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Emerging Infectious Diseases
Volume 2, Number 2, April-June 1996

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Letters

The Dilemma of Xenotransplantation

To the Editor:

I read with considerable interest Robert E. Michler’s commentary on
xenotransplantation (1).

From my point of view, that of a basic virologist, the dilemma is not to
know in what “foreseeable future, clinical xenotransplantation may achieve
its targeted goal of extended graft survival, but what deadly emerging
infectious disease, most probably viral in nature, would arise in a
recipient of a baboon or chimpanzee heart. While we face the terrific
threat of AIDS, which clearly emerged from Africa and non-human primates 40
to 50 years ago, we are preparing a new infectious Chernobyl.

Monkeys and apes harbor approximately 50 simian viruses; some of them pose
a serious threat to humans, especially the heavily immunosuppressed.
Recently, an outbreak of encephalitis related to a new type of reovirus (2)
occurred among baboons from a colony used in human organ transplants.
Moreover, once unknown or unrecognized simian viruses, like HIV, may be
efficient invaders of the entire earth’s population.

Xenotransplantation does not simply pose an ethical problem; it concerns
the survival of the human species, an endangered species if transplant
practitioners continue their course. Ronald Montalero, a virologist, was
right when he said “unknown viruses were always a major concern in
xenotransplants (2). A moratorium on these procedures seems the best
solution until all simian pathogens are identified and the risks they pose
to humans are clearly established.

Claude E. Chastel
Virus Laboratory, Faculty of Medicine
29285 Brest Cedex, France

References

1. Michler RE. Xenotransplantation: risks, clinical potential, and future
prospects. Emerging Infectious Diseases 1996; 2; 64-70.

2. Mystery virus fells donor baboons. Science 1994; 264; 1523.