The EEB seems to be caused by the presence of abnormal priones proceeding from the sheep with an illness similar that affects these called "scrapie". The cows acquire these priones across piensos enriched with flours of meat and bones of sheep, which production process had been modified at the beginning of the 80s.

A certainty is not had if there exists the possibility of transmission of these priones between animals of the same species (cow - cow), for it if the forms of feeding of the cows the epidemic is modified it can disappear, and at this there point the tendencies of the principal epidemic that have happened in Great Britain.

The priones are proteins of the surface of nervous cells that possess the aptitude to infect to other cells, that is to say, that have aptitude to reproduce as the bacteria and viruses that produce the habitual infectious illnesses.

In the normal cells there exist these normal priones that call protopriones, but on having changed his structure into mutation of the genes ó for the priones influence (scrapie) of another origin, they transform in priones with aptitude to produce different cerebral illnesses.

The priones are very resistant to different means, and for it they can penetrate digestive route in spite of the acidity and adverse conditions of the digestive tract of the mammals.

It is a cerebral degenerative illness that affects the man.

The Illness of Creutzfeldt-Jakob (ECJ) is a rare degenerative disorder of the brain that has a progressive evolution towards the death within one year. It affects 1 person for every million inhabitants, principally in individuals older than 60 years.

The first symptoms of the Illness of Creutzfeldt-Jakob include typically:

• Dementia,
• Changes of personality,
• Deterioration of the memory, the indictment and the thought,
• Problems of muscular coordination,
• Insomnia, depression or unusual sensations,
• Involuntary muscular contractions called mioclono,
• He can remain a blind person or lose control of the bladder,
• With the time the patients lose the aptitude to move, to speak and enter comma.
• The pneumonia and other infections happen often in the patients of this illness and can drive to the death.

To confirm the illness an analysis of a protein exists, 14-3-3 in the spinal liquid. This test helps to diagnose the ECJ in persons who already present clinical symptoms of the illness, although largely of the cases the diagnosis is confirmed on having studied the cerebral textile of the affected ones, often after dying.

Several forms of the illness exist:

• In the sporadic ECJ, 85 per cent of the cases.
• In the hereditary ECJ, of 5 to 10 per cent of the cases of ECJ.
• In the acquired ECJ, the illness is transmitted by exhibition to the cerebral textile or of the nervous system, less than 1 per cent of the cases has belonged to acquired ECJ.
• The juvenile variant described in Great Britain is different clinically, and seems related to the epidemic of the cows. In the form transmitted (possibly) more precozmente appears with psychiatric and sensory alterations, in addition to appearing in young persons of less than 30 years.

From the death of the first case of ECJ of the new variant ó juvenile (nvECJ) in 1995, have detected to themselves more than 90 "confirmed" and "probable" cases of nvECJ in Great Britain. The incidence increases to an estimated rhythm of 20 % 30 % per year. In other European countries it has described isolated cases.

With the epidemic EEB in the United Kingdom, many persons worried before the possibility about contracting nvCJD across the consumption of contaminated meat. At present there are no even evidences of which the man is capable to the infectious EEB agent, but yes there are demonstrated cases of other animals (like pigs and cats) that they have developed encefalopatías espongiformes after having consumed infected meat.

Theories in favor of the relation of both epidemics (cows - men):

• The appearance of juvenile forms nvCJD, the increase of them, and the being in Great Britain.
• Having the biggest EEB epidemic in the cows in Great Britain. More than 130.000 cows have died of BSE in the United Kingdom.
• The experimental argument that unleashed the polemic, was the discovery of similar injuries in a macaque infected by EEB and the patients dead of nvCJD.

Theories in against:

• The differences of priones between the species it is very big, the chains of amino acids between the priones of sheep and of the cows it is alone of 7 positions and on the other hand between the priones of the cows and those of the man in more than 30 of 254 positions.

In any case in the year 1996, 1997 and 1998 the World Organization of the Health (WHO) organized experts' consultations on BSE and the nvCJD. These experts confirmed that the most commendable hypothesis relative to the nvCJD was the exhibition of the population of the United Kingdom to the EEB.

It seems that the accumulation of these priones is in nervous textiles, gores, and/or guts, but it is not known in its entirety for the time being.

The EEB epidemic in the cows affects Great Britain (principally), Ireland, Portugal, France, and other sporadic cases in other European countries like Spain.

The piensos proceeding from animals for the feeding of the cows have been prohibited in Europe.

The control of the cows by means of an analysis of detection of the EEB, is going to be realized in all the suspicious animals, and in the persons older than 4 years.

The human consumption of food proceeding from the cows in general is of young animals, for it without development of the illness.

All these measurements must be sufficient so that the risk, and especially the fear of being contagious of this illness for eating meat disappears in Europe.

Yes it is true that between the contagion and the appearance of the illness in the man can happen 10 years, and it is for it that the epidemic in the man can still keep on generating fear of eating meat in the society. But the preventive means are taken, and the present and future seems to be under control.

It is not necessary to eat meat products of the cows, especially guts, nervous textiles, ganglions, intestines, etc... of cattle and slaughterhouses not controlled sanitarily.

The measurements taken the sanitary authorities must be sufficient so that the encefalopatía espongiforme epidemic disappears in a few years, and possibly the prevention depends more of the sanitary organisms and experts' committees, with the general preventive measurements, which of the nutritive customs of the population.