Who discovered mad cow disease: Mad Cow Disease Fast Facts

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Mad Cow Disease Fast Facts

Eating contaminated meat or other products from cattle (excluding dairy products) with BSE is thought to be the cause of vCJD.

BSE is passed between cows through the practice of recycling bovine carcasses for meat and bone meal protein, which is fed back to other cattle.

Both mad cow disease and vCJD are fatal.

Symptoms of vCJD involve psychiatric symptoms and behavioral changes, movement deficits, memory disturbances and cognitive impairments.

BSE Statistics (Cattle)

(source: CDC)
BSE cases in North America 1993-August 2018: 26 cases confirmed, 20 in Canada, and six in the United States. One of the infected cows that died in the United States was born in Canada. One of the infected Canadian cows was imported from the United Kingdom.

vCJD Statistics (Humans)

(source: CDC)
Since 1996, 231 vCJD cases have been identified in 12 countries:
United Kingdom – 178
France – 27
Spain – 5
Ireland – 4
United States – 4
Italy – 3
The Netherlands – 3
Portugal – 2
Canada – 2
Japan – 1
Saudi Arabia – 1
Taiwan – 1

Timeline

1986 – Mad cow disease is first discovered in the United Kingdom. From 1986 through 2001, a British outbreak affects about 180,000 cattle and devastates farming communities.

January 1993 – The BSE epidemic in Britain reaches its peak with almost 1,000 new cases being reported per week.

1996 – The first case of vCJD is reported.

1996-1999 – The European Union bans British beef. France continues the ban for an additional three years.

May 20, 2003 – Canada’s first case of mad cow disease is confirmed in an 8-year-old cow in Alberta. Canadian officials say the cow did not enter the food chain.

May 21, 2003 – Mexico, Japan and South Korea join the United States in temporarily banning Canadian beef.

December 23, 2003 – The US Department of Agriculture confirms the first case of mad cow disease in the United States. The infected cow is discovered on a farm in Washington State in early December. Japan, China and South Korea stop the importation of US beef. The infected cow was born in Canada, in April 1997 – just four months before the United States and Canada began banning the use of brain and spinal cord tissue in cattle feed.

January 9, 2004 – The USDA says it will begin destroying about 130 cattle that were “herd mates” of the cow that tested positive for the first-ever US case of mad cow disease.

January 26, 2004 – New safeguards against mad cow disease are announced by the Food and Drug Administration. They include banning chicken waste from cattle feed and barring restaurant meat scraps from being used in animal feed.

January 28, 2004 – The Commodity Futures Trading Commission launches an investigation into whether some commodity futures market players may have known about the first US case of mad cow disease before it was announced to the public.

June 20, 2004 – Charlene Singh, the first person known to live in the United States with vCJD, dies.

January 2, 2005 – Canadian health authorities confirm that test results have identified a 10-year-old dairy cow in Alberta as having mad cow disease. This is Canada’s second case of BSE in two years.

June 24, 2005 – The second US case of BSE is confirmed.

March 13, 2006 – The third US case of BSE is confirmed after an Alabama cow tests positive.

September 5, 2008 – Canadian scientists announce a discovery that paves the way for diagnostic testing of live cattle, rather than postmortem.

September 13, 2008 – An Alabama research study shows that mad cow disease can sometimes be caused by genetic mutations.

March 10, 2009 – An anti-malaria drug known as quinacrine, which had reportedly shown promise against mad cow disease, is found to have no effect on the disease, according to a British medical study.

March 14, 2009 – The US government permanently bans the slaughter of cows too sick or weak to stand on their own, seeking to further minimize the contraction of mad cow disease.

April 24, 2012 – The USDA confirms the fourth case of BSE, found in a dairy cow from central California. The announcement maintains that the cow was never presented for slaughter for human consumption and poses no risk.

March 2014 – After 15 years, the United States lifts the ban on beef from the European Union, pending inspections.

June 11, 2014 – The USDA announces a recall of 4,000 pounds of beef; a spokesperson cites “an abundance of caution.” The meat comes out of the Fruitland American Meat processing plant in Jackson, Missouri.

March 24, 2016 – France confirms the first case of BSE since 2011.

October 18, 2018 – Scotland confirms an “isolated case” of mad cow disease has been discovered on a farm in Aberdeen.

A brief history of mad cow disease

EDMONTON – Bovine spongiform encephalopathy, commonly known as mad cow disease, was first identified in Britain in 1986. The Canadian Food Inspection Agency announced Friday a case of mad cow disease has been confirmed in a beef cow in Alberta, the first case in Canada since 2011.

What is mad cow disease?

It is a progressive, fatal neurological disease in cattle, believed to be caused by prions — irregular protein particles that are hard to destroy. Because they can survive being cooked, prions can be passed on to humans who ingest infected tissue or food products containing such tissue.

By 1996, BSE had been linked to a variant form of Creutzfeldt-Jakob disease, a rare, degenerative brain disorder that leads to dementia and death. Canada’s only two cases of the human form of mad cow disease were both acquired overseas.

How many cases have been confirmed in Canadian cows, prior to this new one?

Canada has officially had 18 cases of BSE, including 13 from Alberta. The last reported case was detected in February 2011. In none of these cases did the animals enter the human food supply or animal feed chain.

What happens when a cow gets this disease?

In BSE, the prions create microscopic holes in the animal’s brain tissue that cause erratic behaviour, hence the nickname mad cow disease.

What happened during the mad cow crisis of 2003?

In January 2003, a six-year-old Black Angus at a grain farm and feedlot near Wanham, in Alberta’s Peace Country, died. It was sent to a local abattoir where it was condemned, then the carcass was sent to a rendering plant. The head was sent to a provincial laboratory in Edmonton where it sat for three-and-a-half months before it was tested, revealing the cow had BSE. The case was announced to the public on May 20, 2003. More than 30 countries closed their borders to Canadian beef imports, including the United States. At the height of the crisis, the economy was losing $11 million dollars a day, according to the federal and provincial governments of the time.

Read more on the latest case of mad cow disease: http://edmjr.nl/173Fvtr

Scientists reveal the possible origin of the “mad cow” disease

· A team of scientists demonstrates that bovine spongiform encephalopathy (BSE) could have originated from atypical scrapie prions, a neurodegenerative disease that appears spontaneously in sheep and goats.

· These infectious agents would have been transmitted to the cows when they were fed with meat meal and sheep bones infected with prions, a practice currently prohibited.

· 226 people suffered the variant of Creutzfeldt-Jackob disease after consuming beef contaminated with prions.

In the late 1990s, Europe suffered one of the worst food crises due to the disease of “crazy cows.” In the United Kingdom, about 200,000 cows presented symptoms such as tremor, changes in behavior and loss of balance, until death. In Spain, they were about a thousand. Some of the people who ingested products derived from “mad cow” suffered the variant of Creutzfeldt-Jackob disease, a neurodegenerative pathology without cure. The number of people affected worldwide by this disease was 226, five of which from Spain. The hypothesis that was raised was that the first cows had become ill because they had consumed feed made from sheepmeat and meat meal contaminated with classic scrapie prions, a fatal degenerative disease that affects the nervous system of sheep and goats and contagious among animals of the same flock. Until today, several studies have ruled out this initial hypothesis.

Now, a study led by the ENVT-INRA center of Tolouse, the Animal Health Research Center (IRTA-CReSA) and the Animal Health Research Center (INIA-CISA), with the participation of the Autonomous University of Barcelona (UAB) and of the University of Zaragoza (UNIZAR), reveals that the infectious agent responsible for bovine spongiform encephalopathy or “mad cow” disease could come from atypical scrapie, another type of prion involvement of sheep and goats. This prion disease was discovered in 2003 and unlike the classic scrapie appears spontaneously, in isolated cases and does not spread among the herd.

The study’s experiments, published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) journal, demonstrate for the first time that when atypical scrapie prions are transmitted from one species to another they change structure and their ability to infect evolves. “It is a relevant result because it gives us more clues about how a prion disease of sheep would have passed to cows and then to people, becoming a zoonotic disease,” says Enric Vidal, veterinarian and researcher of IRTA-CReSA.

PRIOCAT laboratory. /IRTA-CReSA (CC BY-NC 2.0)

Prions are proteins found in the body of animals and people naturally, mainly in the brain. The problem is that when they change their structure and cause other proteins to do so, they can become neurodegenerative. “This change of structure can be due to genetic causes, it can also happen spontaneously or by ingesting contaminated proteins. On the other hand, there have been some cases of accidental inoculation by manipulation of work tools, for example, in the laboratory or in animal surgeries”, explains Martí Pumarola, professor of the Department of Medicine and Animal Surgery of the Faculty of Veterinary Medicine of the UAB . Currently, there are still cases of people with Creutzfeldt-Jackob disease – different from the variant caused by crazy cows – as well as animals sick with prions spontaneously. These cases are no longer due to the intake of contaminated food because since the crisis of the “mad cows” the use of feed made from ruminant protein flours was prohibited.

So far there is no treatment or vaccines for human or animal prion diseases, but the study authors say that this finding will improve the risk assessment of these diseases in the field of animal health and public health. “Now we have verified that the atypical scrapie is capable of giving rise to bovine spongiform encephalopathy in cows, which we did not know until now. While the prohibition of these feeds made with sheep derivatives remains active we will not have new cases of” crazy cow “because intake,” explains Enric Vidal.

A decade of study with international collaboration

Experiments have been performed with transgenic mouse models – mice with cow genes – to see how prions of atypical scrapie affect them. The prions used in the study came from real cases diagnosed in sheep from Spain, France, Portugal and Norway. The tests have been carried out thanks to the PRIOCAT laboratory of the Biocontainment Unit of the IRTA-CReSA center. This biosafety level 3 infrastructure forms the Network of Hight Biosafety Laboratories (RLASB), a Singular Scientific and Technical Infrastructure of Spain (ICTS). PRIOCAT carries out the diagnosis of animal prion diseases of Catalonia within the program of control and eradication of transmissible spongiform encephalopathies (EETs), commissioned by the Department of Agriculture, Livestock, Fisheries and Food and the Department of Health of the Government of Catalonia.

The study has had the collaboration of other research centers in Norway, Portugal and the United Kingdom. It has had European FEDER funds from the INTERREG-POCTEFA cross-border program through the COTS project, with COTSA and Transprion, which currently make up the RedPRION network (EFA148/16), a group of different research groups for these diseases in Catalonia, Aragon, the Basque Country and southern France. It has also had funds from the La Marató de TV3 Foundation (Project 201821-30-31-32 Evaluation of the public health risk of atypical and emerging prions) of the edition of Infectious Diseases, in this project the zoonotic potential of ‘these sheep prions passed through the bovine species is being assessed by bioassays in humanized transgenic mice.

Article de referència: Alvina Huor*, Juan Carlos Espinosa*, Enric Vidal*, Hervé Cassard, Jean-Yves Douet, Séverine Lugan, Naima Aron, Alba Marín-Moreno, Patricia Lorenzo, Patricia Aguilar-Calvo, Juan Badiola, Rosa Bolea, Martí Pumarola, Sylvie L. Benestad, Leonore Orge, Alana M. Thackray, Raymond Bujdoso, Juan Maria Torres, and Olivier Andréoletti (2019). The emergence of classical BSE from atypical/Nor98 scrapie. Proceedings of the National Academy of Sciences of the United States of America (PNAS).

‘Mad cow disease’ case confirmed in Alberta

May 20, 2003 (CIDRAP News) – Postmortem tests have confirmed that a cow from an Alberta farm had bovine spongiform encephalopathy (BSE), or mad cow disease, Canadian officials announced today. The news marked the first known BSE case in North America since another Alberta case was found in 1993.

The US Department of Agriculture (USDA) immediately announced a temporary ban on imports of Canadian cattle, beef, and beef products. “USDA is placing Canada under its BSE restriction guidelines and will not accept any ruminants or ruminant product from Canada pending further investigation,” Agriculture Secretary Ann Veneman stated.

The case was detected through Canada’s regular BSE surveillance program, Alberta and Canadian federal officials said in a news release. “Alberta agriculture officials tested a cow that had been condemned at slaughter and removed from the food system,” officials said. The carcass was sent to a rendering plant.

An Alberta laboratory and the Canadian Food Inspection Agency (CFIA) tested brain tissue from the 8-year-old cow May 16 and 18, respectively, and found possible signs of BSE, Canadian officials said. “The CFIA sent specimens to the World Reference Laboratory at Weybridge, United Kingdom, which has verified the presence of BSE,” the statement said. The cow came from a northern Alberta ranch and was slaughtered Jan 31 because of suspected pneumonia, the Associated Press reported.

“The CFIA and the Province of Alberta are investigating the animal’s origin and how its remains were processed,” Canadian officials said in their news release. “Information suggests that the risk to human health and the possibility of transmission to other Canadian cattle from this case are extremely low.”

The Alberta farm has been quarantined and the 150-head herd from which the cow came will be destroyed after necessary testing is completed, the statement said. “Any additional herds that are found to be at risk as a result of the investigation will also be depopulated,” officials said.

Veneman said the USDA is sending a technical team to Canada to help in the investigation. “Information suggests that risk to human health and the possibility of transmission to animals in the United States is very low,” she said.

No BSE case has ever been identified in the United States. The previous BSE case in Alberta was found in 1993 in a cow imported from Britain, according to AP and Canadian Press reports. The herd was destroyed and no further cases were identified.

A BSE outbreak occurred in British cattle herds starting in 1986, apparently because cattle were fed with fodder that contained protein from infected animals. Eating beef from BSE-infected cattle is believed to be the cause of variant Creutzfeldt-Jakob disease (vCJD), a fatal brain disease in humans. A number of vCJD cases were diagnosed in the Britain in the 1990s.

The United States in 1989 banned the importation of cattle, sheep, and goats and most related products from countries that have BSE or are considered to be at risk for BSE. And in 1997 the US banned the use of most mammalian protein in feed intended for cows and other grazing animals.

In a Canadian Press report, Debbie Barr, a CFIA veterinarian, said that tracing the infected cow’s history is crucial. She said the cow had been on the Alberta farm the past 3 years, but its whereabouts before that were not yet known.

If the cow was born and raised in Canada and was not fed any imported feed, that could suggest a problem with contaminated feed in Canada, said Wayne Martin, an epidemiologist at the Ontario Veterinary College in Guelph, Ont. Martin was quoted in the Canadian Press report.

See also:

Alberta government news release
http://www.gov.ab.ca/acn/200305/14425.html

Agriculture Secretary Ann Veneman’s statement
http://www.usda.gov/documents/NewsReleases/2003/05/0166.doc

British duo probes origin of mad cow disease

Did human remains in food spawn the infection in cattle?

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Did British cows eat remains of humans with brain disease?
Credit: © Punchstock

Human remains in cattle feed could have caused the first case of mad cow disease, two UK researchers propose. The hypothesis seeks to answer lingering questions about the fatal infection, which has affected 180,000 cows in Britain alone since the mid-1980s, and has gone on to cause more than 100 deaths in humans.

Alan Colchester of the University of Kent and his daughter Nancy Colchester, of the University of Edinburgh, point out that during the 1960s and 1970s Britain imported hundreds of thousands of tonnes of whole and crushed bones and animal carcasses. These were used for fertilizer and to feed livestock.

Nearly 50% of these imports came from Bangladesh, where peasants gathering animal materials may have also picked up human remains, the researchers say.

Other experts in the field view the idea with scepticism, saying that proof remains circumstantial. “The argument isn’t very compelling because there’s no smoking gun evidence,” says Surachai Supattapone, an expert in infectious diseases at Dartmouth Medical School in Hanover, New Hampshire.

Transmissible spongiform encephalopathies (TSEs) are a group of fatal neurodegenerative diseases that affect mammals. Yet until 1986 no such illness had been spotted in cattle.

Once recognized, bovine spongiform encephalopathy (BSE) became widely known as ‘mad cow disease’. The incidence of the disease then rocketed, peaking in late 1992.

Tests indicated misshapen prion proteins in the brains of the cows as the source of the problem. And when authorities banned the practice of recycling animal remains into cattle feed the number of sick livestock began to drop.

But experts continue to puzzle over how BSE arose in the first place.

One of the most widely believed theories is that prions responsible for sheep scrapie got incorporated into cattle feed. Scientists argue that ingested scrapie prions radically altered the normal, analogous proteins in one cow, which then developed the first case of BSE.

But the Colchesters point out that cows have been exposed to scrapie for 70 years, so it is hard to explain why BSE emerged only recently.

They propose that a more likely source is recent exposure to human remains carrying sporadic Creutzfeldt-Jakob Disease (CJD), a TSE thought to arise spontaneously in people.

Religious customs in Bangladesh and surrounding areas mean that many corpses are disposed of in rivers. People may have collected remnants from such bodies when foraging for animal carcasses, the Colchesters argue in The Lancet¹. Any prions in these corpses might then have caused mad cow disease.

Experts agree that the theory needs to be checked. More information needs to be collected, they say, about the number of deaths from CJD in the Indian subcontinent, what happened to the bodies, and whether prions could have been transmitted in the way proposed. When human sporadic CJD prions were injected into mice in previous studies, the mice did not become ill².

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Khamsi, R. British duo probes origin of mad cow disease.
Nature (2005). https://doi.org/10.1038/news050829-17

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BSE disaster: the history | New Scientist

By Claire Ainsworth and Damian Carrington

A few days before Christmas 1984, vet David Bee was called to Stent Farm in Sussex to examine a sick cow with strange symptoms – its back was arched and it had lost weight.

Within six weeks, cow 133 was dead, having developed head tremors and a loss of coordination. Seven months later, the UK Central Veterinary Laboratory diagnosed spongiform encephalopathy. By this time, other cows were also showing symptoms. The epidemic had begun.

Four herds had been affected when the Central Veterinary Office alerted the Ministry of Agriculture, Fisheries and Food (MAFF) in June 1987.

Nearly a year later, the government set up a working party chaired by Oxford University professor of zoology, Richard Southwood, to investigate bovine spongiform encephalopathy (BSE) and any implications for human health.

Cattle cannibalism

Shortly after this, the government banned the feeding of cattle with protein derived from other cattle and sheep. Epidemiological studies done by MAFF scientists had pinpointed this cannibalism as being the only plausible cause of BSE. By this time it was known that BSE was a prion disease but whether the infective prion came from scrapie-infected sheep or another source is still not known.

The Southwood committee reported in February 1989, recommending a ban on the use of bovine offal in baby foods. The British government went further, and in November 1989, banned the use of specified bovine offals (SBO) in all human food.

In October of the previous year, BSE was shown to be transferable to mice, through a brain-to-brain injection of infected material. But, making assumptions based on past experience with scrapie, the Southwood committee decided that it was unlikely that BSE could be passed to humans. However, the report added&colon; “If our assessments of these likelihoods are incorrect, the implications would be extremely serious.”

Photo: Nigel Dickinson/Still Pictures

After the Southwood report, the government instituted a mass slaughter programme for all cows suspected of having BSE. However, farmers were only given 50 per cent compensation for each confirmed case. Critics have argued that this policy led to infected animals being sold illegally for human consumption until 1990, when 100 per cent compensation was offered.

Mad cow – crazy cat

The first hint that humans could be affected came in 1990, when a Siamese cat called Max fell ill with the feline version of BSE. That same year, scientists showed that the disease could be orally transmitted to mice.

The assumption that BSE could not cross the species barrier was proving increasingly uncertain. Despite this, the government assured the public that British beef was safe to eat, with agriculture minister John Gummer famously feeding his daughter a beefburger.

Cases of BSE peaked between 1992 and 1993, with 3 in every 1000 cows affected. The incidence began to decline in 1993, and in March, the government’s Chief Medical Officer repeated the 1990 assurance that beef was safe. Research in 1994 showed that cattle could contract BSE orally. but it was in 1995 that the human tragedy began.

Premature death

In May, 19-year-old Stephen Churchill died after an illness resembling Creutzfeldt-Jakob Disease. CJD is a rare and sporadic brain disease. It affects up to 60 people a year in Britain, but they are usually over 55 years old.

Two other deaths occurred that year, showing similar symptoms to Churchill. James Ironside, a pathologist at the National CJD Surveillance Unit, discovered that the brains of these patients showed unusual spongiform symptoms. He named the condition variant CJD (vCJD).

In November 1995, MAFF scientists informed the Spongiform Encephalopathy Advisory Committee (SEAC), which had been set up in May 1990, that spot checks on abattoirs had revealed that the SBO ban was not being strictly enforced. Dressed carcasses in some abattoirs were found to contain small pieces of spinal cord.

This meant that potentially highly infective material could have been entering the human food chain for six years after the ban designed to prevent it was introduced. Robert Will, the deputy chair of SEAC, told the BSE inquiry&colon; “I was appalled.”

Beef ban

By 1996, there had been a total of eight cases of vCJD, mostly in young people. SEAC advised the government in March that the most likely cause of this new disease was eating beef products contaminated with the BSE agent. The Health Secretary, Stephen Dorrell, related the information to Parliament on the same day.

Almost immediately the European Union banned all exports of British beef. The British government introduced new measures in an attempt to contain BSE, such as a selective cull of cattle reared alongside those with BSE between 1989 and 1993.

To date, there have been 84 confirmed and probable vCJD cases in Britain. But scientists are still waiting to see whether this will snowball into a large epidemic, killing hundreds of thousands of people, or whether it will be confined to a few hundred cases.

BSE Surveillance Information Center | USDA

Introduction

USDA conducts surveillance for Bovine spongiform encephalopathy (BSE), referred to as “mad cow disease”, in cattle to determine if, and at what level, the disease is present in the U.S. cattle population. Our surveillance program allows us to assess any change in the BSE disease status of U.S. cattle, and identify any rise in BSE prevalence in this country. Identifying any changes in the prevalence of disease allows us to match our preventive measures – feed ban for animal health, and specified risk material removal for public health – to the level of disease in U.S. cattle.

It is the longstanding system of interlocking safeguards, including the removal of specified risk materials – or the parts of an animal that would contain BSE – at slaughter and the FDA’s ruminant-to-ruminant feed ban that protect public and animal health from BSE.

Why did USDA decrease the number of samples per year in 2006?

After the first confirmation of BSE in an animal in Washington State in December 2003, USDA evaluated its BSE surveillance efforts in light of that finding. We determined that we needed to immediately conduct a major surveillance effort to help determine the prevalence of BSE in the United States. Our goal over a 12-18 month period was to obtain as many samples as possible from the segments of the cattle population where we were most likely to find BSE if it was present. This population of cattle was exhibiting some signs of disease. We conducted this enhanced surveillance effort from June 2004 – August 2006. In that time, we collected a total of 787,711 samples and estimated the prevalence of BSE in the United States to be between 4-7 infected animals in a population of 42 million adult cattle. We consequently modified our surveillance efforts based on this prevalence estimate to a level we can monitor for any potential changes, should they occur. Our statistical analysis indicated that collecting approximately 40,000 samples per year from the targeted cattle population would enable us to conduct this monitoring.

Why is USDA “only” testing 25,000 samples a year?

USDA’s surveillance strategy is to focus on the targeted populations where we are most likely to find disease if it is present. This is the most effective way to meet both OIE and our domestic surveillance standards. After completing our enhanced surveillance in 2006 and confirming that our BSE prevalence was very low, an evaluation of the program showed that reducing the number of samples collected to 40,000 samples per year from these targeted, high risk populations would allow us to continue to exceed these standards. In fact, the sampling was ten times greater than OIE standards. A subsequent evaluation of the program in 2016 using data collected over the past 10 years showed that the surveillance standards could still be met with a further reduction in the number of samples collected by renderers and 3D/4D establishments which have a very low OIE point value because the medical history of these animals is usually unknown. Therefore, in 2016, the number of samples to be tested was reduced to 25,000 where it remains today.

How can USDA find every case of BSE in the United States when you are only testing 25,000 animals?

The goal of our BSE surveillance program, even under the enhanced program, has never been to detect every case of BSE. Our goal is determine whether the disease exists at very low levels in the U.S. cattle population, and we do this by testing those animals most likely to have BSE. It is the longstanding system of interlocking safeguards, including the removal of specified risk materials – or the parts of an animal that would contain BSE – at slaughter and the FDA’s ruminant-to- ruminant feed ban that protect public and animal health from BSE.

Why didn’t USDA continue to test animals at the enhanced surveillance level?

USDA’s 2004-2006 enhanced surveillance program was initiated in response to the first detection of BSE in the United States and was designed to detect the overall prevalence of the disease in this country. This required a very intensive effort and it allowed us to estimate extremely low prevalence levels of disease. Once that prevalence level was determined, USDA modified its testing levels to monitor any changes in the level of disease. Our current testing of approximately 25,000 targeted animals a year allows USDA to detect BSE at the very low level of less than 1 case per million adult cattle, assess any change in the BSE status of U.S. cattle, and identify any rise in BSE prevalence in this country.

Is USDA’s surveillance program a food safety or public health measure?

The primary, and most effective, food safety or public health measure is the removal of specified risk materials (SRMs) – or the parts of an animal that would contain BSE – from every animal at slaughter. USDA’s BSE surveillance program is not a food safety measure; it is an animal health monitoring measure. However, it does support existing public health and food safety measures. By allowing us to monitor the level of disease in the US cattle population, we can help determine the appropriate level of public health and animal health measures required, and whether they should be increased or decreased.

Why doesn’t USDA test every animal at slaughter?

There is currently no test to detect the disease in a live animal. BSE is confirmed by taking samples from the brain of an animal and testing to see if the infectious agent – the abnormal form of the prion protein – is present. The earliest point at which current tests can accurately detect BSE is 2 to 3 months before the animal begins to show symptoms, and the time between initial infection and the appearance of symptoms is about 5 years. Therefore, there is a long period of time during which current tests would not be able to detect the disease in an infected animal.

Since most cattle are slaughtered in the United States at a young age, they are in that period where tests would not be able to detect the disease if present. Testing all slaughter cattle for BSE could produce an exceedingly high rate of false negative test results and offer misleading assurances of the presence or absence of disease.

Simply put, the most effective way to detect BSE is not to test all animals, which could lead to false security, but to test those animals most likely to have the disease, which is the basis of USDA’s current program.

What animals are USDA testing in the surveillance program? These are random samples at slaughter, aren’t they?

No. USDA’s BSE surveillance program is specifically targeted to the population most likely to have the disease, if it is present. This population is NOT clinically healthy animals that would be presented for slaughter. Rather, it includes animals that have some type of abnormality, such as central nervous system signs; non-ambulatory, or a “downer”; emaciated; or died for unknown reasons. Because these animals would not pass the required ante-mortem inspection requirements at slaughter for human consumption, we collect the majority of our samples at facilities other than slaughter facilities – at rendering or salvage facilities, on-farm, at veterinary clinics or veterinary diagnostic laboratories. With this targeted approach, we can monitor the presence of disease in the US cattle population in a much more efficient and meaningful way. The key to surveillance is to look where the disease is going to occur.

Key Points: BSE Ongoing Surveillance Plan

Note: This Fact Sheet is based on the USDA Animal and Plant Health Inspection Service (APHIS) Bovine Spongiform Encephalopathy (BSE) Ongoing Surveillance Plan, July 20, 2006. To learn more, read the complete BSE Ongoing Surveillance Plan (PDF, 187 KB).

KEY POINTS

In addition to a stringent feed ban imposed by the Food and Drug Administration in 1997 as well as the removal of all specified risk material which could harbor BSE, USDA has a strong surveillance program in place to detect signs of BSE in cattle in the United States. In fact, we test for BSE at levels greater than World Animal Health Organization standards. The program samples approximately 25,000 animals each year and targets cattle populations where the disease is most likely to be found. The targeted population for ongoing surveillance focuses on cattle exhibiting signs of central nervous disorders or any other signs that may be associated with BSE, including emaciation or injury, and dead cattle, as well as non-ambulatory animals. Samples from the targeted population are taken at farms, veterinary diagnostic laboratories, public health laboratories, slaughter facilities, veterinary clinics, and livestock markets.

USDA’s National Veterinary Services Laboratories (NVSL) in Ames, IA, along with contracted veterinary diagnostic laboratories, use rapid screening tests as the initial screening method on all samples. Any inconclusive samples undergo further testing and analysis at NVSL.

NOT A FOOD SAFETY TEST

BSE tests are not conducted on cuts of meat, but involve taking samples from the brain of a dead animal to see if the infectious agent is present. We know that the earliest point at which current tests can accurately detect BSE is 2-to-3 months before the animal begins to show symptoms. The time between initial infection and the appearance of symptoms is about 5 years. Since most cattle that go to slaughter in the United States are both young and clinically normal, testing all slaughter cattle for BSE might offer misleading assurances of safety to the public.

The BSE surveillance program is not for the purposes of determining food safety. Rather, it is an animal health surveillance program. USDA’s BSE surveillance program allows USDA to detect the disease if it exists at very low levels in the U.S. cattle population and provides assurances to consumers and our international trading partners that the interlocking system of safeguards in place to prevent BSE are working.

The safety of the U.S. food supply from BSE is assured by the removal of specified risk materials – those tissues known to be infective in an affected animal – from all human food. These requirements have been in place since 2004.

ONGOING BSE SURVEILLANCE PROGRAM SUMMARY

USDA’s BSE surveillance program samples approximately 25,000 animals each year and targets cattle populations where the disease is most likely to be found. The statistically valid surveillance level of 25,000 is consistent with science-based internationally accepted standards. This level allows USDA to detect BSE at the very low level of less than 1 case per million adult cattle, assess any change in the BSE status of U.S. cattle, and identify any rise in BSE prevalence in this country.

The targeted population for ongoing surveillance focuses on cattle exhibiting signs of central nervous disorders or any other signs that may be associated with BSE, including emaciation or injury, and dead cattle, as well as nonambulatory animals. Samples from the targeted population are taken at farms, veterinary diagnostic laboratories, public health laboratories, slaughter facilities, veterinary clinics, and livestock markets.

USDA’s National Veterinary Services Laboratories (NVSL) in Ames, IA, along with contracted veterinary diagnostic laboratories, will continue to use rapid screening tests as the initial screening method on all samples. Any inconclusive samples will be sent to NVSL for further testing and analysis. USDA’s surveillance program uses OIE’s weighted surveillance points system, which was adopted in May 2005 and reflects international scientific consensus that the best BSE surveillance programs focus on obtaining quality samples from targeted subpopulations rather than looking at the entire adult cattle population.

The number of points a sample receives correlates directly to an animal’s clinical presentation at the time of sampling. The highest point values are assigned to those samples from animals with classic clinical signs of the disease. The lowest point values correspond to clinically normal animals tested at routine slaughter.

The goal of this weighted approach is to ensure that countries sample those cattle populations where the disease is most likely to be found. This system is not different from USDA’s previous BSE surveillance approach, it is simply a different method for evaluating surveillance programs. Both approaches target those cattle populations where BSE is most likely to be found. The OIE is simply assigning point values to different categories of animals.

USDA has been targeting these subpopulations since BSE surveillance was initiated in 1990, and will continue to do so under the OIE weighted approach. Under the OIE guidelines, points compiled over a period of 7 consecutive years are used as evidence of adequate surveillance. At the current ongoing level of surveillance, the United States will far exceed OIE guidelines under the point system.

90,000 Mad cow disease as a factor in the development of dementia in humans

Victoria Doronina

In the midst of the coronavirus pandemic, Europeans will scold the Chinese more than once or twice: they say, if they did not eat any exotic, then a dangerous virus would not have jumped to us from bats. And then they will say: we Europeans are not like that. The British could claim the right to be considered the highest civilization in the world, if not for one thing. Do you know why the citizens of Foggy Albion who were born and lived in the UK before 1996 cannot donate blood in Europe?

As you know, Britain is the birthplace of capitalism.First, the inhabitants of the kingdom began to build steam engines, then they began to weave clothes with machines. The speed of production has increased, the cost of the product has dropped. In the same spirit, the remnants of agriculture in the second half of the twentieth century were transferred to an industrial basis: maximum income, minimum unproductive waste.

These included the bones of cattle. They guessed to clean off the remnants of meat and extract the bone marrow from them. All this to grind and sell as “mechanically deboned meat”. Dry the bones themselves and grind them into bone meal, which was fed to the same cows, and also added to pet food.

In the same mines, of which the first were, while stationary steam engines pumped out water, canaries were used to determine methane, an odorless and colorless gas. The canaries were the first to die, allowing the miners to escape. At the end of the 20th century, cats began to play the role of canaries. And first one cat, then the second died from an incomprehensible disease – at first they walked with braided legs, whirled in place and finally died.

A similar disease of the nervous system – sheep pruritus (when the sheep began to comb their sides until they bleed) – has been known in these paired mammals since the middle of the 18th century, but in the 1990s it was first discovered in cats.Since it was known that sheep pruritus was not transmitted to humans, the UK Department of Agriculture recommended not to pay attention to it, and British beef was considered completely safe.

Although by the end of the 1990s, Margaret Thatcher was no longer prime minister, in our story we cannot do without mentioning her name. The fact is that after World War II, Britain passed the School Meals Act, which stated that school meals should contain 50% of the calories children need.In the 70s, it was already 30%, and then Thatcher completely removed this minimum. During her reign, the state allocated less and less money for school meals (free for the poorest children). And now we already know where the bone meal of sick cows went and who regularly ate “mechanically deboned meat” – children.

The first cases of “mad cow disease” in humans were recorded in 1996 [1]. Symptoms included depression, anxiety, and hallucinations. Symptoms rapidly progressed to problems with coordination of movements and speech.Then came dementia, seizures and death. On average, the illness lasted 14 months, the average age of the cases was 28 years.

Note that a similar disease in humans – Creutzfeldt-Jakob disease – was observed before. It is known to affect people over the age of 50 and is genetic. Another similar disease, kuru, was found in the natives of New Guinea, who had a custom of eating the brains of deceased relatives. So, no one denied the spontaneous nature of Creutzfeldt-Jakob disease, but what is the mechanism of its transmission?

Researcher kuru Stanley B.Prusiner, American professor of neuroscience and biochemistry, 1997 Nobel laureate) suggested that the disease is transmitted without the participation of nucleic acids, only through protein. They did not believe him for a long time, because the “central dogma of molecular biology” Francis Crick said that information can be transmitted to proteins only from nucleic acids (DNA and RNA). In this case, after years of debate, “dogma” has been modified into the formula “protein -> protein”.

A cow’s brain under a microscope. White spots are visible, formed at the site of tissue destroyed by the accumulation of prions.Image: Dr. Al Jenny —Public Health Image Library, APHIS. aphis.usda.gov

Sheep pruritus, “mad cow disease” and kuru are prion diseases (recall that “a prion is a protein with an abnormal tertiary structure, capable of catalyzing the conformational transformation of a homologous normal cellular protein into a similar one”). In these cases, one protein, the PrPSc nervous system receptor, changes from its normal, soluble form to an irregular (prion) that folds into long filaments.

Filaments are not capable of performing the function of a protein, but they lead to the development of symptoms of the disease. Moreover, pieces are torn from the filaments that can convert normal protein into abnormal one. Mad cow disease, which crossed the species barrier, showed that prion infestation was possible.

As usual, after the first cases of the disease appeared, its development was projected into infinity, but since 2005 there has been a clear trend towards a fall in the number of cases, of which there were never too many – dozens.

Since then, Britain, taught by bitter experience, has abandoned the use of bone meal and “mechanically deboned meat”. It would seem that you can sleep peacefully. But there are still three problems left: a small one, a bigger one, and a very big one.

The little thing is that at the critical point of the PrP protein there are two variants of the amino acid – valine and methionine. All patients with mad cow disease had a valine / methionine combination. The natives have a different combination of amino acids, and it took them 50 years to develop the disease.It is not known how many people, former children who received those same school lunches and bought uncooked burgers at McDonald’s, will get sick with mad cow disease in old age. But it is unlikely that this surge will be noticeable against the background of the tsunami of dementia [2].

A bigger problem is caused by the fact that prion is transmitted not only through meat, but also through blood cells [3]. That is why the British are forbidden to donate blood in Europe, there are restrictions in Britain itself. Cannibalism among the British has not been noticed, but since people with an as yet undiagnosed disease donated blood, it could potentially appear in anyone who received a blood transfusion in Britain in the 1980s and 1990s.Studies of the removed appendix have shown that one in 2,000 Britons has accumulations of the prion form of PrP in their organisms [4].

And the biggest problem found in the mad cow study is that because prions do not contain nucleic acid, they are not killed by conventional surgical sterilization methods, “surviving” autoclaving. It is not known how many people carry latent prion infections and how many of them transmitted it in the hospital.

Finally, there is emerging evidence that neurodegenerative diseases such as Alzheimer’s and Parkinson’s, which exhibit prion-like protein aggregates, are also contagious [5].

Now, if you are offered to try something exotic – for example, squirrel brains, you better refuse, you already know that prions cross species barriers. In the United States, several cases of prion infection have been reported after eating protein brains [6]. However, elk meat is also not worth eating, since a particularly infectious type of prion is walking among North American elk and deer, which is transmitted to them through saliva [7].

It turns out that when it comes to safe food, the British turned out to be no better than the Chinese, although they were not let down by tradition, but, on the contrary, by technological progress.And, alas, no one can guarantee that new diseases associated with a person’s desire to expand his menu with our smaller brethren will not appear in Russia either.

Victoria Doronina , Assistant, Department of Science, Faculty of Education,
Manchester Metropolitan University (UK)

ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Creutzfeldt-Jakob-Disease-Fact-Sheet;
Abigail B Diack, Mark W Head, Sandra McCutcheon, Aileen Boyle, Richard Knight, et.al .. (2014). Variant CJD. Prion. 8, 286-295;
Alexander H Peden, Mark W Head, L Ritchie Diane, E Bell Jeanne, W Ironside James. (2004). Preclinical vCJD after blood transfusion in a PRNP codon 129 heterozygous patient. The Lancet. 364, 527-529;
Abigail B. Diack, Robert G. Will, Jean C. Manson. (2017). Public health risks from subclinical variant CJD. PLoS Pathog. 13, e1006642;
Alison Abbott. (2016) The red-hot debate about transmissible Alzheimer’s.Nature. News feature.
Joseph R Berger, Erick Weisman, Beverly Weisman (1997) Creutzfeldt-Jakob Disease and eating squirrel brains. The Lancet. 350, 907, 9078, P642
Richard F. Marsh, Anthony E. Kincaid, Richard A. Bessen, Jason C. Bartz (2016) Interspecies Transmission of Chronic Wasting Disease Prions to Squirrel Monkeys (Saimiri sciureus). Journal of Virology 79 (21) 13794-13796

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Mad cow disease and prion diseases

Prion diseases are a group of neurodegenerative diseases of humans and animals, etiologically associated with a special infectious protein – prion. These diseases are characterized by a severe progressive course and inevitable death.

GU Scientific Center of Neurology, Russian Academy of Medical Sciences

I.A. Zavalishin, I.E. Kaleonova

About 20 years ago, interest in prion diseases in the world sharply increased in connection with the registration of a new, especially severe and early variant of Creutzfeldt-Jakob disease, which appeared during the epidemic of the so-called bovine spongiform encephalopathy in England. The maximum morbidity in animals – up to 37 thousand heads – fell on 1992. In total, over the period from 1985 to 1996, 170 thousand head of livestock were affected. In addition, in addition to cows, spongiform encephalopathy was reported in five species of London Zoo antelopes, domestic cats, other animals and cows outside Britain during the same period.

In the spring of 1996, the registration of a new variant of the previously known but extremely rare Creutzfeldt-Jakob disease (the incidence in the world is 1 case per 1 million people per year) and the associated “mad cow disease” literally shook the economic and political circles of England. This variant of the disease appeared in 1995, with individual cases reported in France and Italy. The disease made its debut at a young age, which is atypical for this disease, known since the 1920s, and in the process of morphological examination of the brain of deceased patients, changes were revealed similar to those in bovine spongiform encephalopathy.

And now a little history …

For the first time, the term “spongy (spongy, spongy) encephalopathy” was used in 1957 by the Icelandic scientist B. Sigurdsson when describing diseases of sheep on the island of Iceland, which differed from all known diseases by four features: an unusually long (up to several years) incubation period; slowly progressing (months and years) nature of the course; unusual damage to organs and tissues; inevitable death.B. Sigurdsson combined such diseases under the general name “slow infections”.

Three years later, kuru was described for the first time – a previously unknown disease that occurs among savages with habits of ritual cannibalism on the island of New Guinea, manifested by impaired coordination of movements and tremors. The clinical and pathological symptoms of kuru in humans were similar to those in sheep’s disease, known since 1700 – scrapie. In 1966, Gaidushek proved the infectious nature of kuru on monkeys (chimpanzees).In 1967, researchers published data according to which the following were found in the brain of chimpanzee chimpanzees infected with the kuru virus: “sponginess” of the gray matter of the brain, an increase in the number of auxiliary cells (astroglia), the death of neurons in several parts of the brain. These morphological signs (with certain variations) are characteristic of all prion diseases of humans and animals.

Subsequently, spongiform encephalopathy was discovered in people suffering from Creutzfeldt-Jakob disease, Gerstmann-Streussler syndrome, and fatal familial insomnia.At the end of the last century, WHO experts predicted the possibility of a significant epidemic of a new variant of Creutzfeldt-Jakob disease in the next 10 years. But in the last 5 years, fortunately, there has been a clear tendency towards a decrease in the increase in the disease.

By 2005, however, about 140 cases of the new variant of Creutzfeldt-Jakob disease had been reported in England, France and Italy. The disease is characterized by an earlier than usual onset. The age of the patients varied from 16 to 40 years, at the onset of the disease, mental disorders in the form of anxiety, depression, changes in behavior were noted as clinical manifestations; after weeks and months, neurological disorders joined.In the later stages, as in other prion diseases, memory impairment, dementia, muscle twitching, increased muscle tone; the disease ends in death within 0.5-2 years. In Russia, there is no data on the appearance of a new variant of Creutzfeld-Jakob disease, although the usual Creutzfeld-Jakob disease with late onset of symptoms occurs with the same frequency as in other countries.

A big mystery and, accordingly, of interest is the fact that some variants of prion diseases can be infectious (for example, caused by a dura mater transplant or the use of tissue extracts containing growth hormone and gonadotropin), others are hereditary, and still others cannot are not associated with either heredity or infectious transmission.

In all cases, the culprit of the disease is its own defective protein – prion protein, which turns into an infectious analogue – prion. The prion, as it were, “forces” the surrounding normal prion protein molecules to take a pathological form, and this process has the character of a chain reaction. As Professor Stanley Prusiner aptly put it, “Dr. Jekyll is turning into Mr. Hyde.” A defective prion protein has abnormal properties and is contagious and fatal to any nearby neurons.

Professor S. Pruziner received the 1997 Nobel Prize in Physiology or Medicine for his proof of the existence of a new biological infectious agent – a prion that does not contain DNA or RNA, capable of carrying information and crossing the species barrier.

At present, the diagnostic criteria for prion diseases have been unified, and work is underway to identify and study them. The advances in molecular biology in recent years give hope for a deeper understanding of the cause of the disease and the mechanisms of pathological transformation of the prion protein and, most importantly, for finding effective means for the treatment of these deadly diseases.The preliminary results of experimental studies on cell cultures are very encouraging, and it is possible that some “anti-prion” compounds may become the object of the first clinical trials in the next 5 years.

Added on April 22, 2015

Mad cow disease spreads to cyborgs | Articles

This begs a great plot for a science fiction film.Scientists have used proteins that are destructive for humans to produce the latest microchips, and suddenly, after a few years, the creatures equipped with these mini-devices “get sick” and get out of control – a revolt of machines begins, a general madness of “terminators”.

The reason for such a plot is real. American researchers presented the results of work on a project to create microscopic blocks for ultra-miniature devices: destructive proteins – prions, infectious agents that “live” in the brain and bone marrow of animals and humans and cause neurodegenerative diseases (mad cow disease, Jacob).The term “prion” was coined by the American Stanley Prusiner, who received the 1997 Nobel Prize in Physiology or Medicine. He first suggested that mad cow disease and other types of spongiform encephalopathy are caused by a protein molecule that coagulates in an unusual way.

Most proteins maintain only one form throughout their life. Prions are common proteins found on the surface of nerve cells. In their normal state, their molecules are twisted in a certain way. For some reason, a prion molecule can suddenly change its shape, unwind and acquire a “wrong” configuration.Moreover, they affect other proteins of the same type, “infect” with this ability. Proteins in these expanded clusters cease their normal functions and either die or kill the cell and ultimately the body. In place of the dead nerve cell, a void is formed, filled with liquid. Gradually, microscopic pores form in the brain tissue, like holes in Swiss cheese. The diseased brain resembles a porous sponge, which is why the name of this group of diseases arose – spongiform encephalopathy.Structural properties of prions ensure their high stability and ability to self-replicate. Neuroscientists from Massachusetts’ Susan Lindqvist team recently found that they are able to self-fuse into ultra-thin and very strong threads. Prions, extracted from genetically modified yeast, formed fibers up to several millimeters long, with a diameter of about 100 nanometers (millionth of a millimeter). A human hair is about 100,000 nanometers thick.

The protein thread does not conduct electricity – it is covered with a thin layer of gold.When we tried to pass current through this conductor, it turned out that it has much less resistance than other microwires. It is impossible to obtain such “wires” by traditional methods, and their thickness is an order of magnitude less than with traditional microelectronic technologies.

It is not difficult to guess what will be the behavior of sick cyborgs in the film. The symptoms are known. Uneven gait, then complete paralysis of the legs. Animals lose weight and become restless, fearful – afraid of narrow passages, corridors and corrals.Cows are aggressive, gnash their teeth, try to separate from the herd, react sharply to light, sound, touch. A whole set of spectacular tricks with which you can play the “Mad Terminator”. Half-robots, half-humans will be pathologically aggressive and, most importantly, they will forget who they are working for. In humans, something similar happens – in addition to impaired coordination of movements and convulsions, patients experience complete loss of memory.

It turned out that prions are directly related to the properties of human memory.Recent research suggests what could be a memory storage device. It was quite surprising to find that prion-like activity plays a role here. And it may help explain one of the least understood functions of the brain. Kausik See of Columbia University found that a protein related to long-term memory preservation contained the hallmarks of a prion. Protein CPEB (cytoplasmic polyadenylation element binding protein), being in the state of a prion, exhibits useful qualities.It is found at synapses in the central nervous system – junctions that connect neurons in the brain. During training, new interneuronal connections are formed, the old ones are strengthened. CPEB synthesizes proteins that enhance these compounds, allowing memory to be retained for a longer period.

In the study, scientists extracted CPEB from a sea slug. This humble creature is highly regarded in neuroscience because its neurons are so large that they can be manipulated and used as a research tool.It was found that CPEB changed shape and forced other proteins to do the same – just like a prion. Second find: CPEB performed a normal protein synthesis function when it was in a prion state.

The results obtained indicate that prions are involved in fundamental processes. This finding contradicts the view that conversion to a prion state is unambiguously negative – it can be effective when using the protein’s normal function. It is possible that in mammalian neuronal synapses, the prion properties of CPEB may be a mechanism that allows the storage of long-term memory.In theory, prions are ideal for this. They can go into this state quickly and without high energy consumption. The state of the prion is very stable and can self-sustain for months, even years.

The researchers are confident that new and interesting results await them. 2000 Nobel Prize in Physiology or Medicine, Eric Kandel, said he would not be surprised if this kind of prion mechanism is found in areas such as cancer development and even organ formation. It turns out that the useful and the destructive are somewhat similar.As in drama – everything balances on a fine line between good and evil.

The small number of people affected by spongiform encephalopathy is little consolation. According to some scientists, hundreds of thousands of people in Europe are infected with it, but they do not even know about it. The incubation period for mad cow disease in humans can be 30 years. A vaccine against mad cow disease has not yet been developed. And therefore scientists fear that the next “plague of the century” will show itself. But this is a plot for another film. Of course, according to the law of the happy end, people will find a way to defeat the common infection.An enzyme has recently been discovered that degrades prion proteins. However, so far we are talking only about a successful experiment “in a test tube”. A group of American and Dutch scientists informed about this. The enzyme that degrades these proteins was keratinase isolated from the bacterium Bacillus licheniformis. One of the authors of the work, professor at the University of North Carolina Jason Sheeh, decided to test how keratinase affects the brain tissue of animals with prion diseases. It turned out that in the presence of a certain surfactant (detergent) prion degrades without a trace.Professor Shikh’s success in degrading disease-causing prions with bacterial keratinase has been achieved in vitro. A $ 190,000 project has already been launched to study the effects of keratinase on mad cow disease prions in a special strain of mice. And today we can only speak with confidence about the use of the destructive effect of keratinase on prions for the disinfection of medical and laboratory equipment.

Mad cow disease abstract on biology

But where did this attack come from? Indeed, before mad cow disease was exotic, Kreuzfeldt-Jacob disease was almost never encountered, and now in Great Britain alone 177 thousand cases of mad cow disease have been registered, 88 people have died from Kreuzfeldt-Jacob disease! Many people have the idea that we live in some kind of fixed world.In fact, we live in a world that is constantly changing. The evolution of viruses, the evolution of bacteria, the evolution of everything that can cause pathological conditions, is happening all the time. The AIDS virus is evolving, that is, its new forms and mutations are constantly appearing. The flu virus is evolving. And therefore, it is not surprising that what is happening now with the disease of rabies in cows is also a case of such evolution, but evolution not without human intervention. But this does not mean that there were some laboratories that created prions as weapons and then tried to use them – this is complete absurdity.What most likely happened is that people began to use animal products to feed the animals themselves, which is completely unnatural: as we all know, cows are herbivores. But in order for the cows to be more meaty and, accordingly, more commercially profitable, they began to feed them food that contains a lot of proteins. This food is made from the same cows or other animals. Thus, things began to get into food, which in the course of normal evolution never got into the food of cows.Most likely, sometime, at some stage, some of the cows – or some other animal – fell ill with the disease of rabies cows. It is clear that if there are diseases that are caused by prions, then they could arise among cows. But if this cow had not been used to make fodder out of it for another cow, and had not been fed to her, then the problem of the development of the disease would not have arisen, because – as in the case of the cannibals discovered by Gaydushek – In order to become infected with this disease, you need to eat a sick animal or a diseased organ of a sick animal.Which is exactly what happened. And rabies cow disease began to spread because cows were fed animal products, including those that were already infected with cow rabies disease. Where did the epidemic come from? Why did a rare disease suddenly take on the character of a cow epidemic? About eight years ago, scientists suggested that the main source of infection for cattle in England is meat and bone meal obtained from sheep carcasses (among which there were animals sick with scrapies) and added to feed.True, bone meal was added to the cow’s diet 50 years ago, and the mad cow disease epidemic broke out only recently. The thing is that 15 years ago in Great Britain the technology of processing sheep carcasses into bone meal was changed – some stages of high-temperature processing were omitted. As a result, the pathogen retained its activity and the cows massively fell ill with spongiform encephalopathy. Most likely, mad cow disease is transmitted through feed, and not directly from one animal to another.Therefore, in a herd, sometimes only one or two cows get sick. But there is a high probability that the disease is transmitted to the cow offspring – from parents to children. Any of the listed diseases can have three variants of occurrence: a) infectious (already mentioned), b) hereditary, c) sporadic, that is, the appearance, it would seem, for no apparent reason, when no hereditary predisposition or infection is visible. It turns out that there are very many. The fact is that in industrially developed Western Europe, so-called protein supplements are used for fattening livestock.One American veterinarian claimed that these additives are made from the meat of animals and birds that have died and died from diseases. Moreover, dead “pets” are processed together with anti-flea collars, spoiled meat from supermarkets – with plastic packaging. (Incidentally, this same mass is used to produce food for dogs and cats that is highly praised by advertising.) It turns out that cows are fed with a product that contains the meat of their relatives. A “prion riot” in the body of a cannibal cow leads to the emergence of spongiform encephalitis infection, which is dangerous for a person who follows the cow in the food chain.What most likely happened is that people began to use animal products to feed the animals themselves, which is completely unnatural: as we all know, cows are herbivores. But in order for the cows to be more meaty and, accordingly, more commercially profitable, they began to feed them food that contains a lot of proteins. This food is made from the same cows or other animals. Thus, things began to get into food, which in the course of normal evolution never got into the food of cows.Good and bad prions A little explanation is required here: protein molecules, which are known to be long chains of amino acid residues, also have a well-defined spatial organization. Therefore, when characterizing a protein, scientists talk about its primary, secondary, tertiary, and in some cases, quaternary structures. The primary structure of a protein reflects its amino acid sequence, that is, the order of alternation of amino acid residues in the molecule. The secondary structure of a protein reflects the conformation of the molecule, i.e.That is, the way it is twisted in space. One of the most common patterns is the spiral. The tertiary structure of a protein reflects the three-dimensional configuration of an already coiled molecule in space. Let’s say the same spiral, but also curved. Well, the quaternary structure of a protein is formed due to the interaction between different molecules and is characteristic only for some proteins, for example, hemoglobin. Each protein has its own constant unchanging structure, by which the cell identifies it. This is a kind of password, the key to the lock.Any protein with a structure unfamiliar to the cell is foreign to it and subject to inactivation. So what do prions do? Professor Tarakhovsky explains: Prions are able to convert a protein from the usual conformation to an unusual conformation, which is perceived by the cell as something foreign, and the cell tries to destroy this protein, turn it into something that cannot be used by the cell, and this protein becomes insoluble. That is, it turns into some kind of particles, and these particles form threads, or cords, which have practically no function – the one that these proteins performed.They just fill the cell space. That is, from the point of view of the cell, it fulfilled its function, because it inactivated the protein of the wrong conformation. But for the cell, this inactivation has monstrous consequences, because these non-functional proteins, accumulating in the cell, practically kill it. And many cells containing these proteins die. The horror is that these prions have the ability, by binding to proteins, to convert them into such a conformation, which then does not come back.Thus, this is an almost irreversible process. through enzymes. While PrPk prions are readily degraded, PrPsk prions exhibit extremely high resistance to enzymes, heat, and disinfectants. CHRONOLOGY OF THE EPIDEMIC prion proteins can exist in two different forms. Absolutely identical in composition, these two forms differ greatly in their spatial structure. If the protein is in its usual form, it dissolves well in biological fluids and is able to perform its proper function.Once in a different, abnormal, form, it forms insoluble aggregates and acts as a body that is alien and harmful to the body. It is with the relationship between these two properties that the most important property of prions is associated – a phenomenon that biologists have never encountered before. A squirrel that is in an abnormal form, colliding with its relative, which has a normal form, converts it into the same abnormal form. So, it turned out that the proteins discovered by Prusiner turn out to be causative agents of diseases: getting into a healthy body, an abnormal protein “infects” proteins that were previously in their usual form, as a result, aggregates accumulate that destroy brain cells.OPINION Following in the footsteps of Aesculapius (live on Radio Liberty) Daniil Golubev: According to him, the protein molecule of a normal prion has the shape of a spiral, it is as if folded (“twisted”). When, for one reason or another, the molecule “unwinds” and begins to resemble a bunch of smooth hair, prions become deadly. Contacting normal prions, pathogenic prions induce changes in the shape of their molecules, that is, transform them into pathogenic ones. There is a kind of molecular chain reaction of such changes, accompanied by degeneration of the nerve cells of the brain.The mechanism of transmission of infection Both the alpha and beta conformation of a prion is a helix, the only difference is that a molecule of a pathogenic protein has about 10 percent fewer bent areas than a protein molecule of a harmless one. By the way, prions are the smallest of all known infectious agents: they are about a hundred times smaller than viruses. The worst thing – and biologists have never met this phenomenon before – is that a pathogenic prion, colliding with its normal relative, transforms it into its conformation, that is, it infects, as it were.And once in another organism, a prion can cause the appearance of beta conformations of normal proteins encoded in the same gene as itself. This was the mechanism of transmission of the “kuru” infection during ritual cannibalism in New Guinea, as well as the infection with Kreuzfeldt-Jakob disease when eating the meat of prion-infected cows. The manifestation of this disease at one time was called softening of the brain. But this is a banal language that does not explain the pathology itself. And the pathology is such that the prions that cause rabies in cows, getting into the cells, lead to the emergence of these fibrils, or strands, and the cells are destroyed, degenerate.Thus, there is an irreversible loss of brain cells, over time, the symptoms of the disease become apparent, and the person dies. Where do the “wrong” prions come from? The cause of the disease (Creutzfeldt-Jakob, for example) may be a hereditary predisposition. A small error in the nucleotide sequence of the gene encoding the GO prion causes the synthesis of “incorrect” protein molecules with a “untwisted” configuration. Probably, such abnormal prions in humans and animals, in the presence of a genetic predisposition, accumulate with age and ultimately cause the complete destruction of brain neurons.It is believed that when at least one untwisted prion molecule enters the human or animal organism, gradually all other “normal” prions begin to unfold in a similar way. How an “abnormal” prion molecule unfolds a normal prion is unknown. Scientists are looking for a molecule – an intermediary in this chain of chemical reactions, but so far without success. – Prions are capable of converting a protein from an ordinary conformation to an unusual conformation, which is perceived by the cell as something foreign, and the cell tries to destroy this protein, turn it into something that cannot be used by the cell, and this protein becomes insoluble.That is, it turns into some kind of particles, and these particles form threads, or cords, which have practically no function – the one that these proteins performed. They just fill the cell space. That is, from the point of view of the cell, it fulfilled its function, because it inactivated the protein of the wrong conformation. But for the cell, this inactivation has monstrous consequences, because these non-functional proteins, accumulating in the cell, practically kill it. And many cells containing these proteins die.The horror is that these prions have the ability, by binding to proteins, to convert them into such a conformation, which then does not come back. Thus, this is an almost irreversible process. However, not all proteins in a row undergo such transformation, but only the same prions. The fact is that the gene encoding the primary structure of prions, that is, determining their characteristic amino acid sequence, has been found not only in all humans, but in general in all mammals and even in some birds.This means that in nature there are at least two forms of the corresponding protein – normal, always present in the body of humans and animals, and pathogenic, which, in fact, is called a prion. The term “prion” itself is an abbreviation of the phrase “infectious protein”, that is, “infectious protein”. Most of the prion proteins are in the brain, much less in the lungs, intestines, spleen, and even less in the muscles. As long as the prion protein is in its usual form – it is called the alpha – conformation – it dissolves well in biological fluids and is capable of performing its function, although scientists do not yet know which one.However, occasionally and for unknown reasons, this protein takes on a different, abnormal form – it is called beta – conformation – forms insoluble aggregates and acts as a foreign and harmful body to the body, ultimately destroying the work of the entire nervous system. The mechanism of transmission of infection Both the alpha and beta conformation of a prion is a helix, the only difference is that a molecule of a pathogenic protein has about 10 percent fewer bent areas than a protein molecule of a harmless one. By the way, prions are the smallest of all known infectious agents: they are about a hundred times smaller than viruses.The worst thing – and biologists have never met this phenomenon before – is that a pathogenic prion, colliding with its normal relative, transforms it into its conformation, that is, it infects, as it were. And once in another organism, a prion can cause the appearance of beta conformations of normal proteins encoded in the same gene as itself. This was the mechanism of transmission of the “kuru” infection during ritual cannibalism in New Guinea, as well as the infection with Kreuzfeldt-Jakob disease when eating the meat of prion-infected cows.- The manifestation of this disease at one time was called softening of the brain. But this is a banal language that does not explain the pathology itself. And the pathology is such that the prions that cause rabies in cows, getting into the cells, lead to the emergence of these fibrils, or strands, and the cells are destroyed, degenerate. Thus, there is an irreversible loss of brain cells, over time, the symptoms of the disease become apparent, and the person dies. During experiments on the infection of mice, which were injected directly into the brain material containing the pathogen, it was possible to transfer and cause the disease.When mice were used that were modified by genetic engineering and did not possess healthier PrPk, such experiments on infection did not succeed. O. a prerequisite for TSE with the help of PrPs is the presence of healthy PrPs. Obviously, infectious proteins, after contact in the brain, are capable of causing a chain reaction, during which harmless, healthy prions are transformed into their destructive “counterparts” PrPsk. At the present time, this can already be proved with the help of laboratory experiments in test tubes.In the course of these experiments, cell prions change their spatial structure as a result of contact with “scrapy – prions”. Unlike normal prions, disease-causing prions are not destroyed in the stomach. Perhaps the immune system plays an important role in their spread. The fact is that scientists have found in sheep, cows, as well as in humans, an increased concentration of prions not only in the brain, but also in the tonsils, intestines and spleen. The latest hypothesis is that prions accumulate and multiply in certain protective cells in the lymph nodes and spleen.However, it remains unclear how the prions then travel from the spleen to the brain. But as soon as they get there, they immediately begin their destructive activities. They convert normal prions into their infectious variant. The latter, in turn, is capable of causing the transformation of other cellular prions. Disease-causing prions do not lend themselves to degradation and accumulate in nerve cells as “garbage” or “waste”. Sooner or later, there comes a moment of overflow of the nerve cell, which, as a result, loses its ability to function normally and is gradually dying off.This process is at first imperceptible, “creeping” in nature. Only in the stage of progressive cell disintegration does the rate of its destruction increase. Finally, so many nerve cells die off that the brain acquires an easily recognizable typical spongy structure. At the same time, the changes occurring cause the above symptoms. According to the “prion theory” created by Pruziner, infectious proteins (light gray, PrPsk) are capable of causing a chain reaction in the brain. Harmless, healthy prions (dark gray, PrPk) turn into their destructive “counterparts”.Prions cause incurable neurodegenerative brain diseases in animals and humans. One of them – spongiform encephalopathy – today is literally on everyone’s lips, since the animal form of this disease, commonly referred to as “mad cow disease”, is becoming more and more widespread in Europe, and meanwhile it can be transmitted to people, causing the so-called Creutzfeldt-Jakob disease. Degenerative diseases, in which the brain is destroyed, turning into a kind of sponge, have been known for a long time.In sick animals, vacuoles – microscopic pores – are visible on a section of the brain under a microscope. The diseased brain resembles a porous sponge, hence the scientific name of this group of diseases – spongiform encephalopathy. Spongiform encephalopathy affects cows, sheep (the so-called scrapie disease), goats, rodents and even cats. The animal dies from complete brain destruction. Similar diseases, although extremely rare, are found in humans: Kuru disease (common among the Papuans of New Guinea) and Creutzfeldt-Jakob disease.The latter has been known since the last century, and it strikes approximately one out of a million criteria. In the case of processing infected tissue samples using methods that kill viruses and bacteria, absolutely nothing happened. Neither alcohol-based disinfectants nor ultraviolet radiation destroyed this “unconventional” pathogen. In the end, it was possible to end it only by treating the samples with concentrated acids and chlorine-containing solutions. Further history remained as before exciting.In 1972, one of the patients of the American doctor Stanley Prusiner died of TSE. Pruziner wanted to understand the cause of his death and read many books for this purpose. In his search, he came across the works of Charles Gaidusek and Vincent Tsigas. The latter in 1967 described a disease that broke out in the archipelago of Papua New Guinea among members of the indigenous Fore tribe. The natives themselves called this disease “kuru” (“laughing death”). The fact is that people who fell ill with it at first were seized by bouts of involuntary laughter, after which symptoms similar to those of TSE were added to them.The most surprising thing, however, was the parallels between kuru, TSE, and sheep’s “trotting sickness.” Gaidusek and Tsigas concluded that the cause of the infection should be sought in cannibalistic rituals, during which the tribe devoured the brains of the dead. Impressed by this conclusion, Pruziner, as a result of many years of his own research work, developed a hypothesis according to which the causative agent of “trotting disease” is devoid of a hereditary substance. According to his assumptions, this pathogen was a certain protein.He gave it the name “Proteinous infectious particle” (translated: “infectious protein-like particles”), abbreviated: prion – protein (PrP). Unlike bacteria or viruses, an infectious prion does not “live”, since it does not contain any nucleic acids or any hereditary information. Obviously, such a prion, despite the lack of hereditary information, has the ability to reproduce and can be transferred. Thus, he turns all the laws of microbiology and toxicology “upside down”.In 1982, Prusiner published his theory in the specialized journal Science (USA). At first, he faced opposition from specialists. However, over time, this “prion hypothesis”, after many years of unsuccessful searches for the virus, has become increasingly recognized. The crowning achievement of this success was the award of the Nobel Prize in Medicine to Pruziner in 1997. The Kuru, or “laughing death”, was discovered in New Guinea in the Fore tribe by Daniel Carlton Gaidushek (Gaiduzek) in the mid-1950s.Symptoms – progressive impairment of coordination of movements, accompanied by bouts of unreasonable laughter and resulting in death. The disease was recognized as infectious, and the reason for its spread was ritual cannibalism in the Fore tribe. It should be noted that Creutzfeldt-Jakob disease was described by Jacob much earlier, in 1921. As it was found much later (in 1981 – Pat Merz, and in 1982 – Stanley Prusiner), for mice infected with scrapie, a characteristic feature of the head and the spinal cord of sick animals is the presence of protein cords, which are aggregates of one of the proteins of the nervous system, the function of which has not yet been completely established.In addition, the spinal cord and brain of sick people and animals resembles a sponge, hence the common name of this group of diseases – spongy brain diseases. Recall that the life expectancy of a sick person is about 9 months and almost always the disease ends in death. This varioid, which occupies an intermediate position between living and inanimate matter, turned out to be 100 times smaller than the smallest virus. Therefore, when buying meat, you need to carefully consider it.Meat with rich yellow to orange fat is most likely infected. Prion proteins withstand boiling for two hours. Fans of “bloody dishes” in order to avoid infection, it is better to refuse them. Pavel MOTAVKIN, professor, specially for “V” 02.19.99 “Vladivostok – news” NEWS FROM LABORATORY Another step towards solving the mystery of the prion is also known Its ability to change its shape is also known. Only a deformed prion is “contagious”; it is able to “induce” a neighboring healthy prion to change its shape.Cows with mad cow disease have so many deformed prions that they paralyze brain function. In this case, we are not talking about a chemical change in a healthy prion, but only about a change in its external form. (ITAR – TASS, 13.01.2000) NBP ‘Alliance – Media PRIONS OF YEAST AND THE CENTRAL DOGMA OF MOLECULAR BIOLOGY SG Inge – Vechtomov Inge – Vechtomov Sergei Georgievich – Corresponding Member of the Russian Academy of Sciences, Head of the Department of Genetics and Selection at Leningrad State University. This study was supported by the Russian Foundation for Basic Research (Grant No. 99 – 04 – 4960) The modern view of genetic information is captured in the table of the genetic code [1].In it, 61 out of 64 possible combinations of three bases of ribonucleic acid correspond to 20 amino acids from which proteins are built. The three remaining combinations (UAA, UAG, UGA) are a kind of stop signals, or signals to stop the growth of a protein molecule. This code is quasi-universal, that is, it is valid (with minor modifications) for all living beings [2]. Of all these incurable fatal diseases of humans and animals, the most famous recently is the so-called mad cow disease, it is also a spongy disease of the brain of cows, or BSE (Bovine Spongiform Encephalopathy).PrPC PrPSc Similar diseases are known in a number of mammals, primarily in sheep and goats (as well as in mice, hamsters, cats, etc.) under the name scrapie, or prurigo. All of these diseases are caused by an infectious prion protein denoted as PrPSc (from Scrapi). This protein has a normal cellular homologue, that is, a non-disease-causing and non-infectious protein, designated as PrPC (from Cellular, that is, cellular) [8]. The word prion originated as a modified abbreviation of English: Protenacious Infection – protein infection.A characteristic manifestation of all these diseases at the last stages of their development is the formation of myeloid cords and plaques in the tissues of the brain and spinal cord, consisting of the aforementioned prion protein PrPSc. In this case, the brain tissue on the cut takes the form of a sponge. Hence the name “spongy brain disease”. REFERENCES 1. Crick F. H. C. The genetic code – yesterday, today, and tomorrow // Cold Spring Harbor Symp. Quant. Biol. 1966. V. 31. P. 3 – 9. 2. Osava S., Jukes T. N., Watanabe K., Muto A. Recent evidence for evolution of the genetic code // Microbiol.Rev. 1992. V. 56. P. 229 – 264. 3. Ayala F., Keiger J. Modern genetics. T. 2. M .: Mir, 1988. S. 34 – 66. 4. Sanger F. The structure of insulin // Currents in Biochemical Research. Wiley Interscience. N. Y., 1956. 5. Sanger F. Nobel Prize winners. T. 2.M .: Progress, 1992. S. 379 – 383. 7. Prusiner S. B. Prions // Proc. Natl. Acad. Sci. USA. 1998. V. 95. P. 13363-13383. 8. Prusiner S. B. Molecular biology and pathogenesis of prion diseases // TIBS. 1996.21 December. P. 482 – 487.15 Bessen R.A., Marsh R. F. Distinct PrP proteins suggest the molecular basis of strain variation in transmissible mink encephalopathy // J. Virol. 1994. V. 68. P. 7859 – 7868. 16. Aguzzi A., Weissmann C. A suspicious signature // Nature. 1996. V. 383. P. 666 – 667. 17. Parchi P., Capellari S., Chen SG, Petersen RB, Gambetti P., Kopp N., Brown P., Kitamoto T., Tateishi J., Giese A ., Kretzschmar H. (with reply by: Collinge J., Hill AF, Sidle KCL, Ironside J.). Typing prion ISO – forms // Nature. 1997.V. 386. P. 233-234. 18. Prusiner S. B., Scott M. R. Genetics of prions // Ann. Rev. Genet. 1997. V. 31. P. 139 – 175. VIVOS VOCO May 2000 The most interesting thing is that human and cow prions are very similar, so the meat of cows infected with spongiform encephalitis is deadly. which American Stanley Prusiner received the 1997 Nobel Prize. Prions cause incurable neurodegenerative brain diseases in animals and humans. One of them – spongiform encephalopathy – today is literally on everyone’s lips, since the animal form of this disease, commonly referred to as “mad cow disease”, is becoming more widespread in Europe, and meanwhile it can be transmitted to people, causing the so-called Creutzfeldt-Jakob disease.This disease, first described in 1920, for a long time remained an extremely rare phenomenon, one might say, exotic. Now experts do not exclude the possibility of an epidemic no less terrible than the AIDS epidemic in Europe. “Slow viruses” and their features – Structures were found that have not yet been fully characterized, but are so impressive that a Nobel Prize was awarded for their characterization. These structures are called prions. Prions are not nucleic acids, that is, not DNA or RNA, they are not something that is usually carried by viruses or bacteria and causes diseases, and prions are proteins, as it were, frozen in a certain state.Until recently, many scientists argued that two-thirds of humanity is generally resistant to bovine prions and that susceptibility to them is characteristic only of people with quite specific features of the gene structure. However, now, it seems, we have to admit that hereditary factors determine, first of all, the duration of the incubation period of the disease. In other words, many researchers today are already inclined to believe that a person who has tasted beef contaminated with prions is still doomed to get sick – the only question is when this will happen.A sensation was the news that quite recently a certain aborigine of New Guinea died of the disease “kuru”, who last ate a human brain in 1956. It was proved that later he could not get infected, which means that the incubation period in this case was 44 years! Vladimir Fradkin, Science and Technology magazine on the German Wave. DISCOVERY OF A NEW TYPE OF EXCITANTS – PRION. SCIENTIFIC BACKGROUND. Of all these incurable fatal diseases of humans and animals, the most famous recently is the so-called mad cow disease, it is also a spongy disease of the brain of cows, or BSE (Bovine Spongiform Encephalopathy).