New blood tests can detect prions

Tine Hesman Saey of Science News reports a new blood test can detect even tiny amounts of infectious proteins called prions, two new studies show.

prion-test-dec-16Incurable prion diseases, such as mad cow disease (BSE) in cattle and variant Creutzfeldt-Jakob disease (vCJD) in people, result from a normal brain protein called PrP twisting into a disease-causing “prion” shape that kills nerve cells in the brain. As many as 30,000 people in the United Kingdom may be carriers of prions that cause vCJD, presumably picked up by eating BSE-tainted beef. Health officials worry infected people could unwittingly pass prions to others through blood transfusions. Four such cases have already been recorded. But until now, there has been no way to screen blood for the infectious proteins.

In the test, described December 21 in Science Translational Medicine, magnetic nanobeads coated with plasminogen — a protein that prions grab onto — trap prions. Washing the beads gets rid of the rest of the substances in the blood. Researchers then add normal PrP to the beads. If any prions are stuck to the beads, the infectious proteins will convert PrP to the prion form, which will also stick to the beads. After many rounds, the researchers could amplify the signal enough to detect vCJD prions in all the people in the studies known to have the disease.

No healthy people or people with other degenerative brain diseases (including Alzheimer’s and Parkinson’s) in either study had evidence of the infectious proteins in their blood. And only one of 83 people with a sporadic form of Creutzfeld-Jakob disease tested positive. Those results indicate that the test is specific to the vCJD prion form, so a different test is needed to detect the sporadic disease. 

In two cases, researchers detected prions in frozen blood samples collected 31 months and 16 months before people developed vCJD symptoms.

Low incidence of TSEs in the EU, says EFSA

EFSA has published its first EU summary report on the monitoring of Transmissible Spongiform Encephalopathies (TSEs) in cattle, sheep and goats. Previously, the annual reports on TSEs were compiled by the European Commission.

TSEs are a group of diseases that affect the brain and nervous system of humans and animals.  With the exception of Classical BSE, there is no scientific evidence that other TSEs can be transmitted to humans.

mad-cows-mothers-milkA low number of BSE cases in cattle were detected in EU Member States, none of which entered the food chain.

Some of the main findings of the report are:

Five cases of BSE in cattle have been reported in the EU, out of about 1.4 million animals tested.

641 cases of scrapie in sheep (out of 319,638 tested) and 1,052 in goats have been reported (out of 135,857 tested) in the EU.

This report provides results on data collected by all EU Member States, Iceland, Norway and Switzerland for 2015 on the occurrence of bovine spongiform encephalopathy

Beneficial role clarified for brain protein associated with BSE

Studying mice and zebrafish, researchers from Washington University School of Medicine in St. Louis and the University of Zurich have shown that the proteins — when properly folded — play a vital role in nerve cell function by maintaining the insulation around axons, the nervous system’s electrical “wiring.”

prionThe study appears August 8 in the journal Nature.

Improperly formed prion proteins that cause disease are infectious because they hijack their neighbors, resulting in misfolded proteins and setting off a domino effect that spreads through the brain destroying tissue. Although the role of prion proteins in these fatal brain diseases is well-known, scientists have long puzzled over the normal function of the protein, called PrPC.

“Previous studies have suggested a role for prion proteins in maintaining neurons, but until now, no one knew how the properly folded versions of the proteins function,” said co-author Kelly R. Monk, PhD, an associate professor of developmental biology at Washington University. “It’s surprising to see that the protein has a role in maintaining the structure of nerve cells, considering that a misfolded version of PrPC is known to cause fatal brain diseases.”

Past work by the researchers at the University of Zurich demonstrated that mice lacking PrPC had disruptions in the insulation surrounding axons, but the reasons for the disruptions were unclear. The new study demonstrates that PrPC binds to Schwann cells, which are cells that provide support for the brain’s neurons. Schwann cells produce the nerve-insulating protein called myelin and then wrap this insulation around the long, thin axons. Properly insulated axons enable the rapid propagation of nerve signals. Specifically, PrPC binds to a docking site on Schwann cells called Gpr126.

In past work, Monk and her Washington University colleagues demonstrated that the docking site on cells played an important role in nerve formation during embryonic development in zebrafish and in mice. But the new study identifies roles for both Gpr126 and PrPC in maintaining the integrity of neurons through adulthood.

When either of these components is missing, Monk said mice experience a gradual loss of interactions between Schwann cells and axons, with a resulting loss of of myelin. Without this important insulation, walking progressively becomes more difficult for mice, and they eventually reach a state of paralysis.

“We have identified a definitive function for the normal prion protein and clarified how it works on a molecular level,” said senior author Adriano Aguzzi, MD, PhD, of the University of Zurich. “Our study answers a question that has been intensely researched since the prion gene’s discovery in 1985.”

The researchers said the findings may have implications for understanding and eventually treating nerve disorders that result from the loss of the insulating myelin sheaths, such as Charcot-Marie-Tooth disease and other devastating peripheral neuropathies.

‘Veal calves that regain the ability to walk after being warmed or rested may enter the food supply’ No more

The U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) announced changes today to improve humane handling inspections at facilities that produce veal meat.

265x184_veal_calfWith this change, FSIS will begin to require that veal calves that are brought to slaughter but cannot rise and walk be promptly and humanely euthanized, and prohibited from entering the food supply. Previously, FSIS has allowed veal calves that are unable to rise from a recumbent position to be set aside and warmed or rested, and presented for slaughter if they regain the ability to walk. FSIS has found that this practice may contribute to the inhumane treatment of the veal calves. This change would improve compliance with the Humane Methods of Slaughter Act by encouraging improved treatment of veal calves, as well as improve inspection efficiency by allowing FSIS inspection program personnel to devote more time to activities related to food safety.

Additionally, after review and consideration of comments to the proposed rule, FSIS is amending the regulations by removing a provision that requires ante-mortem inspection to be conducted in pens. This final rule makes clear that FSIS inspectors have the authority to conduct ante-mortem inspection and condemn non-ambulatory disabled veal calves the moment they arrive on the premises of the establishment.

“FSIS is dedicated to ensuring that veal calves presented for slaughter at FSIS-inspected facilities are treated humanely,” said Deputy Under Secretary Al Almanza. “Prohibiting the slaughter of all non-ambulatory veal calves will continue this commitment and improve compliance with the Humane Methods of Slaughter Act.”   

Since 2004, FSIS has prohibited the slaughter of non-ambulatory cattle for human food because the inability to rise may be a symptom of Bovine Spongiform Encephalopathy (BSE). While BSE is not a serious risk in cattle younger than 30 months of age, the regulations apply to all cattle, including veal calves. Currently, unlike adult cattle, veal calves that regain the ability to walk after being warmed or rested may enter the food supply. In 2013, FSIS granted a petition by the Humane Society of the United States asking the agency to remove this provision. This new rule will remove the provision, requiring that non-ambulatory calves be promptly and humanely euthanized, in keeping with requirements for adult cattle.

The final rule will be effective 60 days after publication in the Federal Register. A draft copy of the final rule is available here:http://www.fsis.usda.gov/wps/portal/fsis/topics/regulations/federal-register/interim-and-final-rules.

 

News amplification: Mad cow disease far greater impact on beef purchases than E. coli

In December 2003, Bovine Spongiform Encephalopathy (BSE) was discovered in the United States. This food safety event received extensive media coverage and prompted changes in regulatory controls.

bse.cow.may.16Using a panel selection model, we show that prior to December 2003, ground beef recalls had no impact on household purchases of ground beef, even for households that were located in the recall-defined geographic areas. However, we find robust evidence that the 2003 BSE event caused a change in the way people view and respond to recalls of ground beef, a change that persisted for at least two years following the BSE event.

The average impact of a ground beef recall in the post-BSE period is a 0.26 lb per person reduction in retail purchases of ground beef. A decline in purchases of this magnitude would result in over $97 million in losses to the beef industry in a two-week period following a nationwide recall.

This dwarfs the economic impacts of directly removing recalled beef from supply chains and provides FSIS increased regulatory power due to higher overall industry costs associated with food safety violations.

Changes in U.S. consumer response to food safety recalls in shadow of a BSE scare

Mykel Taylora, H. Allen Klaiberb, Fred Kuchlerc

Food Policy, Volume 62, July 2016, Pages 56-64, doi:10.1016/j.foodpol.2016.04.005

http://www.sciencedirect.com/science/article/pii/S0306919216300239

Why is contaminated feed still circulating, 15 years later? CFIA says small amount of feed likely cause of Alberta mad cow disease

Canada’s food safety watchdog says a small amount of leftover contaminated feed was the most plausible cause of mad cow disease discovered last February on a farm near Edmonton.

bse.canadaThe Canadian Food Inspection Agency released a report Monday that says no part of the Black Angus beef cow entered the human food or animal feed systems.

The report says no significant events could be linked to the discovery of bovine spongiform encephalopathy (BSE) near Edmonton and no other sick animals were found.

The February case — the 19th in Canada — prompted a few countries to place temporary restrictions on Canadian beef imports.

An investigation report says the cow was born at a nearby farm almost two years after Canada brought in more strict controls on animal feed to prevent BSE. A previous case was diagnosed on the same birth farm in an animal born in 2004.

“No significant events could be linked with this case but the potential for the carry-over of a small amount of residual contaminated feed could not be discounted,” says the report.

Oh Canada: Finding source of BSE ‘a needle in a haystack’

Canadian Agriculture Minister Gerry-what-Listeria-Ritz says figuring out how an Alberta cow was infected with BSE is like looking for a needle in a haystack.

ITALY-G8-G5-AGRICULTURE-FARMThe beef breeding cow was discovered last month on a farm near Edmonton and was born on a nearby farm.

Another cow born on the same farm in 2004 tested positive for bovine spongiform encephalopathy in 2010.

He says the feed system is also being checked to see if there’s any kind of “smoking gun.”

Ritz says a number of countries that have temporarily suspended imports of Canadian beef are being kept in the loop, but he points out they only account for about five per cent of Canada’s worldwide market.

Because trade is more important than safety.

So Ger, how effective is that ban on mammalian protein in ruminant feed? Got any proof?

Don’t worry, exports won’t be harmed: Another mad cow case in Canada

Gotta wonder just how effective Canada’s ban on mammalian protein in ruminant feed is, given the number of bovine spongiform encephalopathy (BSE) cases there have been over the past decade.

ITALY-G8-G5-AGRICULTURE-FARMWhen there’s a BSE case, or a foodborne illness outbreak like Listeria in the $5.5 billion a year Maple Leaf Foods, government agencies fall over themselves to assure the public – and trading partners – that everything is fine.

Would the Canadian economy sink were it not for the agricultural behemoths? Probably.

The Canadian Food Inspection Agency says little more than a week passed from the time the most recent case of mad cow disease was first suspected to when it was confirmed and national trading partners were notified.

A timeline of the case at an Alberta farm has been released on the agency’s website.

The website says a private veterinarian took samples on February 4 at the undisclosed farm and submitted them to a provincial lab.

It says they were tested on February 6 and the lab recorded a “non-negative” test result.

The lab repeated the test the following day with the same finding and reported the case to the CFIA, where the agency conducted its own test in Lethbridge, Alta, to confirm the result.

The CFIA says it started gathering information on the animal’s herd on Tuesday, officially confirmed the case on Wednesday and posted the case to its website and notified Canada’s trading partners on Thursday.

Agriculture Minister Gerry Ritz said Friday that the infected animal was not born on the farm where it was discovered.

Ritz also said the discovery won’t affect Canada’s international beef trade because it won’t change the county’s controlled BSE risk status from the World Organization for Animal Health. He said Canada has stayed below international protocols that allow for up to a dozen BSE cases a year.

Irealand? Really?Nearly two decades after ban, Irish beef is back in America

Irish beef was served in New York City for the first time in 17 years on Monday night, after a ban in 1998 saw all European beef restricted from entry into America.

ireland.beef.us.feb.15At a swanky event in Manhattan’s Upper East Side, Ireland’s agriculture minister, Simon Coveney, presented a sample of his nation’s beef to a crowd of chefs and food writers, and presented the case for Irish beef filling the huge American demand for red meat.

“The average American eats twice the volume of beef per head to the average European. So you take your beef very seriously,” Coveney said.

“If we are to be serious players in this market, we need to prove to you that we take our beef seriously,” he continued. “And we do.”

Monday’s event was held at Daniel, French chef Daniel Boulud’s two-Michelin-starred restaurant, which prepared a series of dishes with Coveney’s beef as a demonstration of its flavour.

“It does taste a little bit different to US beef,” Coveney told the crowd. Irish cattle are grass-fed, the minister said, and happily for Ireland “the fastest growing segment in the beef market in the US is actually the green beef, or grass-fed”.

The Irish beef last served in the US would be old enough to drive by now, had it the necessary appendages and wherewithal. The US imposed a Europe-wide ban on all beef on 1 January 1998, at the height of the BSE, or bovine spongiform encephalopathy (aka “mad cow disease”) crisis.

Meanwhile, Taiwan’s Economy Minister John Deng (鄧振中) said Wednesday that Taiwan may ease restrictions on imports of American beef amid reports that it will allow in six kinds of beef parts to make it easier to join the U.S.-led Trans Pacific Partnership (TPP) trade bloc.

Deng, who is in Washington, D.C., for a visit, told a CNA reporter in Taipei by phone that the six types of beef under consideration — bone marrow, blood vessels, head meat, cheek meat, weasand and tallow — are not internal organs and therefore not banned by law.

But businessmen have not been willing to import these beef parts for fear of violating the law because the cuts have not been defined and classified clearly enough under the law, he said.

Deng stressed that the government will not open Taiwan to beef internal organs from the U.S. at the expense of public health or in contravention of laws passed by the Legislature.

Norway finds ‘probable’ case of mad cow disease

A second positive test for bovine spongiform encephalopathy (BSE) on a 15-year-old cow reinforced suspicions that it had mad cow disease, the Norwegian Veterinary Institute said.

mad.cows.mother's.milk“We have a likely and strong suspicion of a possible variant of BSE,” Bjørn Røthe Knudtsen of the Food and Safety Authority told public broadcaster NRK.

The authorities however said there was a distinction between the type of BSE caused by cows eating meat-based feed — banned in Europe since 2001 after the British epidemic — and an atypical version which has sporadically appeared in older cows in several European countries in recent years.

A definitive diagnosis can only be made by a European reference laboratory in Britain.

“We take this seriously and we are handling it as if our suspicion were confirmed,” Food and Safety Authority official Solfrid Aamdal said in a statement.