AMES,
Iowa – All 260 Vermont sheep suspected of having been exposed
to a form of mad cow disease have been killed, and tissue samples
were being tested Tuesday at a U.S. Department of Agriculture veterinary
laboratory.
Before the
flocks were sent to Iowa, four sheep tested positive in Vermont
for transmissible spongiform encephalopathy, or TSE, a family
of diseases that includes bovine spongiform encephalopathy (BSE),
or mad cow disease, and scrapie, a common sheep disease that doesn't
affect humans.
Scientists
at the National Veterinary Services Laboratory here said they
were running a series of blood and tissue tests on the carcasses.
They said they would know within two or three months how many
of the sheep were carrying TSE.
The East Friesian
milking sheep, seized from two farms in Vermont, were imported
before an epidemic of mad cow disease prompted a ban on European
livestock in 1997. The animals were thought to have been exposed
to contaminated feed.
An epidemic
of mad cow disease devastated the British beef industry in the
1990s. Nearly 100 people in Europe have died of a human form of
BSE since 1995, but no cases have been confirmed in the United
States.
The USDA also
said Tuesday it was tracking a handful of cattle imported from
Britain before the 1997 ban. None of the animals had shown any
illness, said USDA spokesman Jim Rogers.
"It's
my understanding they are going to be bought and destroyed, but
none of them have ever entered the human or animal food chain,"
said Ed Curlett, a USDA spokesman.
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