Blood Transfusion Blamed for Second 'Mad Cow' Infection in Humans

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This is Gwen Outen with the VOA Special English Health Report.

Blood transfusions can save lives. But they can also spread
diseases. Researchers believe this is how at least two people in
Britain became infected with the human version of mad cow disease.
They say the cases appears to confirm that eating beef from an
infected cow is not the only way the disease can spread.

The first case was reported at the end of last year; the second
was reported earlier this month in the magazine The Lancet. The
second patient had received a blood transfusion five years ago. The
unidentified person was one of seventeen known to have received
blood from people who later developed vCJD. The full name is variant
Creutzfeldt-Jakob disease.

The disease attacks the brain and central nervous system. But in
this patient, the infection had not spread to those areas. In fact,
the report says the elderly person never developed signs of the
disease. The patient died of unrelated causes. Tests later found the
infection in the spleen.

Scientists say the finding suggests that a larger population of
people could become infected. And here is why:

The human genetic map comes in different versions called
genotypes. This patient had the most common genotype in the British
population. One hundred fifty deaths from the human form of mad cow
disease have been reported worldwide. But so far, there have been no
such cases in people with this common genotype.

James Ironside is an investigator with the CJD Surveillance Unit
in Edinburgh. He says infections might take longer to appear in
people with this genotype.

The evidence also suggests that people without signs of the
disease could still carry the infection. And they may be able to
pass it to others.

In cows, the official name of the disease is bovine spongiform
encephalopathy. Holes form in the brain. Researchers say the disease
is caused by prions, proteins that are deformed and infectious. No
cure is known. But French scientists reported in The Lancet that
they have identified a new way to clean prions off of medical

Also, American scientists reported on a method used in Britain to
try to make blood safer for transfusion. White blood cells are
removed to lower the risk of the human form of mad cow disease. But
the researchers say animal tests found that the risk is reduced by
only about forty percent.

This VOA Special English Health Report was written by Cynthia
Kirk. This is Gwen Outen.