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BSE

Bovine Spongiform Encephalopathy (B S E) was first described in 1986 related to cattle feed containing meet and bones from carcasses of sheep being feed to bovines.
On the 70th the preparation of animal feed was simplified, and the temperature reduced. The agent of BSE could now survive and Great Britain became the hotbed of the mad cow disease. The zoologist Sir Richard Southwood [1] blames us all because we all want to eat cheap food.
Science, agriculture and politics have failed to get the disease under control. In the meanwhile 27 persons died on CJD "new variant Creutzfeldt-Jacob-Disease".
It seems to be the start of a horrible epidemic.


Human diseases caused by priones have different forms

Kuru

The tribe of fore in Papua-Newguinea were cannibals, eating brains of diseased.After ceasing the cannibalic practice new infections were no more recorded.
The disease was called Kuru and was characterized by loss of coordination of movements developing until madness.

Creutzfeldt-Jakob disease

Is spread through out the world, being described in 1920 by Creutzfeldt and Jacob.
The disease begins at the age of 60 with disturbed sleep, hallucination, dementia, unable to speak and to read, and alterations of movements. It leads to death within several month up to two years
10 to 15% of all cases of CJD are of hereditary origin.A small number is transmitted by surgical interventions, such as transplants.

Gerstmann-Sträussler-Scheinker Syndrome and Lethal Familiar Insomnia [2]

The signs of the disease are similar to those of the CJ disease.All these diseases are caused by proteins priones (PrP) (Proteinaceus infectious Particles)[3]. These proteins remain infectious even after being treated by methods of lesion of nucleic acid, however lose their virulence when treated with hydrolysing or denaturing substances.

Genetic cause Priones or PrP - Proteins exist in two forms:
One form causes the CJD (Creutzfeldt-Jakob Disease) disease being infectious.
The other form of PrP- Proteins is not pathogenic and is synthesized by the organism himself. It is not contagious.

The theory that priones also can cause CJD through a genetic mechanism was explained by Prusiner. In 1988 it was discovered that patients with Gerstmann-Sträussler-Scheinker syndrome had a change in their genetic code, compared with healthy persons.

The contagious PrP-protein may be inherited. The difference between the genetic code from these patients compared with healthy persons lies in a change at the Gen-PrP from the DNA, one of the 750 radicals from the part of the DNA responsible for the synthesis of PrP protein. These radicals are the alphabet from which the genetic code is composed.

Her sequence in the molecule of DNA decides the composition of the proteins. The code for the synthesis of each aminoacid is represented by three basic radicals. This part is called CONDOM. In the case of the syndrome of GSS the condom 102 suffers a mutation. The PrP protein has a proline aminoacid in the place where normally the basic radical leucine is located.

This small change in the structure of the PrP is responsible for the start of the disease of GSS. Today 18 types of genetic modifications which are responsible for the synthesis of PrP-scrapie are known. The normal form of PrP protein found in healthy people is called PrP-cellular.

PrP-scrapie has turned out to be the global denomination for all diseases close related to the human and animal scrapie. The specific activity of PrP scrapie consists in its stereoisomeric configuration. The PrP scrapie does not necessarily present a genetic mutation related to a change of leucine by proline. What matters is that molecules of PrP having the same distribution of aminoacids differ in their stereoisomeric configuration. The priones are able to transfer her stereoisomeric configuration to other normal molecules of PrP-cellular which now turn out to be infectious.

The structure with this property is called twisted beta structure. The aminoacids have a beta-helicoidal twisted screw form and represent the scrapie PrP. The cellular PrP form has a twisted alfa-helicoidal chain. In some places of the alfa-helicoidal chain there may be a change of aminoacids which cause an unstable condition in the molecule being therefore vulnerable to an inversion of her twist, acquiring the same configuration of the scrapie PrP molecule thus becoming infectious.

The pathological activity of scrapie PrP is still partially unknown. It seems that PrP destroys the nervous cells producing amylaceous substances which accumulate as amylaceous plaques which can be seen under microscope.
These plaques are also found in the Alsheimer Disease, Parkinson and amiotrofic lateral sclerosis, demonstrating certain link between these groups of anomalies.

Diseases caused by priones

Priones are particles of infectious proteins causing degenerative diseases of the central nervous system in human and in animals. Unlike other substances which are situated between priones and other superior elements the prions do not have the form of nucleic acid which could be made responsible for reproduction as below: Prions always cause mortal diseases.They are localized in brain and stay without symptoms for decades. They have their influence spread over the muscular system.

Usual spongiform encephalopathies

Scrapie in lamb and goats

The animals can no more coordinate the movements and cannot maintain itself on foot, being frightened and scrape itself until there is no skin left. This gave origin to the name of the disease = to SCRAPE.

Other encephalopathies

Encephalopathies of Canadian marten, chronic degenerative disease of elk, feline spongiform encephalopathy of cat and the bovine spongiform encephalopathy (B S E).

Short story of the measure to control and eradicate BSE in cattle

Despite the growing menace of spreading BSE in cattle mainly in France, Portugal and Switzerland the EU Commission is not willing to forbid animal meal made of bones,carcasses, brains, spinal cord, blood, gelatine, lard and marrow as animal feed for pigs, poultry and fish. Ruminants are not allowed any more to be fed with animal meal.

Animal feed free of animal meal is now being produced in Germany with main ingredients:
Soy bean from USA, Argentina and Brazil.
Rapeseed cake from Pakistan, India and Germany.

Peas, broad been (Vicia faba), sunflower seed cake, maize germ cake and maize gluten feed.
400.000 tons of animal meal can thus be replaced by vegetable ingredients supplying the aminoacids which are necessary for a healthy growth.
Genetic modified Soybean, rapeseed and maize gluten feed must be replaced by NON-GMO to avoid another loss of confidence of the consumer

Live-animal test to detect scrapie in goats [4]

Scrapie is a form of transmissible spongiform encephalopathy in goat and sheep. The degenerative disease causes tremors, lip-smacking, weight loss, a hopping gait, and other peculiar symptoms. Scrapie-afflicted animals cannot be cured, and they eventually die.

Rectal mucosal-associated lymphoid tissue (RMALT)

Katherine O'Rourke and Tom Truscott developed the rectal mucosa biopsy test(RMBT) or rectal biopsy, which consists of snipping a tiny piece of lymphoid tissue from the animal's rectum using local anesthesia. Lymphoid tissue is used because it collects malformed proteins called prions, which are thought to cause scrapie. The RMALT test is based on the currently used third-eyelid test. The rectal biopsy has also been used in deer, elk, sheep, and now goats.

The third-eyelid test

The third-eyelid test has been used by APHIS and state veterinarians since 2002 as an official test to detect scrapie in sheep. It involves snipping a tiny piece of lymphoid tissue from the animal's nictitating membrane, or third eyelid, staining it with antibodies, and examining it under a microscope.

The ARS characterizes the prion protein gene of goats to identify differences between individual animals and those who are diseased. Their work, together with APHIS aims to eliminate scrapie from US herds to reduce costs of physical loss of animals, disposal of carcasses and offal, trade restrictions and diminished domestic and international markets for breeding stock, semen and embryos.

Early Detection method for Prion Diseases

Infectious prions can be present decades before symptons appear, an early detection method is needed for early treatment to stop the spread of the Creutzfeldt-Jakob disease in humans. Prion diseases are difficult to diagnose, untreatable and ultimately fatal. Brain tissue dies out and sponge-like holes are formed in the brain.

Real time quaking induced conversion assay, or RT-QuIC prion detection method [5]

Infectious prions are also found outside the brain, in saliva, blood, breast milk, urine and the nasal and cerebral spinal fluids, however, their concentrations in these bodily fluids are to low to be measured with available methods.

A new prion detection method, called real time quaking induced conversion assay, or RT-QuIC was has been developed by by Byron Caughey. Using this technique the small amounts of infectious prions are leaded to convert large amounts of normal prion protein into an abnormal form which enables their detection. The test detected high levels of prions in nasal fluids of hamsters, pointing to such fluids as possible sources of contagion in various prion diseases. RT-QuIC related applications might also be used to diagnose similar neurodegenerative protein diseases, such as Alzheimer's, Huntington's and Parkinson's diseases.

William and colleagues 2010 estimate the relative amount of prions using the RT-QuIC prion detection method. [6]

Quantitative N-terminal amino acid profiling (N-TAAP) for TSE diagnosis [7]

Gielbert and colleagues 2009 report a method to identify differences between bovine spongiform encephalopathy (BSE), the classical scrapie and experimental transmissible spongiform encephalopathy strains.

Diagnosis of TSE is based on the detection of the abnormal protease-resistant prion protein (PrP(Sc)). Proteolysis by proteinase K (PK) generates protease-resistant products (PrP(res)) with partially variable N-termini.The N-terminal aminoacid profiles (N-TAAPs) is , and can be determined with the method developed by Gilbert and colleagues

Fluorescence Spectroscopy of the Retina for Diagnosis to detect mad cow disease [8]

Fluorescence spectra of the eye for diagnosis of transmissible spongiform encephalopathies (TSEs) may become a new diagnostic tool analysing differences in the fluorescence intensity and spectroscopic signatures. It is based on the accumulation of lipofuscin in the retina. The detection of infectious prion diseases in animals could help prevent the disease from spreading in the food supply.

Scrapie prevention in sheep flocks [9]

ARS uses selective breeding of sheep with the version of the prion protein gene (dubbed "R171") that confers resistance. The R171 prion gene version has never been found in goats, but there are several gene variants in goats which might confer resistance to scrapie. These findings are used in flocks where scrapie is found. Only the genetically susceptible sheep are removed. The researchers found four gene variants (R143, S146, H154, and K222) which were relatively rare or absent in animals that developed scrapie in previous outbreaks, suggesting that they might increase resistance to scrapie.

The current eradication effort includes early detection through slaughter surveillance and reporting of clinical suspects, flock management and selective breeding in sheep, scrapie-free flock certification, and producer outreach and education.

ARS will continue to do research on genetic resistance, diagnostic testing, and transmission modes. To improve prevention rather than removing infected animals.


Milk substitute in organic farming

Milk substitute being fed to young animals should contain only milk fat. other animal fat is to be banned. Milk substitute should therefor be made out of half unskimmed milk and half vegetable fat. The cheap variant using animal fat from condemned animals was certainly a vector of BSE disease which had been fed until December 2000.

It had been discovered that the BSE pathogens are very resistant in fat and can be destroyed only with temperatures of mor than 150°. Fat used in powdered milk substitutes had only been heated up to 100°. All German farmers with BSE in their herd had fed powdered milk substitutes of low temperature origin. All efforts should be undertaken to reduce spreading of BSE regardless to costs and industrial interests.

To inactivate the BSE agents Germany uses 133° heat and 3 bar pressure during 20 minutes to decontaminate the meal. This method is not being used in other countries. France is willing to forbid therefore completely the use of animal meal.
The problem arises how to get rid of 300.000 tons of meal/year which have to be burned, causing dioxins. The proteins demand of 55 to 66% in animal meal must be covered with soybean meal ( 44 to 46 % protein). Stock market reacted immediately with rising prices for soybean meal.

BSE was present in cattle in the Northern Ireland, in Great Britain, Switzerland and in France in the Departments 22 (Côte du Nord), 29 (Finistere), 35 (Ile de Vilalne), 50 (Manche). In February 1997 was discovered a case of BSE in Germany. This cow had been imported from England. Her identification mark had been falsified as being original German. In Switzerland there has been reported recently a case of BSE The contamination in this case was told to be interplacental or over the milk. Since January 1977 until march there were 15 cases of BSE in Switzerland. (Welt am Sonntag 3.3.97).

BSE is therefore not under control.
The European Commission has therefore established a decision in order to strengthen the rules related to BSE: Starting with 1.10.00 the parts like head, brains, eyes, tonsils, spinal cord and a part of the intestine of cattle with more than 12 month of age must be separated and incinerated. In case of sheep and goats additionally the melt must be removed and incinerated.

This rule is valid in all countries of the EU, This rule is also valid for the production of animal flour for feedstuff.


Germany in level two of BSE-risk

The European Commission in its report from June 2000 has classified Germany as level two of the risk of BSE. Germany is surpassed only by Great Britain and Portugal in BSE risk.

During the time of uncontrolled spread of infected corpses Germany had imported infected meat and animal feed from great Britain. The EU Commission expects therefore many cases of BSE and CJD in Germany.
In February 2001 the total number of 41 BSE positive cases had been reported in Germany.
Concerns over gelatin (used in Food and medicaments capsules
dragees etc) following the BSE crisis in Europe and thus being spread over the whole world have led researchers to look after alternatives.

Alternatives to gelatin


Lecithin from brains and nervous system material

Lecithin extracted from brains and nervous systems from BSE cattle was used in the production of chocolate.

What is safe and what is a deadly menace?

As BSE still keeps going and meal from diseased animals is still being fed there is no safety for European beef.
All BSE-tests like Prionics are only safe when the animal already has clinical signs of the disease. In Germany 60% of cattle is slaughtered being under two years of age when tests fail.

To be sure not to get the deadly CJ disease try to get beef from Argentina,Australia, Chile, New Zealand and Paraguay. There is canned meat imported from these countries. Corned beef is safe, but it is very salty.
Very dangerous is meat from Great Britain, Portugal, France,Switzerland,Spain, Germany and everything which comes from eastern countries like Poland, because contaminated, unsafe meat is sold there to be imported in the European Community.

In USA there are cases of BSE in wild animals. All care should be made to avoid the spread of BSE in USA cattle. Wild animals should therefore not be used in the production of meal for animal feed because transmission of priones is still unknown. Unsafe are stock cubes and dry soups and sauces as they contain meat extracts .

Prion tests for animals and human use

As The menace of BSE disease and CJD increases the search for a safe test on blood which can demonstrate the presence of the disease in animal and in human beings turned out to be a run against the time.

There are other diseases which are probably caused by priones like parkinson and Alzheimer, rheumatic forms and some sort of tumors which may interfere in the immunological reactions used for the diagnosis. Boehringer Ingelheim ( Germany ) tries to find such a test. Prionics is now in use to test animals on BSE but it is not safe as there are many false negative results.

Rapid post mortem tests to detect TSE (Transmissible Spongiform Encephalopathy) in small ruminants not safe [14]

The situation of Transmissible Spongiform Encephalopathy (TSE) of small ruminants like goats and sheep in Europe is analysed by the EU Food Safety in its release "new information about TSE in goats". [15]

Evaluation of the validated TSE tests found that they do not perform equally toward atypical cases and that difference in performance result in under- or non recognition of various types of scrapie. Moreover, a new type of TSE (atypical scrapie cases/NOR98) not previously recognized in the EU, was detected in small ruminants. Currently atypical/Nor98 has been detected in a large number of European countries and approximately constitutes 80% of test positive cases identified in EU.

New tests have to successfully pass all stages of a new evaluation process.
New tests should detect classical scrapie, atypical scrapie and BSE in sheep and detection of preclinical cases and comply with criteria on limitations posed by analytical sensitivity in comparison with bioassay. The criteria set higher standards than have previously been approved for validation of small ruminant post mortem TSE tests for classical scrapie and BSE as well as for atypical scrapie.

Considering data available about abnormal PrP distribution in the three recognized small ruminants TSE forms (BSE, classical scrapie and atypical scrapie) the use of brainstem appears to be the best compromise for detection of all TSE agents in small ruminants. In consequence, officially confirmed (by CRL and NRL) positive/negative brainstem will be used for the evaluation of tests.

The BIOHAZ panel recommends that tests already approved for the detection of TSE in small ruminants should be required to participate in the new evaluation in order to confirm their robustness and their ability to fulfil the additional performance requirements (e.g. atypical cases and analytical sensitivity).

New method to detect BSE infectious mad cow prions [16]

Christina J Sigurdson and colleagues 2007 developed a method based on a fluorescent molecule, a conjugated polymer for detecting and characterizing prions. The new method can distinguish between different strains of prions, whereas the classic methods like antibodies detection and the Congo red staining do not make the distinction.

As the disease was narrowed down public concern about BSE ebbed away. New methods of diagnosis are, however, being developed, because scientists are aware of a possible species barrier braking of the disease, what could make them rapidly contagious within the species.

The method was tested on BSE, scrapie and mad elk disease (CWD) infected mice. New strains of prions emerged throughout several generations which could be identified with the new method.

According to the authors the luminescent conjugated polymers (LCPs) method, emit conformation-dependent fluorescence spectra, for characterizing prion strains, helping to detect structural differences among discrete protein aggregates and to link protein conformational features with disease phenotypes.

The method is now being adapted to blood controls as several cases are known of human BSE infected donors have transmitted the vCJD disease to other patients during the blood transfusion. [17]

Milk and related products an the risk of transmission of BSE

According to Martin Krönke, professor of microbiology at the University of Cologne milk and related products from diseased cows may contain pathogenic agents of BSE. The transmission of the disease to mankind through milk products is theoretically possible. Krönke is Leibniz-Prize winner 2001 regarding his researches on immunology and cell biology.


Clinical signs of BSE in cows[18]

Cows with BSE disease loss weight, reduce milk. The disease is marked by:
All clinical signs may be intensified by stress such as transport or diminished under calm conditions.
There are no signs that certain breeds or a sex are more susceptible to BSE disease.Incubation period is two to eight years.
Infected animals disease between 2 to 12 years, most frequently 4 to 6 years of age.
On living cattle with signs of BSE normal liquor stands for BSE disease meanwhile central nervous system diseases change liquor with signs of infection. A final diagnosis is the histological alterations of the brain.

In advanced stage of the disease these sings may be absent.
The clinical signs can be used to monitor a herd without complicated tests. These signs should be carefully observed all over the world to avoid an outbreak in other continents. The WHO warns for possible outbreaks of BSE worldwide. According to WHO it may be that the disease is already present in Argentina and Brazil only not being noted because no tests are being made. Brazil is already told to be careless in relation to BSE making no effort to test their cattle. The clinical signs may become useful as they are not expensive and very useful to detect outbreaks of BSE in developing countries. Cows with the clinical signs of BSE should be burned and not be used as human food or animal feed.

Elk Disease in Canada

In western Canada 14.000 domestic elks were slaughtered to control the Elk Disease which is a BSE-like neuropathological disease. 14 elks were found to have clinical signs such as:
Swallow complaints
Loss of orientation
Rapid loss of weight
Death by starving
Canada has about 54.000 domestic elks for meat production which is an important industry in the province of Saskatchewan.
Globalization and the destruction of geographical, economic and ecological isolated units are the main cause of the spread of diseases such as BSE, Elk Disease, Foot and Mouth Disease and other epidemiological relevant epidemics.

BSE-Risk material

BSE-Risk material according to resolutions of the European Commission 2000/418/EG (29.6.2000) and 2001/2/EG (27.9.2001):
Skull, including brain, eyes, tonsils, spinal cord and intestines from cattle, sheep and goats over twelve month of age.
Spleen of sheep and goats of all age
There is a strong possibility that prions reach the blood stream, lung and heart during slaughter by bolt with the slaughter gun as material of the brain squirts all around.

EU rises age of cattle for BSE risk material removal to reduce costs [19]

The European Commission Regulation EC 357/2008 from 22.04.2008 raising the age limit at which the bovine vertebral column must be removed from beef from 24 to 30 months. [20]

The Regulation, based on scientific advice from the European Food Safety Authority (EFSA), increases the age at which the vertebral column of slaughtered cattle must be removed from 24 to 30 months. This measure was possible due to the improvement in the BSE situation and was considered to be safe up to 33 month of age by EFSA in 2007. [21]

The vertebral column is included in the EU list of Specified Risk Material (SRM), considered to pose the greatest risk of BSE transmission, and is required to be removed and destroyed in bovine animals over a certain age, to prevent it entering the food and feed chain.

The European Commission says that the higher age limit for vertebral column removal rises the competitiveness of farmers and meat industries, and reduces the cost of destruction of SMR waste.


BSE infection danger from contaminated pastures

The Ministry of Environment of Germany was concerned with the possibility of cattle infection with BSE prions due to pastures contaminated with manure from diseased animals (early 2000).

According to professor Georg Pauli from the Robert-Koch Institute in Berlin, there is not such a danger. Sheep which lamb outdoor can deposit infectios placenta on the ground. This material is being ingested by other sheep spreading in this way scrapie. Manure contaminated pastures do not present such danger because the prions are unable to multiplicate or stay infectious over more than several weeks on ground but are not assimilated by plants.
Not free of any doubt is the possibility of a direct intake of prions of fresh manure contamination of pastures without the way over a plant host.

BSE infection danger for humans

BSE infection danger for humans are often underestimated. Infectious prions may come from primary infective material from diseased animals.

Secondary infective material is all material coming from slaughterhouse which processes cattle. utensils are contaminated by risk material such as spinal cord cutting the animal corps on halves or the spreading of brain material by the slaughter gun. Cleaning and disinfection in normal industrial processing are not sufficient to avoid BSE risk.

Temperature inactivation of prions takes place only at 330° and a pressure of 3 bar during 30 minutes. Normal cooking, heating and freezing do not inactivate the prions. It is believed small wounds make a direct infection due to contact with BSE material possible. Butchers are therefore advised to take safety precautions.

Risk of disease from animal proteins in feed [22]

According to the EFSA the ruminant epidemic of bovine spongiform encephalopathy was spread in cattle due to feed containing BSE contaminated animal proteins. The practice of feeding animal proteins to cattle and other farmed animals destined for the human food chain had been banned since 2001. The EFSA assessed now the risks certain uses of animal proteins in animal feed.

In their report the EFSA says that no Transmissible Spongiform Encephalopathies (TSEs) have been identified as occurring in pigs or poultry under natural conditions. The EFSA concluded that the risk of transmitting BSE to pigs utilizing poultry Processed Animal Proteins PAPs and vice versa, that means, feeding pigs with poultry proteins and visa versa is negligible. In this case human risk of BSE would be negligible, as long no future TSE infection is found in pigs and poultry.

The risk of transmitting BSE through small quantities of animal proteins in feed to ruminants can not be excluded and would increase the human exposure the risk of BSE.

The risk of transmitting BSE to non-ruminants is considered to be lower than to ruminants, as long as intra-species recycling is avoided, and the increase in the exposure risk of BSE to humans is negligible.

The Commission may now lift the ban of PAPs in feed between pigs and birds and vice versa.


Health and nutrition authorities from European countries and EU- Commission

Health and nutrition authorities have failed to protect the population from the hazards of BSE and have made it possible the disease to keep on spreading all over the word. In France the families of four people which died of the new variant of Creutzfeldt-Jakob disease blame the government of having failed to react properly in the years of 1988 to 1996 causing their death.
According to documents concerning this matter which have been presented by the plaintiffer the French government had knowledge since 1990 of the risk of human BSE-contamination. The government banned the import of beef from Great Britain with delay of 6 years.

There is also a charge against the European Union which did not stopped the trade of animal feed from UK with the Continent in order not to delay the opening of the European Market in 1992. France supported this decision in order to protect her meat industry[23].

On December 6, 2001 the scientific committee which advises the EU-Commission has confirmed that prions of unknown origin are responsible for the transmission of the BSE disease by means of feed and other contaminations and in a small number from the animal mother to its child.[24] tests Such meager statement is a sign of disorientation on regard to BSE.
Since 1995 there were 101 n CJD cases reported.

[25]
Year Reported cases
  of nCJD
1995 3
1996 10
1997 10
1998 18
1999 15
2000 28
Reported total cases of vCJD in humans until 2007 in UK are 158.[26] Reported total cases of vCJD in France until 2007 are 21 [27]


Chronic Wasting Disease CWD

Chronic Wasting Disease in whitetail deer and elk is found in Colorado,Wyoming, Nebraska, Wisconsin and Illinois, Kansas, South Dakota,Montana, Oklahoma,New Mexico, Alberta and Saskatchewan.
It causes spongy holes in the brains of the animals. They slobber, stagger, lose weight and die. There is no cure. The disease belongs to the family of disorders that includes scrapie in sheep, mad cow disease in cattle and Creutzfeldt-Jakob disease in humans.

Research is being done in order to see whether Chronic Wasting Disease can jump from deer to other species such as cattle and even humans through exposure to infectious agents such as venison and velvet antler used in food supplements.[28]
The prions that cause CWD may persist in the environment for years. It is therefore suggested to avoid plowing under the carcasses of animals that have died of scrapie, mad cow disease or other prion disease or use these carcasses in fertilizer because animals may consume contaminated soil while grazing. There is although the possibility that prions in the soil could be absorbed by plants and worms which are consumed by the animals.

Greater potential of CWD-infected deer than elk to transmit the disease to other species [29]

Brent L. Race and colleagues 2007 studied the potential for cross-species transmission of chronic wasting disease (CWD) of deer and elk. According to he researchers CWD prevalence in wild elk is much lower than its prevalence in wild deer. The researchers found that the quantification of prion protein from tonsil and retropharyngeal lymph nodes showed much higher levels of PrPres in deer than in elk, suggesting that CWD-infected deer may be more likely than elk to transmit the disease to other cervids and have a greater potential to transmit CWD to noncervids.

The high presence of PrPres in deer lymphoid tissues suggest that infectivity might also be present in other peripheral tissues such as intestine, kidney, or salivary glands, which could possibly lead to excretion or secretion of infectivity in faeces, urine, or saliva. in confined settings, where animal-to-animal contact increases.

CWD transmission to humans

Earlier studies have not shown any evidence for transmission of CWD to humans. CWD has been transmitted to cattle by intracerebral but not by oral inoculation, and no reports have found that co-pasturing of CWD-infected deer or elk with cattle has resulted in transmission. Raymond and colleagues 2000 [28] found in vitro assays designed to test the susceptibility of humans or cattle to CWD suggested a very low probability of transmission to humans. Raymond suggests that there might be a barrier at the molecular level that should limit the susceptibility of non-cervid species to CWD.

Sheep might cross CWD species barrier

Race and colleagues suggest that among livestock, sheep might be a possible target for CWD infection in appropriate situations such as co-pasturing. Also, a CWD agent from putatively infected sheep could have a host range not usually associated with CWD and might cross species barriers more readily than CWD from cervids. Thus, if CWD continues to expand in deer and elk populations, the possibility of transmission to noncervid species will require continued surveillance.

Natural cross-species transmission of 263 K scrapie in hamster [30]

Transmissible spongiform encephalopathy (TSE) diseases are known to cross species barriers. New TSE diseases have been identified in deer and elk, in domestic cattle, and in humans. The amino acid sequence of the prion protein (PrP) is known to be an influential factor for cross-species transmission of TSE disease to a new host.

Meade-White and colleagues 2009 reported that hamsters, infected with original Syrian hamster 263 K prions, presented profile changes of the PrP amino acid sequences within different hamster species. The authors suggest that the PrP sequences of a new host can change the phenotype presentation of the infecting agent. Identification of cross-species transmission events are thereby very difficult.

Human prion protein polymorphism 171S resistance to murine scrapie [31]

Transmissible spongiform encephalopathies (TSE) or prion diseases are neurodegenerative disorders associated with conversion of normal host prion protein (PrP) to a misfolded, protease-resistant form (PrPres). PrP expression is required for prion disease, and PrP knockout mice are resistant to both infection and disease. PrP gene polymorphisms occur naturally in many species. Polymorphisms in sheep and in mice may influence susceptibility to scrapie infection.
..
Striebel et al 2011 describe the influence of prion disease on a rare human polymorphism PrP N171S using a mouse PrP homolog, PrP-170S. The scrapie strains 22L and ME7 were highly pathogen for PrP 170S mice. Strains RML and 79A produced clinical disease and PrPres formation in only a small subset of mice at very late times. Resistance to infections in mice, but no resistance to infectious prions in vitro suggest that in vivo conversion of PrP-170S by RML and 79A scrapie strains is prevented by PrP molecules expressing certain polymorphisms, factors or conditions not present in vitro.

Prion protein membrane anchoring is necessary for prion infection [32]

According to Klingeborn et al. 2011 a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein is necessary for prion protein PrP to become neuroinvasive. The authors tested various innoculation routes in mice. Prion diseases are transmitted by extracerebral prion infection, anchored PrP are therefore important for the infection to take place.

CWD infection depends on the amino acid sequence of host prions [33]

Chronic wasting disease (CWD) is a prion disease affecting deer, elk, and moose. Race et al. 2011 point out that susceptibility to infections depends on the amino acid sequence of the host prion protein (PrP). The authors found that mice expressing 96GG deer PrP protein were highly succeptible to CWD, but mice which expressed 96SS PrP prion protein were immune to the disease. These data support the assumption that susceptibility to CWD infection depends on the amino acid sequence of host prions.

Humans may be resistant to chronic wasting disease (CWD) of deer, elk and moose [34]

To verify human susceptibility to CWD Race et al. 2009 used cynomolgus macaques and squirrel monkeys as human models. Feeding infectious CWD materials caused the disease in squirrel monkeys but cynomolgus macaques did not diseased. The authors stress that humans are evolutionarily closer to macaques than to squirrel monkeys, suggesting that humans are also resistant to chronic wasting disease.

Chronic wasting disease (CWD) infectious prion materials in deer fat [35]

CWD infectious prion materials are found in central nervous system and lymphoid tissues, with smaller amounts in intestine and muscle of ruminants, and also in fat of mice. Fat of ruminants, such as deer should be considered as CWD infection of other species.

Soil as reservoir of prions [36]

Farm soil is a potential long-term reservoir for BSE infective agents according to findings that point out that prions bind tightly to clay.

Ban of import of all cervids in Oregon

To avoid further spreading of the CWD Oregon has imposed a permanent ban on the import of all live grazing deerlike animals called cervids. allowed are only boned wrapped and cut meat. Not allowed are brainparts, whole heads or spines. Allowed are hides and portions of clean skull plates with antler attached.[37]

History of CWD

mid-1990s: For years the disease remained confined to Colorado and Wyoming.
1996: The disease was found on an elk farm in Saskatchewan
1997 Signs of the disease in an elk farm of South Dakota.
1998: Elk farms of Nebraska were found to be infected, followed by Oklahoma an in subsequent years Montana, Kansas and Alberta followed.
2002: New Mexico, Minnesota Wisconsin and Illinois reported cases of CWD.
The National Institutes of Health researchers warn that prion diseases may be more common than originally thought, raising public health concerns about the practice of giving other farm animals feed made from the byproducts of other animals.

French BSE goat 2002 [38] [39] [40]

Goats can suffer from scrapie, which is a type of TSE (Transmissible Spongiform Encephalopathy), a group of diseases that also includes BSE in cattle. Scrapie has been known for centuries. A goat slaughtered in France in 2002 has a type of TSE which might be BSE. the mouse bioassay (which takes two years to complete) was confirmed on the 28.01.2005.

This TSE was detected in a healthy goat as part of the normal surveillance measures which have been in place in the EU for many years.BSE has never been found under natural circumstances in ruminants other than cattle. Its presence in goats or other ruminants has been viewed as theoretically possible but has never been detected.

Arising from this EU testing programme, a healthy goat slaughtered in 2002 in France was tested at random for TSEs. Now preliminary results indicate that a goat slaughtered in France in 2002 has a type of TSE which might be BSE. It is believed that the goat was infected by feed with BSE prion contaminated meat. As this feed was banned for use in all ruminants, there is no risk of a widespread problem.

Based on these facts, the European Food Safety Authority (EFSA) has advised that goat milk and derived products are unlikely to present any risk of TSE contamination if the milk comes from healthy animals. Currently, as a precautionary measure and following scientific advice, milk and meat from goats which are affected by TSE cannot be used. These rules were in place before the case of BSE in a goat was discovered. As for cattle and sheep, specified risk materials (the tissues most likely to carry infectivity if the disease is present) are also removed from all goats even if there is no infection detected. While it is not possible to say that there is absolutely no risk, any potential risk will be mitigated by the safety measures put in place.

In light of the above, the European Commission advises no change in current consumption of goat milk, cheese and meat.

BSE/TSE Statement 2004 of the EFSA on health risks of the consumption of milk from goats

Since the early 1990s, the BSE/TSE risk for milk and milk products has been discussed by scientific organisations, risk assessment bodies and public health organisations. Research has focused predominantly on the bovine species, while data on small ruminants, particularly goats, are limited. Indeed, epidemiological and experimental data on ruminants so far available have not provided evidence that milk or milk products harbour prion infectivity.

Some research data support the finding that milk, colostrum and tissues of the mammary gland from bovine can be classified in the category of no detectable infectivity. However, based on a number of observations from research data, mainly research concerning sheep, there are indications that infectivity in the milk from small ruminants cannot be totally excluded. In case of mastitis, one could expect an infiltration of potentially infected blood into the milk as the blood-milk barrier may not or only partly exist. But even in the case of absence of mastitis the barrier may not be 100% effective.

From the limited data available today it is concluded that in the light of current scientific knowledge and irrespective of their geographical origin, milk and milk derivatives (e.g. lactoferrin, lactose) from small ruminants are unlikely to present any risk of TSE contamination provided that milk is sourced from clinically healthy animals. Exclusion of animals with mastitis is considered to reduce the potential risk. Further assurance of healthy milk could include milk tests for total somatic cell counts indicative of inflammation.

Difficulties with somatic cell count

The EFSA in its statement of 2005 enumerates some of the difficulties concerning somatic cell count accuracy of goat milk: [41] The panel concluded in 2005 [41] that due to the high variability of SCC in goat milk, even in healthy animals, SCC cannot be relied on neither as a specific indicator for TSE risk nor as an indicator of udder health. It is recommended to continue the increased surveillance in goats and to initiate additional research that would allow for a Quantitative Risk Assessment in goats. The above recommendations should be extended to include sheep.

BSE in SwedenOne cow was tested positive for BSE in Sweden in 2006.The Swedish Board of Agriculture (BOA) believes that the cow had been fed meat and bone meal by mistake. Not all safety routines were in place during the first years of the infected cow's life.

The animal was probably infected about ten years ago. An investigation has started in order to find what feedingstuffs the animal may have eaten during its lifetime. This investigation will also find so-called risk animals on the farm, for instance animals in the same age bracket that have eaten the same feedingstuffs. [42]

In the EU, BSE incidents have been falling dramatically since 1992. Extensive testing and controls programmes are responsible for the decline of incidences of the disease from 37,280 cases in 1992 to recent figures reported by the OIE. The favorable development led the EC to adopt a roadmap in July of 2005, with the aim of softening restrictions and reducing testing costs.

The World Organisation for Animal Health published the details of BSE in countries that reported cases in 2004. According to this report Ireland found 126 cases of BSE in its cattle in 2004, compared with 137 found in Spain. The UK had the highest incidence of BSE cases in the world in 2004 with 343 cases confirmed, followed by Spain, Ireland. Portugal was fourth in the BSE league, reporting 92 cases in 2004, followed by Germany with 59 cases. France reported 54 cases of BSE in the same year. [43]

Production process for gelatine [44]

According to the Corrigendum to Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29April 2004 laying down specific hygiene rules for food of animal origin, the production process for gelatine must ensure that:

1. For the production of gelatine intended for use in food, the following raw materials may be used:
(a) bones;
(b) hides and skins of farmed ruminant animals;
(c) pig skins;
(d) poultry skin;
(e) tendons and sinews;
(f) wild game hides and skins;
and
(g) fish skin and bones.

2. The use of hides and skins is prohibited if they have undergone any tanning process, regardless of whether this process was completed.

3. Raw materials listed in point1(a) to(e) must derive from animals which have been slaughtered in a slaughterhouse and whose carcases have been found fit for human consumption following ante-mortem and post-mortem inspection or, in the case of hides and skins from wild game, found fit for human consumption.

4. Raw materials must come from establishments registered or approved pursuant to Regulation (EC) No 852/2004 or in accordance with this Regulation.

5. Collection centres and tanneries may also supply raw material for the production of gelatine intended for human consumption if the competent authority specifically authorises them for this purpose and they fulfil the following requirements.

(a) They must have storage rooms with hard floors and smooth walls that are easy to clean and disinfect and, where appropriate, provided with refrigeration facilities.

(b) The storage rooms must be kept in a satisfactory state of cleanliness and repair, so that they do not constitute a source of contamination for the raw materials.

(c) If raw material not in conformity with this chapter is stored and/or processed in these premises, it must be segregated from raw material in conformity with this chapter throughout the period of receipt, storage, processing and dispatch.

Chapter II: Transport and Storage of Raw Materials

In place of the identification mark provided for in Annex II, Section I, a document indicating the establishment of origin and containing the information set out in the Appendix to this Annex must accompany raw materials during transport, when delivered to a collection centre or tannery and when delivered to the gelatine-processing establishment.

Raw materials must be transported and stored chilled or frozen unless they are processed within 24 hours after their departure. However, degreased and dried bones or ossein, salted, dried and limed hides, and hides and skins treated with alkali or acid may be transported and stored at ambient temperature.

Chapter III: Requirements for the Manufacture of Gelatine
1. The production process for gelatine must ensure that:

(a) all ruminant bone material derived from animals born, reared or slaughtered in countries or regions classified as having a low incidence of BSE in accordance with Community legislation is subjected to a process which ensures that all bone material is finely crushed and degreased with hot water and treated with dilute hydrochloric acid (at minimum concentration of 4% and pH 12.5) for a period of at least 20 days with a sterilisation step of 138 to 140C ° during four seconds or by any approved equivalent process;
and

(b) other raw material is subjected to a treatment with acid or alkali, followed by one or more rinses. The pH must be adjusted subsequently. Gelatine must be extracted by heating one or several times in succession, followed by purification by means of filtration and sterilisation.

2. If a food business operator manufacturing gelatine complies with the requirements applying to gelatine intended for human consumption in respect of all the gelatine that it produces, it may produce and store gelatine not intended for human consumption in the same establishment.

Chapter IV: Requirements for Finished Products
Food business operators must ensure that gelatine complies with the residue limits set out in the following table:

Residue Limit
As 1 ppm
Pb 5 ppm
Cd 0,5 ppm
Hg 0,15 ppm
Cr 10 ppm
Cu 30 ppm
Zn 50 ppm

Reduction of BSE tests on US cows [45]

Over the last few years, a type of Acquired CJD called variant (vCJD) has been identified in young people. vCJD has been linked to ingestion of beef tainted with BSE (bovine spongiform encephalopathy), most cases have occurred in the United Kingdom. Testing cows being slaughtered helped to reduce the risk of vCJD.

However, according to Florence's Newsletter, the USDA tests so few cows it would be impossible for anyone to know how prevalent U.S. BSE really is. Cattle testing was increased from 40,000 per year to 375,000 for an 18 month period following the discovery - there are 35 million cattle slaughtered for the U.S. food supply each year. The Secretary of Agriculture Mike Johanns was asked last July by a commission leaded by CDJ Disease Foundation that the increased number of BSE testing should not be cut back but instead that it be increased. One week after this petition USDA cut back to the previous 40,000.

In a letter to Florence at the Creutzfeld-Jacobs Disease Foundation dated October 3, 2006 Mr. Johanns stated.... "With regard to USDA's activities, it is important to understand ...USDA's BSE surveillance is being conducted not as a food safety measure but rather as a monitoring effort designed to evaluate the effectiveness of the United States' BSE safeguarding measures with respect to animal health".

According to Florence it is difficult to understand how human risk from infected meat takes a back seat to what appears to be a policy benefiting specific special interest groups.

A statement released end May2007 reported that Japan and South Korea will soon be opening their borders to US cattle again based on the U.S. upgraded rating from the OIE (World Organization for Animal Health) from "possible risk" to "controlled risk".

The USDA's Chief Veterinary Office Dr. Ron DeHaven serves as the U.S. official delegate to the OIE. Through the OIE decision the USDA is now able to avoid accountability at all costs, even those directly related to human lives.

The role of meat and bone meal (MBM) in the epidemiology of BSE [46]

Mathilde Paul and colleagues 2007 studied the role of meat and bone meal (MBM), animal fat and dicalcium phosphate (DCP) after the feed ban on the risk for BSE epidemics.

In France, meat-and-bone meal (MBM) has been banned from cattle feed since July 30, 1990. However, through January 1, 2007, 957 cases of bovine spongiform encephalopathy (BSE) have been detected in cattle born after the ban.

Meat bone meal (MBM)

According to the authors the source of infection in cattle born after the MBM ban still involves MBM. The BSE agent may have entered cattle feed by cross-contamination with feed for monogastric species (pigs and poultry) in which MBM was still authorized until November 2000. Cross-contamination could have occurred within factories, during feed delivery to the farm, or on mixed farms that have cattle and pigs or poultry.

The authors raise the question of effectiveness of the ban that was initially restricted to bovines and belatedly extended to other species to reduce cross-contamination.

The role of MBM as a source of BSE after the ban of MBM for cattle is well documented through cross-contamination in feed factories. The authors found that the total ban of MBM for farm animals in November 2000 was essential for controlling the spread of BSE.

Other animal by products

Animal dicalcium phosphate (DCP)

According to Paul and colleagues, together with other studies say that the implication of animal DCP as a source of BSE, if it existed, should have been marginal.

In contrast, a risk analysis by the European Food Safety Agency [2] considers the potential role of animal DCP in cattle infection as to be of the same order of magnitude as the residual risk from cross-contamination with MBM.

Animal fat in milk replacers

This study cannot exclude a minor effect of animal fat in milk replacers because of the solubility of prions and the possible contamination with protein impurities by contact with other infectious materials at the slaughterhouse. Animal fat is incorporated in cattle feed in milk replacer and in proprietary concentrates.

The authors point to the fact that in current context of the decreasing epidemic, economic pressure is increasing to release the ban of MBM in feed for monogastric species.

Detection of prion infection in vCJD disease associated with the ingestion of BSE food [47]

Variant Creutzfeldt-Jakob disease (vCJD) is a fatal neurodegenerative disorder originating from exposure to bovine-spongiform-encephalopathy-like prions. This disease has a long and clinically silent incubationsposing and is a risk to others via blood transfusion, blood products, organ or tissue grafts, and contaminated medical instruments. The authors report the development of an assay for detection dormant infections. It is based on a solid-state binding matrix to capture and concentrate disease-associated prion proteins coupled with direct immunodetection of this surface-bound material. The authors stress that it is a prototype blood test for diagnosis and can be further developed to allow large-scale screening tests for asymptomatic vCJD prion infection.

People become infected by BSE prions by eating food containing material from BSE-infected cattle, although other sources of exposure are possible. Much of the UK population born before 1996 (when rigorous measures to limit exposure were enforced) have potentially been exposed to BSE-contaminated food and the number of people who may carry the infection but remain healthy is unknown. [48]

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