As of 2015 there was no cure for CJD; some of the symptoms like twitching can be managed but otherwise treatment is palliative care.

As of 2017, there was no cure for BSE; some of the symptoms like twitching can be managed but otherwise treatment is palliative care.

There is no cure for GSS, nor is there any known treatment to slow the progression of the disease. However, therapies and medication are aimed at treating or slowing down the effects of the symptoms. Their goal is to try to improve the patient's quality of life as much as possible. Despite there being no cure for GSS, it is possible to undergo testing for the presence of the underlying genetic mutation. Testing for GSS involves a blood and DNA examination in order to attempt to detect the mutated gene at certain codons. If the genetic mutation is present, the patient will eventually be afflicted by GSS, and, due to the genetic nature of the disease, the offspring of the patient are predisposed to a higher risk of inheriting the mutation.

An experimental treatment was given to a Northern Irish teenager, Jonathan Simms, beginning in January 2003. The medication, called pentosan polysulphate (PPS) and used to treat interstitial cystitis, is infused into the patient's lateral ventricle within the brain. PPS does not seem to stop the disease from progressing, and both brain function and tissue continue to be lost. However, the treatment is alleged to slow the progression of the otherwise untreatable disease, and may have contributed to the longer than expected survival of the seven patients studied. Simms died in 2011. The CJD Therapy Advisory Group to the UK Health Departments advises that data are not sufficient to support claims that pentosan polysulphate is an effective treatment and suggests that further research in animal models is appropriate. A 2007 review of the treatment of 26 patients with PPS finds no proof of efficacy because of the lack of accepted objective criteria.

Scientists have investigated using RNA interference to slow the progression of scrapie in mice. The RNA blocks production of the protein that the CJD process transforms into prions. This research is unlikely to lead to a human therapy for many years.

Both amphotericin B and doxorubicin have been investigated as potentially effective against CJD, but as yet there is no strong evidence that either drug is effective in stopping the disease. Further study has been taken with other medical drugs, but none are effective. However, anticonvulsants and anxiolytic agents, such as valproate or a benzodiazepine, may be administered to relieve associated symptoms.

Scientists from the University of California, San Francisco are currently running a treatment trial for sporadic CJD using quinacrine, a medicine originally created for malaria. Pilot studies showed quinacrine permanently cleared abnormal prion proteins from cell cultures, but results have not yet been published on their clinical study. The efficacy of quinacrine was also assessed in a rigorous clinical trial in the UK and the results were published in Lancet Neurology,

and concluded that quinacrine had no measurable effect on the clinical course of CJD.

In a 2013 paper published in the Proceedings of the National Academy of Sciences, scientists from The Scripps Research Institute reported that Astemizole, a medication approved for human use, has been found to have anti-prion activity and may lead to a treatment for Creutzfeldt–Jakob disease.

There is no cure or treatment for GSS. It can, however, be identified through genetic testing. GSS is the slowest to progress among human prion diseases. Duration of illness can range from 3 months to 13 years, with an average duration of 5 or 6 years.

A ban on feeding meat and bone meal to cattle has resulted in a strong reduction in cases in countries where the disease was present. In disease-free countries, control relies on import control, feeding regulations, and surveillance measures.

In UK and US slaughterhouses, the brain, spinal cord, trigeminal ganglia, intestines, eyes, and tonsils from cattle are classified as specified risk materials, and must be disposed of appropriately.

An enhanced BSE-related feed ban is in effect in both the United States and Canada to help improve prevention and elimination of BSE.

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of progressive, invariably fatal, conditions that affect the brain (encephalopathies) and nervous system of many animals, including humans. According to the most widespread hypothesis, they are transmitted by prions, though some other data suggest an involvement of a "Spiroplasma" infection. Mental and physical abilities deteriorate and myriad tiny holes appear in the cortex causing it to appear like a sponge (hence spongiform) when brain tissue obtained at autopsy is examined under a microscope. The disorders cause impairment of brain function, including memory changes, personality changes and problems with movement that worsen chronically.

Prion diseases of humans include Creutzfeldt–Jakob disease—which has four main forms, the sporadic (sCJD), the hereditary/familiar (fCJD), the iatrogenic (iCJD) and the variant form (vCJD)—Gerstmann–Sträussler–Scheinker syndrome, fatal familial insomnia, kuru, and the recently discovered variably protease-sensitive prionopathy. These conditions form a spectrum of diseases with overlapping signs and symptoms. TSEs in non-human mammals include scrapie in sheep, bovine spongiform encephalopathy (BSE)—popularly known as 'mad cow's disease'—in cattle and chronic wasting disease (CWD) in deer and elk. The variant form of Creutzfeldt–Jakob disease is caused by exposure to bovine spongiform encephalopathy prions.

Unlike other kinds of infectious disease, which are spread by agents with a DNA or RNA genome (such as virus or bacteria), the infectious agent in TSEs is believed to be a prion, thus being composed solely of protein material. Misshapen prion proteins carry the disease between individuals and cause deterioration of the brain. TSEs are unique diseases in that their aetiology may be genetic, sporadic, or infectious via ingestion of infected foodstuffs and via iatrogenic means (e.g., blood transfusion). Most TSEs are sporadic and occur in an animal with no prion protein mutation. Inherited TSE occurs in animals carrying a rare mutant prion allele, which expresses prion proteins that contort by themselves into the disease-causing conformation. Transmission occurs when healthy animals consume tainted tissues from others with the disease. In the 1980s and 1990s, bovine spongiform encephalopathy (BSE) spread in cattle in an epidemic fashion. This occurred because cattle were fed the processed remains of other cattle, a practice now banned in many countries. In turn, consumption (by humans) of bovine-derived foodstuff which contained prion-contaminated tissues resulted in an outbreak of the variant form of Creutzfeldt–Jakob disease in the 1990s and 2000s.

Prions cannot be transmitted through the air or through touching or most other forms of casual contact. However, they may be transmitted through contact with infected tissue, body fluids, or contaminated medical instruments. Normal sterilization procedures such as boiling or irradiating materials fail to render prions non-infective.

Variant Creutzfeldt–Jakob disease (vCJD) or new variant Creutzfeldt–Jakob disease (nvCJD) is a transmissible spongiform encephalopathy which was identified in 1996 by the National CJD Surveillance Unit in Edinburgh, Scotland. It is always fatal and is caused by prions, which are mis-folded proteins. Over 170 cases of vCJD have been recorded in the United Kingdom, and around 30 cases in the rest of the world. The fact that the epidemiology of the disease coincided with an epidemic of bovine spongiform encephalopathy led to the hypothesis that consumption of BSE-infected beef caused the disease. It is a different disease from Sporadic and Familial Creutzfeldt–Jakob disease, though it is believed to be caused by the same pathogenic agent, a mis-folded protein, known as a prion.

Despite the consumption of contaminated beef in the UK being reckoned to be quite high, vCJD has infected a comparatively small cohort of people. One explanation for this can be found in the genetics of patients with the disease. The human PRNP protein which is subverted in prion disease can occur with either methionine or valine at amino acid 129, without any apparent difference in normal function. Of the overall Caucasian population, about 40% have two methionine-containing alleles, 10% have two valine-containing alleles, and the other 50% are heterozygous at this position. Only a single vCJD patient tested was found to be heterozygous; most of those affected had two copies of the methionine-containing form. Additionally, for unknown reasons, those affected are generally under the age of 40. It is not yet known whether those unaffected are actually immune or only have a longer incubation period until symptoms appear.

The degenerative tissue damage caused by human prion diseases (CJD, GSS, and kuru) is characterised by four features: spongiform change, neuronal loss, astrocytosis, and amyloid plaque formation. These features are shared with prion diseases in animals, and the recognition of these similarities prompted the first attempts to transmit a human prion disease (kuru) to a primate in 1966, followed by CJD in 1968 and GSS in 1981. These neuropathological features have formed the basis of the histological diagnosis of human prion diseases for many years, although it was recognized that these changes are enormously variable both from case to case and within the central nervous system in individual cases.

The clinical signs in humans vary, but commonly include personality changes, psychiatric problems such as depression, lack of coordination, and/or an unsteady gait (ataxia). Patients also may experience involuntary jerking movements called myoclonus, unusual sensations, insomnia, confusion, or memory problems. In the later stages of the disease, patients have severe mental impairment (dementia) and lose the ability to move or speak.

Early neuropathological reports on human prion diseases suffered from a confusion of nomenclature, in which the significance of the diagnostic feature of spongiform change was occasionally overlooked. The subsequent demonstration that human prion diseases were transmissible reinforced the importance of spongiform change as a diagnostic feature, reflected in the use of the term "spongiform encephalopathy" for this group of disorders.

Prions appear to be most infectious when in direct contact with affected tissues. For example, Creutzfeldt–Jakob disease has been transmitted to patients taking injections of growth hormone harvested from human pituitary glands, from cadaver dura allografts and from instruments used for brain surgery (Brown, 2000) (prions can survive the "autoclave" sterilization process used for most surgical instruments). It is also believed that dietary consumption of affected animals can cause prions to accumulate slowly, especially when cannibalism or similar practices allow the proteins to accumulate over more than one generation. An example is kuru, which reached epidemic proportions in the mid-20th century in the Fore people of Papua New Guinea, who used to consume their dead as a funerary ritual. Laws in developed countries now ban the use of rendered ruminant proteins in ruminant feed as a precaution against the spread of prion infection in cattle and other ruminants.

There exist evidence that prion diseases may be transmissible by the airborne route.

Note that not all encephalopathies are caused by prions, as in the cases of PML (caused by the JC virus), CADASIL (caused by abnormal NOTCH3 protein activity), and Krabbe disease (caused by a deficiency of the enzyme galactosylceramidase). Progressive Spongiform Leukoencephalopathy (PSL)—which is a spongiform encephalopathy—is also probably not caused by a prion, although the adulterant that causes it among heroin smokers has not yet been identified. This, combined with the highly variable nature of prion disease pathology, is why a prion disease cannot be diagnosed based solely on a patient's symptoms.

A slow virus is a virus, or a viruslike agent, etiologically associated with a disease, having a long incubation period of months to years and then a gradual onset of symptoms which progress slowly but irreversibly and terminate in a severe compromised state or, more commonly, death.

A slow virus disease is a disease that, after an extended period of latency, follows a slow, progressive course spanning months to years, frequently involving the central nervous system and ultimately leading to death. Examples include the Visna-Maedi virus, in the genus Lentivirus (family Retroviridae), that causes encephalitis and chronic pneumonitis in sheep, and subacute sclerosing panencephalitis which is apparently caused by the measles virus, as well as Paget's Disease of Bone (Osteitis Deformans) which is associated with paramyxoviridae, especially RSV and Rubeola (Measles).

When infection attacks the body, "anti-infective" drugs can suppress the infection. Several broad types of anti-infective drugs exist, depending on the type of organism targeted; they include antibacterial (antibiotic; including antitubercular), antiviral, antifungal and antiparasitic (including antiprotozoal and antihelminthic) agents. Depending on the severity and the type of infection, the antibiotic may be given by mouth or by injection, or may be applied topically. Severe infections of the brain are usually treated with intravenous antibiotics. Sometimes, multiple antibiotics are used in case there is resistance to one antibiotic. Antibiotics only work for bacteria and do not affect viruses. Antibiotics work by slowing down the multiplication of bacteria or killing the bacteria. The most common classes of antibiotics used in medicine include penicillin, cephalosporins, aminoglycosides, macrolides, quinolones and tetracyclines.

Not all infections require treatment, and for many self-limiting infections the treatment may cause more side-effects than benefits. Antimicrobial stewardship is the concept that healthcare providers should treat an infection with an antimicrobial that specifically works well for the target pathogen for the shortest amount of time and to only treat when there is a known or highly suspected pathogen that will respond to the medication.

Ataxia usually goes away without any treatment. In cases where an underlying cause is identified, your doctor will treat the underlying cause. In extremely rare cases, you may have continuing and disabling symptoms. Treatment includes corticosteroids, Intravenous immunoglobulin, or plasma exchange therapy. Drug treatment to improve muscle coordination has a low success rate. However, the following drugs may be prescribed: clonazepam, amantadine, gabapentin, or buspirone. Occupational or physical therapy may also alleviate lack of coordination. Changes to diet and nutritional supplements may also help. Treatment will depend on the cause. If the acute cerebellar ataxia is due to bleeding, surgery may be needed. For a stroke, medication to thin the blood can be given. Infections may need to be treated with antibiotics. Steroids may be needed for swelling (inflammation) of the cerebellum (such as from multiple sclerosis). Cerebellar ataxia caused by a recent viral infection may not need treatment.

Kuru is a very rare, incurable neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea. Kuru is caused by the transmission of abnormally folded prion proteins, which leads to symptoms such as tremors, loss of coordination, and neurodegeneration.

The term kuru derives from the Fore word kuria or guria ("to shake"), due to the body tremors that are a classic symptom of the disease and kúru itself means "trembling". It is also known as the "laughing sickness" due to the pathologic bursts of laughter which are a symptom of the disease. It is now widely accepted that kuru was transmitted among members of the Fore tribe of Papua New Guinea via funerary cannibalism. Deceased family members were traditionally cooked and eaten, which was thought to help free the spirit of the dead. Females and children usually consumed the brain, the organ in which infectious prions were most concentrated, thus allowing for transmission of kuru. The disease was therefore more prevalent among women and children.

While the Fore people stopped eating human meat in the early 1960's, when it was first speculated to be transmitted via endocannibalism, the disease lingered due to kuru’s long incubation period of anywhere from 10 to over 50 years. The epidemic declined sharply after discarding cannibalism, from 200 deaths per year in 1957 to 1 or no deaths annually in 2005, with sources disagreeing on whether the last known kuru victim died in 2005 or 2009.

It is expected that there will be no new cases of progressive inflammatory neuropathy since the process of aerosolizing the pig brains has been discontinued at all pork processing facilities.

Every infectious agent is different, but in general, slow viruses:

Additionally, the immune system seems to plays a limited role, or no role, in protection from these slow viruses. This may be in part because the host has acclimated to the virus, or more likely because the host must be immunocompromised in order for many of these slow virus infections to emerge, so the immune system is at a disadvantage from the start.

No medications have been shown to prevent or cure dementia. Medications may be used to treat the behavioural and cognitive symptoms but have no effect on the underlying disease process.

Acetylcholinesterase inhibitors, such as donepezil, may be useful for Alzheimer disease and dementia in Parkinson's, DLB, or vascular dementia. The quality of the evidence however is poor and the benefit is small. No difference has been shown between the agents in this family. In a minority of people side effects include a slow heart rate and fainting.

As assessment for an underlying cause of the behavior is a needed before prescribing antipsychotic medication for symptoms of dementia. Antipsychotic drugs should be used to treat dementia only if non-drug therapies have not worked, and the person's actions threaten themselves or others. Aggressive behavior changes are sometimes the result of other solvable problems, that could make treatment with antipsychotics unnecessary. Because people with dementia can be aggressive, resistant to their treatment, and otherwise disruptive, sometimes antipsychotic drugs are considered as a therapy in response. These drugs have risky adverse effects, including increasing the patient's chance of stroke and death. Generally, stopping antipsychotics for people with dementia does not cause problems, even in those who have been on them a long time.

N-methyl-D-aspartate (NMDA) receptor blockers such as memantine may be of benefit but the evidence is less conclusive than for AChEIs. Due to their differing mechanisms of action memantine and acetylcholinesterase inhibitors can be used in combination however the benefit is slight.

While depression is frequently associated with dementia, selective serotonin reuptake inhibitors (SSRIs) do not appear to affect outcomes.

The use of medications to alleviate sleep disturbances that people with dementia often experience has not been well researched, even for medications that are commonly prescribed. In 2012 the American Geriatrics Society recommended that benzodiazepines such as diazepam, and non-benzodiazepine hypnotics, be avoided for people with dementia due to the risks of increased cognitive impairment and falls. Additionally, there is little evidence for the effectiveness of benzodiazepines in this population. There is no clear evidence that melatonin or ramelteon improves sleep for people with dementia due to Alzheimer's disease. There is limited evidence that a low dose of trazodone may improve sleep, however more research is needed.

There is no solid evidence that folate or vitamin B12 improves outcomes in those with cognitive problems. Statins also have no benefit in dementia. Medications for other health conditions may need to be managed differently for a person who also has a diagnosis of dementia. The MATCH-D criteria can help identify ways that a diagnosis of dementia changes medication management for other health conditions. It is unclear if there is a link between blood pressure medication and dementia. There is a possibility that people may experience an increase in cardiovascular-related events if these medications are withdrawn.

In late 1983, Italian neurologist/sleep expert Dr. Ignazio Roiter received a patient at the University of Bologna hospital's sleep institute. The man, known only as Silvano, decided in a rare moment of consciousness to be recorded for future studies and to donate his brain for research in hopes of finding a cure for future victims. As of 2017, no cure or treatment has yet been found for FFI. Gene therapy has been thus far unsuccessful. While it is not currently possible to reverse the underlying illness, there is some evidence that treatments that focus solely upon the symptoms may improve quality of life.

It has been proven that sleeping pills and barbiturates are unhelpful; on the contrary, in 74% of cases, they have been shown to worsen the clinical manifestations and hasten the course of the disease.

One of the most notable cases is that of Michael (Michel A.) Corke, a music teacher from New Lenox, Illinois (born in Watseka, Illinois). He began to have trouble sleeping before his 40th birthday in 1991; following these first signs of insomnia, his health and state of mind quickly deteriorated as his condition worsened. Eventually, sleep became completely unattainable, and he was soon admitted to University of Chicago Hospital with a misdiagnosis of clinical depression due to multiple sclerosis. Medical professionals Dr. Raymond Roos and Dr. Anthony Reder, at first unsure of the nature of his illness, initially diagnosed multiple sclerosis; in a bid to provide temporary relief in the later stages of the disease, physicians attempted to induce a coma with the use of sedatives, to no avail as his brain still failed to shut down completely. Corke died in 1993, a month after his 42nd birthday, by which time he had been completely sleep-deprived for six months.

One person was able to exceed the average survival time by nearly one year with various strategies, including vitamin therapy and meditation, using different stimulants and hypnotics, and even complete sensory deprivation in an attempt to induce sleep at night and increase alertness during the day. He managed to write a book and drive hundreds of miles in this time but nonetheless, over the course of his trials, the person succumbed to the classic four-stage progression of the illness.

In the late 2000s, a mouse model was made for FFI. These mice expressed a humanized version of the PrP protein that also contains the D178N FFI mutation. These mice appear to have progressively fewer and shorter periods of uninterrupted sleep, damage in the thalamus, and early deaths, similar to humans with FFI.

As of 2016, studies are investigating whether doxycycline may be able to slow or even prevent the development of the disease.

Kuru is largely localized to the Fore people and people with whom they intermarried, and was transmitted through ritualistic cannibalism. The Fore people ritualistically cooked and consumed body parts of their family members following their death to symbolize respect and mourning. Because the brain is the organ enriched in the infectious agent prion, women and children, who consumed brain and viscera, had much higher likelihood of being infected than men, who preferentially consumed muscles.

Aromatherapy and massage have unclear evidence. There have been studies on the efficacy and safety of cannabinoids in relieving behavioral and psychological symptoms of dementia.

Omega-3 fatty acid supplements from plants or fish sources do not appear to benefit or harm people with mild to moderate Alzheimer's disease. It is unclear if taking omega-3 fatty acid supplements can improve other types of dementia.

In October 2007 an astute medical interpreter noticed similar neurological symptoms being reported by Spanish-speaking patients seeking treatment from different physicians at the Austin Medical Center, in Austin, Minnesota. Not only did these patients share similar neurological symptoms, they also worked at the same pork processing plant. Dr. Daniel LaChance, a physician at both the Austin Medical Center and the Mayo Clinic in nearby Rochester, Minnesota, was notified. He launched a request to area physicians to refer other patients with similar symptoms to him. The Minnesota Department of Health (MDH) was notified and began an investigation into the "outbreak." The MDH identified workers from two other pork processing plants in Indiana and Nebraska who also had parallel neurological complaints. Several agencies including the Occupational Safety and Health Administration (OSHA) and the Center for Disease Control and Prevention (CDC) were brought in to assist. Simultaneously investigations were conducted to rule out contagious disease, to locate the source or carrier, and to identify what exactly was causing these workers to develop these symptoms.

Removal from exposure was the first line of treatment. Due to progressive sensory loss and weakness, immunotherapy was often required. These treatments included intravenous methylprednisolone, oral prednisone, azathioprine, and/or immunoglobulin. All 24 patients improved, including 7 who received no treatment and 17 who required immunotherapy.

Specific and accepted scientific treatment for PCA has yet to be discovered; this may be due to the rarity and variations of the disease. At times PCA patients are treated with prescriptions originally created for treatment of AD such as, cholinesterase inhibitors, Donepezil, Rivastigmine and Galantamine, and Memantine. Antidepressant drugs have also provided some positive effects.

Patients may find success with non-prescription treatments such as psychological treatments. PCA patients may find assistance in meeting with an occupational therapist or sensory team for aid in adapting to the PCA symptoms, especially for visual changes. People with PCA and their caregivers are likely to have different needs to more typical cases of Alzheimer's disease, and may benefit from specialized support groups such as the PCA Support Group based at University College London, or other groups for young people with dementia. No study to date has been definitive to provide accepted conclusive analysis on treatment options.

Available treatment falls into two modalities: treating infections and boosting the immune system.

Prevention of Pneumocystis pneumonia using trimethoprim/sulfamethoxazole is useful in those who are immunocompromised. In the early 1950s Immunoglobulin(Ig) was used by doctors to treat patients with primary immunodeficiency through intramuscular injection. Ig replacement therapy are infusions that can be either subcutaneous or intravenously administrated, resulting in higher Ig levels for about three to four weeks, although this varies with each patient.

In terms of treatment for neuromuscular diseases (NMD), "exercise" might be a way of managing them, as NMD individuals would gain muscle strength. In a study aimed at results of exercise, in muscular dystrophy and Charcot-Marie-Tooth disease, the later benefited while the former did not show benefit; therefore, it depends on the disease Other management routes for NMD should be based on medicinal and surgical procedures, again depending on the underlying cause.

There is usually an indication for a specific identification of an infectious agent only when such identification can aid in the treatment or prevention of the disease, or to advance knowledge of the course of an illness prior to the development of effective therapeutic or preventative measures. For example, in the early 1980s, prior to the appearance of AZT for the treatment of AIDS, the course of the disease was closely followed by monitoring the composition of patient blood samples, even though the outcome would not offer the patient any further treatment options. In part, these studies on the appearance of HIV in specific communities permitted the advancement of hypotheses as to the route of transmission of the virus. By understanding how the disease was transmitted, resources could be targeted to the communities at greatest risk in campaigns aimed at reducing the number of new infections. The specific serological diagnostic identification, and later genotypic or molecular identification, of HIV also enabled the development of hypotheses as to the temporal and geographical origins of the virus, as well as a myriad of other hypothesis. The development of molecular diagnostic tools have enabled physicians and researchers to monitor the efficacy of treatment with anti-retroviral drugs. Molecular diagnostics are now commonly used to identify HIV in healthy people long before the onset of illness and have been used to demonstrate the existence of people who are genetically resistant to HIV infection. Thus, while there still is no cure for AIDS, there is great therapeutic and predictive benefit to identifying the virus and monitoring the virus levels within the blood of infected individuals, both for the patient and for the community at large.

Treatment varies according to the type and severity of the encephalopathy. Anticonvulsants may be prescribed to reduce or halt any seizures. Changes to diet and nutritional supplements may help some patients. In severe cases, dialysis or organ replacement surgery may be needed.

Sympathomimetic drugs can increase motivation, cognition, motor performance and alertness in patients with encephalopathy caused by brain injury, chronic infections, strokes, brain tumors.