Prion diseases, also known as transmissible spongiform encephalopathies or TSEs, are a group of rare, fatal brain diseases that affect animals and humans. They are caused by an infectious agent known as a prion, which is derived from a misfolded version of a normal host protein known as prion protein. Prion diseases include bovine spongiform encephalopathy (BSE or "mad cow" disease) in cattle, Creutzfeldt-Jakob disease (CJD) and variant CJD in humans, scrapie in sheep, and chronic wasting disease (CWD) in deer, elk, moose and reindeer.
Why Is the Study of Prion Diseases a Priority for NIAID?
Prion diseases are a significant public health concern and have been known to spread from animals to people and, in the case of variant Creutzfeldt-Jakob disease, from human to human through blood. Prion diseases in people are difficult to diagnose and, when they are diagnosed, there are no effective treatments available. As a result, they are inevitably fatal. However, much about prion diseases remains unknown and understanding how they work is important for the development of both diagnostic tests and effective therapies. Prion diseases also are related to other protein misfolding diseases such as Alzheimer’s disease, Parkinson’s disease, and Lewy body dementia. Prion diseases also are related to diseases involving misfolding of the tau protein, including chronic traumatic encephalopathy (CTE), which is associated with brain damage from repeated head injuries. Thus, research into prion diseases also can help scientists better understand other related diseases.
How Is NIAID Addressing This Critical Topic?
NIAID scientists are examining how prion diseases develop and spread between people and animals, how they can be diagnosed, and how they can be treated. NIAID conducts prion disease research at its Rocky Mountain Laboratories in Hamilton, Montana, and also funds prion disease research in university labs. NIAID collaborations with other NIH groups studying aging disorders and neurological diseases also are important. Two other Institutes at the National Institutes of Health also fund prion disease research—the National Institute of Neurological Disorders and Stroke and the National Institute on Aging.
To learn about risk factors for prion diseases and current prevention and treatment strategies visit the Centers for Diseases Control and Prevention (CDC) prion diseases site.
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Biology & Genetics
Prion diseases are associated with the prion protein, which is found in many body tissues, including the brain. Normally, prion protein does not cause disease and resides on the surface of many cell types. Though under investigation, scientists think normal prion protein might help protect the brain from damage. They do know that when many normal prion protein molecules change their shape and clump together, they can aggregate in brain tissue and form the infectious prions that cause prion disease. Prion diseases are therefore caused by an infectious, abnormally shaped and aggregated prion protein. Scientists are not sure why normal prion protein become misshapen. NIAID scientists co-discovered the prion protein gene and were among the first to show that abnormal prion protein can change normal prion protein to the abnormal, infectious form.
Although there are no known ways to cure prion diseases, scientists around the world are working to develop treatments and diagnostics. NIAID researchers have developed a rapid diagnostic test for prion diseases. Using test-tube or cell-based models of prion infection for fast initial screening, NIAID researchers also have tested thousands of compounds and identified hundreds of molecules that inhibit the formation of the abnormal, infectious form of prion protein. Further testing of the most potent of these inhibitors has revealed several that can prolong the lives of rodents even if treatment begins after infection.
Animal Prion Diseases and Humans
There are 3 major prion diseases in animals: scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and chronic wasting disease (CWD) in deer, elk and other cervids. NIAID scientists use various experimental models to study how prions from one animal species can infect different animal species. These include studies to determine whether animal diseases such as CWD can infect people and cause Creutzfeldt-Jakob disease (CJD).