There is no cure for mad cow disease or its human form, variant Creutzfeldt-Jakob disease (vCJD). No approved therapy slows or stops the disease once symptoms begin. Every treatment attempted so far, from repurposed drugs to experimental antibodies, has failed to change the outcome. Between 1996 and 2023, 233 people worldwide died from vCJD, and the disease has been fatal in every confirmed case.
Why Prion Diseases Resist Treatment
Mad cow disease belongs to a family of illnesses caused by prions, which are not viruses or bacteria. A prion is a normal brain protein that has folded into the wrong shape. Once a single misfolded protein appears, it acts like a template, forcing neighboring healthy proteins to refold into the same abnormal configuration. This chain reaction spreads through the brain, destroying tissue and leaving sponge-like holes visible under a microscope.
This mechanism is what makes prion diseases so difficult to treat. Antibiotics target bacteria. Antivirals target viral replication. But prions are your own proteins gone wrong, and the body’s immune system doesn’t recognize them as foreign invaders. The misfolding process also happens extremely quickly, on a timescale faster than a millisecond at the molecular level, which means by the time symptoms appear the damage is already widespread and irreversible. There is no inflammation to suppress, no pathogen to kill, and no way to undo the structural damage to brain tissue once it has occurred.
Treatments That Have Been Tried
Researchers have tested several repurposed drugs in human patients, including quinacrine (an antimalarial), doxycycline (an antibiotic), pentosan polysulphate (a blood thinner), and flupirtine (a pain reliever with neuroprotective properties). None produced meaningful clinical benefit.
The most notable recent effort involved PRN100, a monoclonal antibody designed to bind directly to the misfolded prion protein. Six patients with Creutzfeldt-Jakob disease received repeated intravenous doses under a special license in the UK. The treatment was well tolerated, and four of the six patients reached the target drug concentration in their cerebrospinal fluid. Despite this, all six showed progressive neurological decline. No evidence of clinical benefit was observed. PRN100 remains the only antibody-based treatment ever given to humans for prion disease.
Gene-Silencing Research in Animals
One of the more promising lines of research involves antisense oligonucleotides (ASOs), which are short synthetic molecules designed to reduce production of the normal prion protein in the brain. The logic is straightforward: mice that are genetically engineered to produce no prion protein cannot develop prion disease, so reducing prion protein levels might slow or prevent the disease in those already exposed.
In laboratory mice infected with prions, an optimized ASO delivered directly into the brain extended the incubation period by almost two months. That result is encouraging in a research context, but the gap between extending survival in mice and curing a human patient is enormous. Whether ASOs can be developed into an effective therapy for people dying of CJD remains an open question, and no human trials of this approach have been completed.
What Happens After Diagnosis
Because no disease-modifying treatment exists, care for vCJD focuses entirely on comfort. Doctors may prescribe antiseizure drugs or muscle relaxants to manage involuntary muscle twitching, and opioids for pain. People with prion disease often become unusually sensitive to touch, loud sounds, and crowded environments, so creating a calm, predictable setting can help reduce agitation.
Diagnosis itself has improved significantly. A test called RT-QuIC can now detect prions in spinal fluid with about 90% sensitivity and 98.5% specificity across all prion diseases. It works by amplifying tiny amounts of misfolded protein in a lab setting, and it became the standard diagnostic tool at the U.S. National Prion Disease Pathology Surveillance Center in 2019. Before this test, definitive diagnosis often required a brain biopsy or could only be confirmed after death.
How the Disease Is Prevented
Since there is no cure, prevention is the primary public health strategy. The U.S. Department of Agriculture tests roughly 25,000 cattle per year, targeting animals most likely to carry the disease: those showing signs of nervous system problems, those unable to walk, and dead or injured cattle. This surveillance level can detect a single case of BSE per million animals in the national herd with 95% confidence.
Two additional safeguards are in place. The FDA banned the use of certain animal-derived ingredients in cattle feed in 1997, which eliminates the main route of transmission between animals. And slaughterhouses are required to remove specified risk materials, the parts of the animal (brain, spinal cord, certain other tissues) most likely to harbor prions, before meat enters the food supply.
Blood donation policies have also evolved. For years, the FDA indefinitely deferred anyone who had spent significant time in the United Kingdom between 1980 and 1996 or received a blood transfusion in the UK, France, or Ireland. Those geographic deferrals have since been removed, and previously deferred individuals can now requalify as donors provided they meet all other eligibility requirements. The change reflects how rare vCJD has become: with only 233 deaths reported worldwide over nearly three decades, the risk no longer justifies excluding millions of potential blood donors.