The researchers collected 140 eyeballs from 73 sheep. Thirty five of those sheep were infected with scrapie; 38 were not. The researchers took fluorescence readings from various parts of the eyes of all the sheep.
"The bottom line is the scrapie-positive retinas fluoresced like crazy," Petrich said. "And the scrapie-negative ones did not."
A previous study published in the journal Veterinary Pathology reported that the function and structure of retinas are altered in cattle infected with transmissible mink encephalopathy. Members of that study team included Iowa State researchers M. Heather West Greenlee, an associate professor of biomedical sciences in the College of Veterinary Medicine; Justin Greenlee, a collaborator assistant professor of biomedical sciences; and Juergen Richt, a collaborator associate professor of veterinary microbiology and preventive medicine.
Other studies have reported that lipofuscin, an intracellular fluorescent pigment, accumulates in the eyes of animals infected with the neurological diseases. Petrich and his team attribute the glow from scrapie-positive retinas to the elevated levels of lipofuscin.
Whatever the cause, Petrich said it's clear there are distinct differences in the fluorescence and spectroscopic signatures of retinas from sheep that were naturally infected with scrapie and those that were not. And so he and his research team think there's great promise for a diagnos
|Contact: Jacob Petrich|
Iowa State University