5595 (Published 07 January 2010) Cite this as: BMJ 2010;340:b5595
- Geoff Watts, freelance journalist
When Australia’s National Health and Medical Research Council declared in mid-December that the country’s five year moratorium on animal to human xenotransplantation should be allowed to lapse, the move marked another step towards the reacceptance of this controversial procedure. It does not mean, however, that the fears of infection that originally prompted the procedure’s fall from grace have been entirely overcome. Throughout the existence of our species, pathogens have periodically crossed the gap separating us from other animals. The microbes have found a new home—but we have been saddled with a new disease, and sometimes with a disaster.
Given this state of affairs it would be foolish indeed to give any microbe a helping hand. If xenotransplantation is to move out of the research laboratory and into routine practice, medical staff will need convincing answers to three questions. Will the animal organ function in its new surroundings? Can measures be taken to prevent its rejection? And is there any risk of transmitting a disease to the recipient? Work during the past couple of decades has not given researchers complete answers to the first two questions, but the findings have been sufficiently encouraging to retain their interest and enthusiasm. That leaves the third concern: the possibility of transmitting an infection. Paradoxically, this may not be a problem at all. The difficulty facing advocates of xenotransplantation is to be certain of this, because their challenge is to prove a negative.
The potential health risks of infection from xenotransplantation take more than one form. Firstly, there is the possibility of transferring an organism that is not pathogenic to (or perhaps even detectable in) the animal donor …