It's possible the latest and fourth case of BSE in the United
States is a natural but extremely rare occurrence. Guy
Longeragan, an epidemiologist and food safety expert at Texas
Tech University, said Tuesday afternoon that the "atypical" form
of BSE with which this California dairy cow was diagnosed "could
be a spontaneous and extremely rare event, usually in older
animals." The case was diagnosed with what he called a protein
fingerprint, similar to a DNA analysis. Of the four BSE cases in
this country, only the first one in 2003 was "classical" or
typical BSE, which Longeragan said is known to be spread only
through feed. The next two cases, discovered in 2005 and 2006,
were both atypical cases and both were in beef cattle. So little
is known about the atypical form of BSE that its origin is a
mystery and there appears to be no scientific trail to follow,
he said. BSE has never shown to be contagious to other animals
in either form. Worldwide there have been 180,000 cases of
classical BSE but only just ove