BSE: Suspected new case in Ireland | Retina scans offer earlier BSE detection

Beef Central, 23/06/2015

The World Organisation for Animal Health has called on the international community not to restrict trade in, or the consumption of, Irish beef following a suspected case of BSE in the country.

Ireland’s Department of Agriculture, Food and the Marine (DAFM) recently announced that a suspected case of the disease had been identified in a five-year-old cow on a dairy farm in county Louth.

The cow was of the Rotbunt breed, which is rare in Ireland, but was reportedly part of a herd that had BSE in the early 2000s.

Further tests are being carried out and results are expected this week. But if confirmed, it would be the first case of BSE (Bovine spongiform encephalopathy) in Ireland since 2013.

The DAFM said the cow was not presented for slaughter and did not enter the food chain.

The case was identified through the department’s on-going surveillance system on fallen animals – that is, animals which die on farm.

A positive result would be a blow for the Irish beef trade, which just last week welcomed the decision by the World Animal Health Organisation to grant the Republic of Ireland a “negligible risk” status in respect of BSE.

Irish farmers have traded under a “controlled” status for almost two decades.

World Organisation for Animals Health deputy director general Dr Brian Evans has told Irish media this week that if BSE is confirmed, Ireland’s risk categorisation will reduce.

But this would not prevent Ireland from trading its beef products internationally.

Dr Evans said safeguards to protect animal and human health were in place in Ireland and working well.

“[The OIE would] reassure countries that, should Ireland’s status move from negligible to controlled risk, this in no way should be taken as an opportunity to restrict the consumption of Irish meat or meat products.”

The Irish Times also reported that Dr Evans said possible changes to the categorisation system were being debated that could mean countries in the negligible risk category would not lose that status in one-off or very infrequent BSE cases.

The OIE, made up of 180 nations, has a three-tier categorisation for BSE in beef products; undetermined risk, controlled risk and negligible risk.

Investigations into the suspected BSE case in Louth are considering the possibility that the five-year-old cow may have contracted the disease from feed eaten years earlier.

BSE cases fell dramatically after meat-and-bonemeal feed was banned and other measures were introduced.

There were no cases of BSE reported last year, for the first time since 1989.

Most animals that died from BSE in recent years were old and had eaten feed containing meat and bonemeal years earlier, so a case involving a five-year-old cow is unusual.

In January, Ireland became the first European country to be granted access to the US beef market following a 16-year ban stretching back to the BSE crisis of the 1990s.

Retina scans allow for earlier BSE detection

New research from Iowa State University shows that BSE in cows can be detected earlier by examining the animal’s retinas.

BSE is an untreatable neurodegenerative disorder caused by misfolded brain proteins known as prions. Classic BSE incubates for years before producers or veterinarians notice symptoms, usually discovered when the animal can no longer stand on its own.

But Heather Greenlee, an associate professor of biomedical sciences in Iowa State’s College of Veterinary Medicine, said studying the retinas of cattle can identify infected animals up to 11 months before they show signs of illness.

“The retina is part of the central nervous system,” Greenlee said. “Essentially, it’s the part of the brain closest to the outside world, and we know the retina is changed in animals that have prion diseases.”

In collaboration with Justin Greenlee’s group at the U.S. Department of Agriculture’s National Animal Disease Center, she recently published findings in the peer-reviewed academic journal PLOS ONE. She began studying how the retina relates to prion diseases in 2006, and the experiments that led to her most recent publication began in 2010.

The experiments utilize electroretinography and optical coherence tomography, noninvasive technologies commonly used to assess the retina. Greenlee said cows infected with BSE showed marked changes in retinal function and thickness.

The results have implications for food safety, and Greenlee said the screening methods used in her research could be adopted for animals tagged for import or export as a means of identifying BSE sooner than conventional methods.

Greenlee said she’s also looking at how similar diseases in other species affect the retina. For instance, she’s conducting experiments to find out if retinal tissue may be a valid means of surveillance for chronic wasting disease in deer.

She said she isn’t ready to publish her results, but the data gathered so far looks promising.

The research also may contribute to faster diagnosis of Alzheimer’s disease and Parkinson’s disease in humans, both of which are caused by proteins folding incorrectly.

“Our goal is to develop our understanding of the retina to monitor disease progression and to move diagnoses up earlier,” Greenlee said. “We think this research has the potential to improve diagnosis for a range of species and a range of diseases.”

Sources: Irish Times/Iowa State University


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