A new study by British researchers on the possibility of passing animal viruses to human beings through xenotransplantation (the transplantation of an organ from an animal into a human being) recently led to many news stories highlighting the possible dangers of xenotransplantation. But just how serious is the threat?
In the study by the UK’s Natural Environment Research Council, scientists reported that their studies demonstrated that pig retroviruses that cause cancer spread very easily from species to species in the wild. Obviously if they can spread easily to other animals, they could spread to human beings, possibly creating an epidemic along the lines of what happened when HIV jumped from an animal species to human beings.
Consider how small the risk must be. Human/non-human primate interactions are relatively rare in the bigger scheme of things, and yet HIV quickly jumped from monkeys to human beings and then to a worldwide epidemic once the proper vectors were in place (mainly cheap, fast worldwide transportation). Similarly, human beings have had regular contact with pigs for thousands of years and have paid the price in regular influenza outbreaks, including one in the early 20th century that killed millions of people worldwide.
And yet in all that time with intensive animal agriculture in pigs, not once has there been a reported transmission of a cancer causing retrovirus from swine to human beings. If cancer causing retroviruses could easily pass the species barrier between pigs and human beings, it is very surprising this has not already happened without xenotransplantation.
This is confirmed by the fact that hundreds of people around the world were given xenotransplanted organs and not a single one has ever shown signs of a retrovirus.
Finally, the solution for this is obvious — animals intended for xenotransplantation must be grown in sterile conditions where they don’t have contact with other animals. Of course the primary opponent to that is the very animal rights activists who argue xenotransplantation is too dangerous because diseases could spread from one animal to another and then human beings.
In a story in the UK Observer, George Griffen of the UK Xenotransplantation Interim Regulatory authority wonders, “…if the risk [of spreading a disease] is found to be very, very small, would it be right to block xenotransplants, given that they could help treat so many serious illnesses?” More importantly as the Observer story highlights, if Western nations adopt ridiculously stringent regulations to prevent extremely low or nonexistent levels of risks, the possibility will always exist that such transplants will be carried out in developing nations that lack any sort of serious regulation of the procedure and might pose a much higher risk to humanity of creating an epidemic.
Source:
Cancer peril of animal organ transplants. Robin McKie, The Observer, July 23, 2000.