With the latest case of bovine spongiform encephalopathy (BSE) garnering all kinds of media attention, I thought it might be interesting to turn our attention to some promising research into the disease.
BSE is a rare, fatal, neurodegenerative disease in cattle. Symptoms can include everything from changes in temperament to an inability to stand.
Though there is some evidence to suggest that BSE can result from a mutation within the prion protein gene, it is most commonly spread by feed containing meat and bone meals from infected animals. Infected feed may contain prions (PrPsc
), or disease-causing
forms of cellular prion protein (PrPc
). The pathogenic PrPSc exhibit
abnormal folding, and are able to recruit normal cellular prion proteins to fold in the same manner. Clusters of prions appear as microscopic holes in the brain, giving BSE its “spongy” nature.
There is currently no test to detect BSE in live animals, but recent research has shown promising results in both diagnosis and management.
Much of the research into blood tests have revolved around variant Creutzfeldt-Jakob Disease (vCJD), often referred to as the human form of BSE.
In 2011, a report
out of the Medical Research Council based at Univeristy College London demonstrated that vCJD could be detected in blood at incredibly small levels.
"We have quite a lot of room for improving this test,” John Collinge, director of the MRC prion unit told The Guardian
. "At the moment, a firm diagnosis can usually be made only once serious symptoms of the disease have developed which indicate extensive damage to the brain."
And indeed, that has been the focus of research in the last few years. In June of 2014, French researchers were published
in the journal Plos for work into detecting vCJD in humans and animals during early stages of the disease.
The researchers correctly identified three of four vCJD patients and had no false positives in 114 healthy samples. They used a technology called Protein Misfolding Cyclic Amplification (PMCA), which facilitates protein misfolding in vitro, allowing even minute amounts of prions to be dectable through repetitive cycles of incubation and sonication.
Due to limited availability of blood from patients confirmed positive, the study needs
to expand its sample size before proposing a company develops the test.
Using urine as a source to detect BSE is increasing in research popularity, due in large part to its ease of collection. A 2008 study
showed promising results, demonstrating that biomarkers may be useful in determining a diagnosis and monitoring the progression of the disease.
Studies as recent as 2014
indicate potential in the development of a vaccine. Some scientists are also looking at halting disease progression by exposing prions to molecules that bind to the misfoldings. This could have huge potential for both the bovine and human version of the disease.
Hematech Inc (now owned by Stanford Health) was one of the first to develop cattle resistant to BSE. They genetically engineered a cell line to disable the gene responsible for prion production and used those cells in the cloning of a dozen bulls. Reuters reported
on a similar story out of South Korea.
Our Role Now
Though research into BSE and other transmissible spongiform encephalopathies still has a long way to go, there is some promise in the work thus far. With hope, we will soon have a plethora of better management practices to mitigate the risk of disease spread. For now, adhering to feed bans and participating in surveillance systems seems to be working. Keep it up.
Debra Murphy is a full-time field editor for RealAgriculture, a part-time farm hand and an occasional ranter on the topic of BSE surveillance.