BSE test for live animals researched

Cattle Market & Farm Reports, Editorials
Mar 14, 2005
by WLJ
A team of scientists at Hokkaido University is developing an automated device to detect BSE using blood samples from live cattle, according to the Japanese press.
The team, led by Mamoru Tamura, a professor at the Research Institute for Electronic Science at the university, hopes to develop the device by this summer.
Detecting BSE in young cattle has been thought to be difficult because the type of protein found in the brain of infected cows, prion, accumulates as the animals age.
The scientists said the new device will pave the way for establishing a faster and more accurate testing method for the disease, formally known as bovine spongiform encephalopathy.
Under the current system, Japan tests all cows for BSE by taking brain tissue samples when animals are slaughtered.
A method called ELISA, or Enzyme-Linked Immunosorbent Assay, is used for the initial test before government agencies verify the results during a second-phase test.
The ELISA involves adding enzymes to brain tissue samples but requires some manual work and takes four to five hours to produce results. In addition, it sometimes mixes up negative cases with suspected ones.
The method being developed by the Hokkaido team is done by adding prion antibodies and fluorescent dye to blood samples. The team then irradiates the samples with a laser to measure how fast the dyed antibody molecules move.
The fully automated testing quantifies the speed of the molecules’ movements and displays it on a monitor. The team says prion, when combined with antibodies, is likely to grow into larger molecules and moves slower than the lighter, normal molecules.
The test takes no longer than 90 minutes to produce results and is about 10 times more sensitive than the ELISA method, the team says.
The team plans to make the device small, so cattle breeders can easily use it on the farm.
Detecting BSE in cows younger than 20 months old was thought to be difficult. “But with the new device, we can detect BSE regardless of a cow’s age,” research team leader Tamura said.
“It would be a groundbreaking achievement if the device can help prevent the spread of BSE by detecting the disease in live animals,” said Yoshio Yamakawa of the National Institute of Infectious Diseases in Tokyo. “But the team may need to work on enhancing the sensitivity of the test because an amount of prion in the blood is very small.” — WLJ