- "The experts argued in their letter
that this risk (of massive viral epidemics) involves society as a whole
-- and thus society as a whole must first be educated about the risk, and
then consulted about it."
- WASHINGTON (Reuters) - Scientists, some of them top transplant researchers,
called for a moratorium on animal-to-human transplants Wednesday, saying
it was just too dangerous. The main risk is that animal organs, especially
pig organs, could carry viruses that could mutate and cause epidemics across
whole populations, they said.
- Their letter, published in the science
journals Nature and Nature Medicine, coincides with a public hearing being
held by the U.S. National Institutes of Health (NIH), the Food and Drug
Administration (FDA) and other agencies trying to come up with a policy
toward xenotransplants, as they are called.
- More than 55,000 Americans are on the
waiting list for an organ transplant, according to the U.S. Department
of Health and Human Services. But only about 20,000 transplants are done
each year -- mostly due to a shortage of organs -- and so 4,000 people
die every year because organs did not become available in time to save
- ``The demand for human cells, tissues
and organs currently exceeds the available supply,'' Dr. Amy Patterson
of the FDA's Division of Cellular and Gene Therapy, told Wednesday's public
- Several hospitals and private companies
have turned to the possibility of using animal organs for transplants.
But the letter, signed by nine scientists including Harvard Medical School
xenotransplantation researcher, Dr. Fritz Bach and Dr. Harvey Fineberg,
a Harvard public health professor, says there are more important concerns.
- ``Despite the fact that lives of patients
needing transplantation may be lost with delay, we believe that the risks
are sufficient to warrant refraining from human xenotransplantation until
public deliberations on the ethical issues have occurred,'' they wrote.
- They said the public needed to be educated
and then join scientists, ethicists and government regulators in discussing
how to go ahead.
- The biggest public risk comes from viruses.
Pigs are considered the most likely candidates for animal-to-human transplants,
also known as xenotransplants. Their cells are already being injected experimentally
into the brains of people with Huntington's and Parkinson's disease and
into the pancreases of people with diabetes.
- Pigs are similar in size to humans and
are easily bred. But they carry viruses known as porcine endogenous retroviruses.
No one knows if the viruses can pass to humans or if they would cause disease.
- Under the worst scenario, the viruses
would mutate in people and cause epidemics.
- The experts argued in their letter that
this risk involves society as a whole -- and thus society as a whole must
first be educated about the risk, and then consulted about it.
- ``While news reports of breakthroughs
in the use of animal tissue are appearing frequently, many in the lay community
still fear the idea of organ farming and regard the exchange of body parts
between animals and humans as macabre and the stuff of horror films,''
- Transplant recipients, and their sexual
partners, would face lifelong surveillance -- and would have to understand
the implications of this.
- There were also animal welfare issues,
with experimental animals doomed to life in a sterile laboratory. But,
the doctors added, research should be strongly encouraged.