Modified cattle feed may prevent mad cow disease

In the not-so-distant future, Dr. Nat Kav hopes to be in a greenhouse tending a special crop of plants that could inoculate cattle against mad cow disease.

Kav, an associate professor in the University of Alberta agriculture department, says the idea is to give cattle protection against bovine spongiform encepthalopathy by growing antibodies to the disease in plants they eat.

Kav and U of A biochemistry Prof. Michael James are working with Swiss researchers as part of the international effort to understand BSE, a relatively new disease.

Five years ago this weekend, the discovery of a case of BSE on a northern Alberta farm set off a crisis that cost beef producers millions of dollars when the U.S. closed the border to Alberta beef.

Cattle's immune systems do not detect the abnormal protein that causes the disease, so the animals do not produce antibodies to attack the folded protein that eats holes in the brain.

World renowned Swiss scientist Adriano Aguzzi managed to create antibodies to BSE using mice, and Kav and James obtained some of these for this project, Kav explained. Kav is working on transferring them into plants, while James is looking at the structure of the antibodies to see how they prevent the prion from suddenly becoming misshapen.

Their work on this little understood disease is ground-breaking.

"Growing the antibodies in plants is not a problem," says Kav. That kind of transgenic plant (transplanting genetic material from one organism to another) is not difficult. "The question is whether the antibodies will prevent the protein from shifting shape."

In the long run, if the antibody is successful in fighting the rogue prion, the same process could be used to fight Alzheimer's, a related human brain disease, says Kav. "Though I'm dreaming a bit here, " he adds.

In the wake of Canada's BSE crisis, the province set up the Alberta Prion Institute to encourage research into the disease and the federal govement established Prionnet, a new funding agency.

The Alberta Prion Institute is also looking at chronic wasting disease, a BSE-related disease in wild deer populations, says the institute's scientific director Steve Moore.

This spring, Alberta again culled deer in four areas with outbreaks of CWD in the animals near the eastern border. About 1,850 deer were killed last year and at least 1,000 deer will be killed this round.

While BSE is spread through contaminated cattle feed, scientists are still trying to figure out how CWD is spread, whether through urine, feces or touch, says Moore. And whether CWD could transfer to cattle.

Also, it's well known that BSE has been transmitted to humans as variant Creutzfeldt-Jakob disease in Britain, though there are no cases in Canada.

It's not known if CWD can be transmitted to humans, says Moore. Though there have been no recorded cases, that also needs to be studied, says Moore.