Physicians warn of Creutzfeldt-Jakob epidemic

Mad Cow Disease: Deadly Creutzfeldt-Jakob Disease

08/12/2014

Only a few years ago it was said that the so-called „mad cow disease“ (BSE) was almost defeated in Europe. Creutzfeldt-Jakob disease (CJD), most likely caused by the consumption of BSE-contaminated beef, appears to remain dangerous. The causative agent of the fatal disease is still prevalent.

Creutzfeldt-Jakob disease is always deadly
Earlier in the decade it was reported that experts assume that the so-called „mad cow disease“ (BSE, bovine spongiform encephalopathy) is almost defeated in Europe. But the human form of mad cow disease, the Creutzfeldt-Jakob disease, remains obviously dangerous. The so-called new variant of the disease (vCJD) is distinguished from the coincidental (sporadic) Creutzfeldt-Jakob disease. In the vCJD, depression, anxiety, delusions and hallucinations usually start to develop. Later on there will be severe movement disorders and loss of mental capacity (dementia). Both the sporadic and the new variant of the brain disease is always deadly. In a recent article is dedicated to „world“ the topic.

BSE can be transmitted to humans
About two decades ago, BSE, the disease that culled the brain, is transmissible to humans. The first young women and men developed symptoms of the new epidemic. First scientific contributions to the so-called vCJK followed in 1995. „For professionals, it was not surprising that BSE can be transmitted“, explained Professor Inga Zerr from the University of „world“ according to. „However, no one thought that those affected would be much younger than CJK patients before.“ The two patients, about the British neurologists at that time in the specialist magazine „Lancet“ were 16 and 18 years old. The most recent patient was reported to be twelve years old at onset. People with vCJD die on average before their 30th birthday. „The fluctuation range is however large“, so Zerr.

Hope for expiry of the disease wave
Worldwide, a total of 229 cases of the new variant were registered at the CJK Monitoring Center in Edinburgh until June 2014, of which 177 were from the United Kingdom. „In Germany so far not a single case has become known“, Zerr explained. Since the peak in 2000, the numbers have fallen and there was hope for the expiry of the disease wave. However, Professor Armin Giese of the Ludwig-Maximilians-Universität München warns: „The silence can be deceptive.“ According to the report, half of the population could still face a wave of vCJD diseases. „This is a very realistic scenario“, also finds Zerr. The risk is purely theoretical. There are no direct references so far. „It may also be that nothing happens“, so the neurologist. „And this possibility is becoming more likely from year to year.“

Incorrectly folded protein molecule responsible for disease
Creutzfeldt-Jakob is caused by a misfolded small protein molecule called a prion. If malformed prions reach the brain, for example after consuming BSE-contaminated beef, the consequences can be fatal. As the „world“ writes, fold in a kind of domino effect, the body's own proteins in the wrong folding, which in turn degenerate the brain tissue and sponge-like perforated structures arise. For the own disease risk the place 129 of the prions composed of amino acids is decisive. So far, only humans with two genes for the amino acid methionine at this point fell ill. Such a double methionine gene has 40 percent of the population. About the vCJK risk of ten percent, who have written a double instructions for the amino acid valine in the genome, nothing is known. For the remaining 50 percent, which each have a plant for methionine and one for valine, but there are grim indications.

Hormones from the pituitary gland of corpses
For example, in the case of the prion disease Kuru, people with two identical genes first fell ill and later also those with mixed genetic material. Since it was customary among the people in Papua New Guinea to eat meat from deceased tribesmen, misfolded prions continued to spread and more and more people died until cannibalism was banned in 1954. In the CJD diseases of people who received growth hormones from the pituitary gland of corpses in the 1960s and 1990s, a similar difference was shown. In both cases, the incubation period was twice as long for the mixed patients as for the carriers of two identical genes. In most cases, vCJK assumes that the methionine / methionine population is about 10 to 15 years old. „But that's just an estimate, starting from the BSE maximum“, so Zerr, „You never know when the individual got infected.“ For half of the population, the incubation period could thus be between 20 and 30 years. „But that is pure statistical gimmick.“

Security only in 20 years
However, many people carry misfolded prions without being ill with vCJD. „After initial cases, the United Kingdom has deliberately tested how high the population is?“, so Giese. Examination of thousands of tissue samples of almonds and caudal bowels removed from surgery revealed that „on average one out of 2,000 people carriers of misfolded prions“ is. However, as the prion researcher explained, the result does not mean that the disease will still erupt in all these people. „It may be that the amount in the body remains low and they never get sick.“ Although it is clear that there is a risk with the many carriers to transmit diseased prions via surgical instruments or blood donations, so far in the database in Edinburgh, only three vCJK deaths derived from blood donors are recorded. „At worst, the disease can become endemic“, so Zerr. In the best case, nothing happens. „Only in 20 years you will be able to say for sure: Everything went well.“

No therapy and no approved blood test
Independently of the sporadic Creutzfeldt-Jakob disease, 100 to 130 people will continue to suffer from it each year. The majority of patients are 60 to 70 years old. „Only three to six sufferers annually are younger than 50“, explained Zerr. There is no cure for the disease and no approved blood test for diagnosis. „For the big pharmaceutical companies this is not interesting because of the small number of cases“, so Zerr. Patients initially experience symptoms such as headaches, memory disorders, hallucinations, personality changes, paralysis and dementia. In the further course of the disease leads to more and more errors and finally the complete failure of all brain functions. Affected remain in the final stage, which can last a long time, in a kind of rigidity without possibility to still contact with the environment. „What remains is a breathing and metabolic shell with a pumping heart“, so Giese.

Disease slowed down in animal experiments
The sporadic CJD leads on average within six months to death, the other variant in more than twice as long a period. Even if there are no clear differences in the symptoms, a safe distinction is still possible. „VCJK has vesicular changes with typical deposits in the brain“, Zerr explained. But this can only be checked after death. „During his lifetime, certain changes in the thalamus can be seen as a bright signal in the nuclear spin.“ Although a blood test on CJK already works as a test procedure, there are still too many positive results, that is, an attack without a pathogen. Even after a therapy continues to be researched. Here is the active ingredient „anle138b“, which intervenes in the process of refolding, according to Giese, a bearer of hope. At least in animal experiments, the disease was slowed down. Clinical trials with first patients are due to begin next year. All previous therapeutic approaches have in common that they only benefit from a very early intervention. „Nerve cells that are lost are lost“, said Giese. Zerr added that an interesting and important one „In addition to knowledge“ CJK research suggests that similar processes in the brain may also play a role in Parkinson's and Alzheimer's disease. „We would not have recognized that without intensive prion research.“ (Ad)