THE mysterious spate of deaths from vCJD, centred on the Leicestershire
village of Queniborough, was caused by prime cuts of meat that were contaminated
as the animals were butchered. That鈥檚 the conclusion of an investigation into
the outbreak, which reported last week.
It has been hailed as the first serious attempt to explain how the BSE agent
gets inside its human victims. If the conclusions are correct, most of the
victims were infected years before the BSE epidemic peaked and incubated the
infection for 10 to 15 years before falling ill. That means it could be several
years before the vCJD epidemic peaks. But hopes that this will be the final word
on the five deaths are quickly evaporating.
Investigators led by Leicestershire health official Phillip Monk interviewed
victims鈥� families and local food suppliers. They found no shared factor
involving vaccines, surgery, blood transfusions, baby food or local schools. But
a strong link with two local butchers did emerge.
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During the 1980s the victims鈥� families were 15 times more likely than
villagers unaffected by the disease to have eaten meat from the two butchers.
Tellingly, both outlets sold meat prepared by traditional methods, now outlawed,
that may have helped infected brain matter spill out and contaminate surfaces
and knives.
Local slaughtermen inserted a rod into the cows鈥� brains to stop them kicking
as they killed them. The two butchers would sometimes take the pierced heads and
split them open to remove the brains, for which there was still a small market.
Such methods were legal in Britain until 1989.
One alarming conclusion is that the amount of BSE-tainted material needed to
infect people must be lower than anyone thought. Experts assumed eating burgers
or sausages containing scraps of infected brain or spinal cord would be the
likeliest way of getting an infective dose. The Queniborough report blames
steaks and joints accidentally splashed with infected material.
But researchers are now questioning the cross-contamination theory. 鈥淚t
wasn鈥檛 milligrams on the knife, it was kilograms of brain and spinal cord鈥� being
added to sausage meat or mince, says Jean-Philippe Deslys, a prion disease
expert at the French Atomic Energy Commission鈥檚 medical laboratory in
Fontenay-aux-Roses. Across Britain people were getting traces of brain and
spinal cord in mechanically recovered meat and other sources, he says. The
Queniborough victims must have received more infection to stand out.
The investigators firmly reject this idea. 鈥淧eople who worked with the
butchers deny ever using spinal cord or brain to make mince or sausages,鈥� says
Monk. 鈥淭he crucial factor was the removal of brains.鈥� Another problem for the
cross-contamination theory is that head splitting was practised at small
abattoirs and butchers across Britain during the 1980s. So why only one cluster
in one village?
It鈥檚 because the incubation period is so long that the other clusters have
yet to show themselves, says Monk. Queniborough, he believes, is just the first
of many outbreaks that will in time be linked to the practice of head splitting.
The study, he says, is 鈥渆xtremely bad news鈥�.