Mad Cow Disease May Be Transmitted Before Symptoms Appear
Bostock says he does not believe additional precautions need to
be taken to safeguard the blood supply as a result of his findings. But he says
they confirm the earlier measures, including the ban on U.S. blood donations
from certain people.
Paul Brown, PhD, of the laboratory of Central Nervous System
Studies, under the National Institutes of Health, tells WebMD he does not think
these early results from the British research should have been published. He
wrote a commentary accompanying the research paper.
"It doesn't change our fundamental way of thinking about
this disease," Brown says. "Transfusion has been used for transmission
and we know that the blood is infectious. It doesn't change a thing" in
terms of the precautions required for blood donations.
For him, the study's message is limited to its finding that mad
cow disease can be transmitted during the disease's incubation period in an
"experimental model" involving a blood transfusion from one sheep to
another. This does not imply that a sheep could give the disease to a lamb, or
that one sheep could naturally transmit it to another even though it shows no
symptoms, Brown says.
Bostock tells WebMD that he wanted to publish his early results
because he believed they were in the public interest.
"The fact is, this experiment in its entirety would take 10
years to complete," Bostock says. "If we were to keep the work secret,
that we had a positive transmission, we would be in an extremely uncomfortable
"We are also investigating whether [mad cow disease] can be
transmitted between individuals -- either mother to lamb or sheep to
sheep," Bostock adds.
Roger Dodd, PhD, head of transmissible research at the Jerome
Holland Laboratory in Rockville, Md. -- the primary research facility for the
American Red Cross -- tells WebMD that the researchers' finding confirms
expectations. The fact that the sheep developed mad cow disease during the
disease's incubation period was the reason "precautions were put in
place" for blood donations, he notes.
The researchers say that developing a test to diagnose mad cow
disease is among the most important steps in combating the disorder. In the
early 1980s, when little was known about the cause and transmission of AIDS,
the world's blood supply was unprotected against HIV, and some people developed
the disease from transfusions with infected blood. Now tests are run to screen
blood for HIV, but screening of donors is the primary way the blood supply is
Brown calls the association between HIV and mad cow
"unwise," saying the two diseases "are so different." But
Bostock acknowledges that the situation is similar to the days when no tests
were available to detect HIV in the blood supply. Even today, with advanced
testing available to detect HIV, there is a two-week window between the time a
person is infected with HIV and when the disease can be detected in the