New York  - Researchers in Canada have developed a blood test that could make it possible to detect mad cow disease in animals months before they exhibit symptoms of the illness.

"That would be a great breakthrough because then we would not have to examine the brain of the dead animal, instead we'd have a simple, quick test, similar to a paternity test," German molecular biologist Christoph Sensen of the University of Calgary told Deutsche Presse- Agentur dpa in an interview on Friday.

Researchers examined infected and uninfected elk, since the species develops symptoms of bovine spongiform encephalopathy (BSE) more quickly than cows. They then took monthly blood samples and found specific DNA markers in the infected animals that corresponded to the disease. The tests found evidence of the disease up to six months before symptoms became evident, Sensen said.

Currently, the disease can only be diagnosed by testing the brains of dead animals. The development of a blood test would make the process much cheaper, simpler and reliable, Sensen said.

His team is working with German and Canadian experts to get the test ready for certification. But any test would not be put into widespread use for about four years, because the process must still be tested on enough cows. (dpa)