How now, mad cow?

>> The trouble with Quebec's itchy sheep

by RINA CALABRESE and GEORGE MADDUX

West Brome Lake farmer Leslie Sayers has seen the Quebec sheep plague from up close. A few years ago he'd often spot the wooly beasts on a neighbouring farm with huge sores on their backsides, weak and hardly able to stand.

"They'd have spots, maybe five or six inches square, where there's no wool," he says. "They scratched it all off and it was just raw sores." The animal authorities killed off the ones that didn't die. Since 1997, almost 300 Quebec farmers have been ordered to destroy more than 12,000 sheep feared to be carrying the disease called scrapie. Barns were washed down and disinfected.

The fatal neurodegenerative sheep disease is caused by a protein called a prion that, for a reason nobody understands, sometimes morphs into tiny particles that can survive boiling water, chemical disinfectants or strong radiation. Prions have been linked to mad cow disease (BSE) and its human equivalent, Creutzfelt-Jakob disease (CJD), a fatal illness that causes the brain to degenerate into a sponge-like form.

Many scientists believe that humans first contracted CJD by eating beef fed on scrapie-contaminated sheep tissue. Yet in spite of the energetic government response to sheep scrapie, Health Canada insists that the shivering sheep pose no risk to humans.

But a collection of articles reprinted from major newspapers at the Web site www.mad-cow.org portrays the troubling, near-daily surprises that scientists have uncovered concerning CJD transmission. For example, scientists have learnt that prions can survive on sterilized surgical instruments and have infected surgical patients with CJD. Another example of the widespread concern is that American wildlife officials now worry that a similar CJD-type epidemic could start in the United States, spread by infected deer and elk.

Scientists are currently investigating the most troubling aspect of sheep scrapie--the potential for sheep getting infected with the bovine variety of the ailment (BSE), which would make a new breed of mad sheep impossible to differentiate from those afflicted with scrapie.

But Canadian officials maintain that Quebec's current scrapie epidemic will have no negative health effects on humans. "There's absolutely no indication that scrapie could be transmissible to humans," says Claude Lavigne, deputy director of the animal health and production division at the Canadian Food Inspection Agency in Ottawa. However, Lavigne admits that there is currently no existing test that can be performed on live sheep to determine whether they are carrying scrapie.

So is it safe to eat Quebec lamb? Genevieve Rousseau, a veterinarian for the Quebec Ministry of Agriculture says, "I wouldn't eat an animal that showed signs of scrapie but if somebody said 'Don't eat lamb anymore,' I'd think the opposite. The fact that the [contaminated] animals were killed shows that in Quebec it's actually safer."

But while the blood of butchered sheep flows, Quebec's blood agency is stemming its own blood supply to protect against a CJD epidemic. Last year Héma-Québec stopped accepting blood from donors who had spent more than one month in the U.K. from 1980-1996. And as of October 30, anyone who has visited France for six months from 1980-1996 is also barred.

Although CJD has been transmitted through blood elsewhere and no screening process exists to detect the disease in the blood supply, Héma-Québec, in announcing the new donor restrictions, described any risks of CJD transmission through blood as "theoretical." :

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