What is Creutzfeldt-Jakob Disease?

Mad cow disease is likely to be transmitted to humans. In humans, we call it variant or new variant Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease is a rare, transmissible encephalopathy that occurs primarily between the ages of 50 and 70. Infected people can have symptoms such as sleep disturbances, personality changes, ataxia, aphasia, vision loss, physical, muscular atrophy, myoclonus, progressive dementia, and can die within one year of onset. The disease is often genetically predisposed to chromosomal families and a new report of Creutzfeldt-Jakob disease has been linked to bovine spongiform encephalopathy. The pathological features of the disease include spongiform degeneration dominated by the cerebellum and cerebral cortex and the appearance of prions.

Creutzfeldt-Jakob disease overview

Mad cow disease is likely to be transmitted to humans. In humans, we call it variant or new variant Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease

Mad cow disease, scientific name bovine spongiform encephalopathy, is an infectious disease that harms the central nervous system of cattle.

The diseased cow's brain showed spongy lesions, symptoms such as gait instability, imbalance, itching, irritability, etc., and died within 14 to 90 days. Depending on the species, the incubation period of BSE varies, usually between 2 and 30 years.

Mad cow disease was first thought to be a new nervous system disease in cattle and was discovered between 1984 and 1985. At that time, cattle on the British farm were found to have contracted this neurological disease and were contagious. Veterinary experts at the laboratory of the British Veterinary Centre of the British Veterinary Centre, when dissecting the brain of a sick cow, found that the brain tissue of the sick cow was sponge-like degeneration. According to pathological changes, in November 1986, this nervous system disease was named bovine spongiform encephalopathy.

The etiology, pathogenesis, and epidemic modes of mad cow disease have not been uniformly recognized in the medical community, and effective diagnostic methods and prevention measures have not been found. However, experts generally believe that mad cow disease originates from sheep scrapie and is caused by feeding ruminant protein feed containing sheep scrape factor to cattle. Before 1988, the UK used feeds made from ruminants, such as viscera and scraps of sheep and cattle, to feed cattle. Sheep scrapes were transmitted to cattle through these feeds. The carcasses of diseased cows enter the food chain of the cows after processing, causing cross-infection between the cows.

Experts believe that BSE is related to a spreadable vector. This medium is very stable and has a strong resistance to heat, ultraviolet rays, radiation and a variety of chemical disinfectants. It cannot be killed by ordinary cooking temperatures and disinfection, freezing and drying.

People who eat beef and bovine spinal cord contaminated with mad cow disease may develop fatal Creutzfeldt-Jakob disease. The patient first appeared restless, and eventually died of insanity.

At present, international understanding of Creutzfeldt-Jakob disease and variant Creutzfeldt-Jakob disease is that infectious prions, that is, a mutant of the normal protein PrP on the surface of nerve cells, are also known as purine or protein After entering the human brain, it can remain stationary for 15 years, but once the prion is stimulated, the disease will occur and cause death in as little as 12 to 18 months. Symptoms include depression, coordination problems, memory loss, emotional instability, acupuncture sensations in the extremities, severe headaches, severe colds, foot pain, reddened skin, and transient memory loss. Most of the less than 200 cases of variant Creutzfeldt-Jakob disease currently found worldwide are young people (the average age of death is 28 years). A variety of mammals have diseases caused by Puri, which is "mad cow disease" in cattle, sheep scrapie in sheep, and chronic atrophy in deer. The effects of these diseases on the structure of brain tissue are fatal and incurable.

Creutzfeldt-Jakob disease prognosis

The prognosis is extremely poor, and all known cases have died.

Creutzfeldt-Jakob disease pathogenesis

So far, the pathogenesis of Creutzfeldt-Jakob disease has not been conclusive, and no effective treatment has been found. However, experts generally believe that Creutzfeldt-Jakob disease or variant Creutzfeldt-Jakob disease is transmitted mainly through family genetics and exposure to prion-contaminated devices during surgery (prions can survive in autoclaves that usually disinfect surgical instruments ), Injection of growth hormone directly derived from the human pituitary gland and infection, and consumption of contaminated beef or bovine spinal cord. The medical community is currently unable to confirm the diagnosis of variant Creutzfeldt-Jakob disease while the patient is alive. The main method is to perform a biopsy after the patient's death and analyze whether the patient's brain has prions.

It should be noted that prions are not real viruses, because they are essentially a protein and do not contain the nucleic acid substances that the viruses possess. Therefore, some people think that prions are not a good translation, and the current common translation is Prion or Prion protein.

Creutzfeldt-Jakob disease diagnosis principles and criteria

1.General principles of diagnosis and treatment

(1) Diagnosis based on clinical symptoms and signs such as progressive dementia, myoclonus, abnormal pyramidal / extrapyramidal dysfunction, visual disturbance, electroencephalogram, cerebrospinal fluid, neuropathology, and etiology

(2) The central nervous system tissue and eyeball tissue of CJD patients are highly infectious, and other tissues such as tonsils, spleen, and lymph nodes are also infectious. Care should be taken when touching these tissues.

(3) There is no information showing that CJD can be transmitted through contact.

2. Diagnostic criteria

(1) CJD

confirmed diagnosis

With typical / standard neuropathological changes, and / or immunocytochemical and / or Western blotting identified as protease-tolerant PrP, and / or the presence of pruritus-associated fibers.

Clinical diagnosis

With progressive dementia, typical EEG changes during the course of the disease, and / or 14-3-3 protein positive for cerebrospinal fluid, and at least two of the following four clinical manifestations,

a. Myoclonus

b. Visual or cerebellar disorders

c. Cone / extrapyramidal dysfunction

d. Apathetic silence

And the clinical course is shorter than 2 years.

Suspected diagnosis

Have progressive dementia, and have at least two of the following 4 clinical manifestations,

a. Myoclonus

b. Visual or cerebellar disorders

c. Cone / extrapyramidal dysfunction

d. Apathetic silence

And the clinical course is shorter than 2 years.

All diagnoses should exclude other dementia-related diseases.

(2) Iatrogenic CJD

Based on the diagnosis of sporadic CJD,

Patients undergoing treatment with pituitary hormones extracted from the human brain develop progressive cerebellar syndrome; or

Identified exposure risks, such as having undergone dura mater or corneal transplant.

(3) Family hereditary type CJD

Familial hereditary CJD includes familial CJD, Gerstmann-Straussler-Scheinker syndrome (GSS), and fatal familial isomnia (FFI).

CJD patients with confirmed diagnosis or clinical diagnosis have specific PrP mutations in this disease, and / or CJD cases with confirmed diagnosis or clinical diagnosis in first-degree relatives

(4) Variant CJD (variant CJD, vCJD)

Medical history

a. Progressive neuropsychiatric disorder

b. Course of disease 6 months

c. Routine examination does not suggest other diseases

d. No history of iatrogenic contact

Clinical manifestations

a. Early psychiatric symptoms (depression, anxiety, apathy, withdrawal, delusion)

b. Persistent pain (pain and / or paresthesia)

c. Ataxia

d. Myoclonus, chorea, dystonia

e. dementia

Clinical test

a. EEG without typical CJD wave pattern (three-phase periodic composite wave appearing about once per second), or without EEG detection

b. High signal of bilateral posterior thalamus nodules in MRI proton density phase

Positive tonsil biopsy

(Tonsill biopsy should not be used as a routine test, and should not be performed after a typical sporadic CJD-like wave pattern on the EEG. The clinical manifestations are similar to vCJD, and MRI does not show a high signal of bilateral posterior thalamic nodules significance.)

Diagnosis

a. Confirmed diagnosis: a and vCJD neuropathological diagnosis (extensive vacuole-like changes in the brain and cerebellum and "petal-like" PrP plaque deposition)

b. Clinical diagnosis: Have any 4 of and , and or and

c. Suspected diagnosis: with any 4 of and , and a

Creutzfeldt-Jakob disease prevention principles

At present, because conventional disinfection methods are not effective against pathogenic factors (prion bodies), serology cannot be detected after infection, and tissues are already infectious during the incubation period. Therefore, Prevention and control have received great attention from the international community. Recently, the Food and Agriculture Organization and the WHO issued a statement stating that it is necessary to stop using animal-derived protein, especially imported from Western Europe such as the United Kingdom, to feed animals. Since 2001, European countries and organizations have taken proactive measures to monitor mad cow disease. The Chinese Ministry of Agriculture and other relevant departments have repeatedly stated the relevant bans and monitoring measures for the prevention of mad cow disease. The United Kingdom is a country with frequent vCJD. It strictly implements unified management of the blood and blood products of all patients who die from the disease. Because white blood cells are the carrier of the disease, some countries import white blood and blood products from the United Kingdom to remove white blood cells. To prevent. The United States strictly prohibits blood donation to anyone who has been to the UK or has lived in the UK for more than 6 months during the 1980s and 1990s. There is no vaccine for effective immunoprevention or effective drug treatment for prion disease. At present, measures are taken to prevent the possible transmission of the disease.

(1) Prevention of iatrogenic CJD:

On the one hand, it is necessary to prevent transmission through blood donation or organ donation, and on the other hand, to prevent iatrogenic infection caused by incomplete disinfection and sterilization of contaminated surgical instruments and utensils during surgical operations, especially neurosurgery and ophthalmology. The patient's blood and other body fluids and surgical instruments must be thoroughly sterilized, and the animal carcasses, tissue blocks or syringes containing the cause of the disease must be completely destroyed. Surgical instruments must be treated with 1 mol / L NaOH for 1 h, and then cleaned and then autoclaved (134 ) for 1 h; for extracts and blood with PrPsc, 10% bleach solution or 5% sodium hypochlorite should be treated for 2 h The above makes it infectious. It is strictly forbidden to donate tissues and organs from iatrogenic CJD patients; medical staff and laboratory researchers should strictly abide by safe operating procedures, strengthen precautionary awareness, and pay attention to self-protection.

(2) Prevention of BSE and vCJD:

It is forbidden to use the visceral bone and meat meal of ruminants such as cattle and sheep as feed additives to feed ruminants such as cattle to prevent pathogenic factors from entering the food chain. For live cattle (including embryos) and their products imported from countries where BSE occurs, special quarantine and comprehensive follow-up investigations must be strictly conducted to strengthen surveillance to prevent imported infections.