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Cattle urine may lead to live BSE test

Canadian researchers say levels of a telltale protein in cattle urine may be the path to a BSE test for live cattle.

Scientists at the Public Health Agency of Canada’s National Microbiology Laboratory (NML), working with others from the Canadian Food Inspection Agency (CFIA), the University of Manitoba and Germany’s Federal Research Institute of Animal Health report that changed levels of this protein indicate the presence of bovine spongiform encephalopathy (BSE) with “100 per cent accuracy,” albeit in a small sample set.

Changes in the “relative abundance” of a certain set of proteins were also found to correspond with the advancement of the brain-wasting cattle disease, the Winnipeg-based NML said in a release Friday.

“We are hopeful that at some point in the future the knowledge gained from this study will make it possible to test live cattle,” said Dr. David Knox, NML scientist and lead researcher on the study, in the release.

Accurate diagnostic BSE tests for live cattle would be a boon for the Canadian beef industry, which currently must remove and dispose of specified risk materials (SRMs) in all slaughter cattle. SRMs include all tissues that are known to harbour the misfolded proteins, or prions, that cause BSE.

Currently, the only reliable testing methods for BSE in cattle are post-mortem.

“This is an important discovery and we are hopeful that it will eventually lead to a useful diagnostic test that will simplify surveillance and reduce costs,” said Stefanie Czub, manager of the virology section and quality assurance at CFIA, in Friday’s release.

With this finding, “it also may be possible to develop similar tests for other transmissible spongiform encephalopathies (TSEs) in other species, including humans,” Knox added.

TSEs apart from BSE (commonly called mad cow disease) include scrapie in sheep, chronic wasting disease in cervids and Creutzfeldt-Jakob disease (CJD) in humans. A variant of CJD in people is believed to be caused by beef that contains BSE prions.

There are about 30 cases of “classical” CJD (that is, not linked to beef consumption) in people every year in Canada, the NML said. A urine test could help doctors provide potential diagnoses for people suffering dementia of unknown cause.

The scientists, whose findings are now published in the journal Proteome Science, analyzed the proteins in urine samples taken from four infected and four healthy cows of the same age, over the course of the disease.

Their finding that disease progression could be monitored based on changes in the abundance of a set of proteins could have applications for the assessment of potential treatments, the NML said.

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