CALGARY - A small squirt of blood may soon be enough to confirm the genetic signs of mad cow disease long before an animal begins to show symptoms.
BSE can lurk undetected in a cow for years before the animal suddenly begins to show the disoriented, shaky behaviour that's followed fairly quickly by death.
Right now, the only way to confirm an animal has been infected is by testing its brain after death. That has raised fears an ill animal could go undetected.
But researchers at the University of Calgary say they've figured out how to test the blood of infected animals while they're still alive.
"This could be huge," researcher Christoph Sensen, a professor in the faculty of medicine, said Thursday. "So far all the testing is done on dead animals' brains. And it's very expensive and time-consuming to do it that way."
Researchers first ran tests in elk infected with chronic wasting disease, which is similar to BSE. They scrutinized hundreds of thousands of gene sequences and compared them to the DNA in the blood of healthy elk. Eventually, they found tiny differences that popped up only in the sick animals.
"The smaller the sequence gets that you have to find at the end, the harder it becomes. It's like finding a needle in a haystack," said Sensen.
They've also shown similar changes in the blood of cows with BSE, although they haven't done a study to show how the DNA is altered in an infected animal over time.
A live test could put to rest concerns that have dogged Canadian farmers since the economically devastating 2003 closure of the border with the United States over BSE-contaminated cattle.
Canada brought in changes more than a decade ago to stop animal products from being fed to cattle, sheep and goats and prevent the transfer of BSE into the food chain. That measure appeared to put a virtual stop on the spread of the disease, but some cases still popped up. More safety measures followed and the Canada-U.S. border was fully reopened in 2007.
Fourteen cases have been diagnosed in Canada since 2003, the most recent found in Alberta in August.
"A major loss to the cattle industry in Canada is actually the fact that there (are) continuing cases of BSE in cows," said Sensen. " And this is billions of dollars lost."
He admits that more research needs to be done, including to see whether the blood markers would be the same across different breeds of cattle. Eventually, however, such a live test could provide a "bulletproof" guarantee that Canada's cows are BSE-free.
Other groups across Canada are also working on techniques that could lead to live BSE tests, including a group in Winnipeg investigating the use of urine samples.
