The mice infected with scrapie -- a brain-wasting disease of sheep -- showed high levels of the scrapie agent in their hearts several hundred days after their brains were infected, indicating heart infection might be a new aspect of the disease.
Collaborators in the work included scientists at the Rocky Mountain Laboratories, part of the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health.
"Although much work remains to be done, the diseased hearts seen in this mouse study have similarities to human amyloid heart disease, which is potentially significant," said NIAID Director Anthony Fauci.
Scrapie belongs to a group of diseases also known as transmissible spongiform encephalopathies because of the sponge-like holes created in the brain.
In addition to scrapie, prion diseases include Creutzfeldt-Jacob disease in humans, mad cow disease in cattle and chronic wasting disease in deer and elk. Researchers said the cause of prion diseases, still under debate, might be abnormal aggregated forms of prion protein.
The research appears in the journal Science.