At the moment only examination of brain issue through a risky biopsy can determine whether someone has Creutzfeldt-Jakob Disease – otherwise known as 'Mad Cow disease'.
But now scientists from the University of Melbourne say they are a step closer to developing a simple blood test that can detect its presence.
Using newly available genetic sequencing scientists discovered cells infected with prions - the infectious agent responsible for these diseases - release particles that contain easily recognised “signature genes”.
Associate Professor Andrew Hill said these particles travel in the blood stream, making a diagnostic blood test a possibility.
The researchers’ genetic testing focused on a form of cell discharge called exosomes.
If exosomes were infected with prions they were found to also carry a specific signature of small genes called microRNA’s.
Professor Hill said: "This might provide a way to screen people who have spent time in the UK, who currently face restrictions on their ability to donate blood.
"With a simple blood test nurses could deem a prospective donor’s blood as healthy, with the potential to significantly boost critical blood stocks."
Mad Cow disease was linked to the deaths of nearly 200 people in Great Britain who consumed meat from infected animals in the late 1980s.
Since 2000, the Australia Red Cross Blood Service has not accepted blood from anybody who lived in the UK for more than six months between 1980 and 1996, or who received a blood transfusion in the UK after 1980.
Lead author Dr Shayne Bellingham said the breakthrough might also help detect other human neurodegenerative diseases, such as Alzheimer’s and Parkinson’s.
“This is an exciting new field where we can test for conditions in the brain and throughout the body, without being invasive,” he said.
Professor Chris Grant, from the University of Manchester's Faculty of Life Sciences, told The Huffington Post UK: "Prion diseases like Mad Cow Disease and variant Creutzfeldt-Jakob Disease pose a serious threat to public health, as symptoms develop only after a long period of infection and infection can only be confirmed definitively by post-mortem examination of the brain.
"The researchers show that affected nerve cells in the brain release a molecular signature that differs from those released by normal healthy cells. This is exciting because it moves us closer to being able to detect infection earlier with a simple blood test and reduce the risk of disease transmission from blood transfusions and organ donations.
"This may ultimately provide us with a simple non-invasive tool for understanding the pathology of neurodegenerative diseases and, potentially, being able to differentially diagnose the different neurodegenerative disorders."
The research is published in this week’s Oxford University Press Nucleic Acids Research journal.
There are four main types of Creutzfeldt-Jakob Disease, with sufferers experiencing progressive dementias and eventually death.