Q & A
Paper in Proceedings of the National Academy of Sciences
“New Form of Mad Cow Prion Discovered”

What is the significance this paper?

• We have consulted scientific experts who say that this is an interesting study but it will be important to see if other research groups can confirm it. We are told this is from a relatively new research group, so confirmation will be important to the credibility of the research.

Is it likely there are other forms of the BSE prion?

• We don’t know if there are different strains of BSE. This research suggests there are but additional research must be done to confirm this. We do know the mutated proteins that cause Transmissible Spongiform Encephalopathies (TSEs) can have a number of sub-types that cause disease within a particular species. For example, there are several strains of the prion that causes scrapie in sheep. However, if there are different BSE strains, there is no evidence that the characteristics of the disease would be any different.

If this data is confirmed, will this change the way we deal with BSE?

• No. A group of world renowned experts from the Office of International Epizootics (OIE) International Reference Laboratories in England, Switzerland and Japan, as well as experts from Italy, met in December 2003 to review the data on the atypical BSE cases.
  
   
• The OIE experts concluded that the available evidence did not justify any changes in current surveillance methods, in disease control or in measures to protect human health. They also said the risk to animals or humans had not changed and there was no case for changes to international trade rules.
  
   
• The group of experts also said that, while the observations reported had not previously been described, it would require further investigations to clarify the significance. The experts also said that, even if the data did represent the existence of different strains of BSE, this didn’t mean these strains were actually new.

Does this research raise a concern that humans who appear to be suffering from sporadic CJD may actually be infected with the BSE agent acquired from eating beef?

• No. This question has been raised by other research in the past but scientists say that, if this were the case, epidemiological data would show a statistically significant increase in the number of sporadic CJD cases, especially in countries where BSE is endemic and common. This has not been the case. The incidence rate of sporadic CJD in these countries remains consistent with the worldwide average rate of one case per million population per year.
  
   
• It also is important to remember that, just as the United States has firewalls to prevent BSE from spreading among cattle if it is found here, there also are firewalls that protect human health even if BSE were present. The BSE agent has not been found in beef muscle cuts, it is primarily found in the brain and spinal cord. The parts of cattle that potentially could contain infectivity are required by federal law to be removed from cattle at risk for BSE and banned from the human food supply. In addition, any cattle showing possible neurological symptoms and all cattle that are unable to walk are banned from the human food supply.
  
   
• The federal Centers for Disease Control and Prevention has estimated that in the United Kingdom where there have been the most cases of BSE, and where 1,144 cases were diagnosed in 2002, the risk of contracting BSE from eating beef is 1 in 10 billion servings. In a minimal risk country such as the U.S., the risk is either non-existent or so low it can’t be calculated.

Summary of PNAS Paper

EMBARGOED:  NOT FOR PUBLIC RELEASE BEFORE 5 P.M. ET
MONDAY, FEBRUARY 16, 2004

 Selected Article Highlights

* New Form of Mad Cow Prion Discovered

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New Form of Mad Cow Prion Discovered

There's more than one way to make a cow mad. Analysis of Italian
cows revealed a new form of the disease-causing prion. Prions are
infectious proteins that cause devastating and fatal
neurodegenerative diseases, including bovine spongiform
encephalopathy (BSE) in cows and Creutzfeldt-Jakob disease (CJD)
in humans. The prion causes proteins in the brain to go awry,
eventually leaving large holes in the tissue. Humans can acquire
the prion from eating affected cows or may develop the sporadic
form of the disease spontaneously. Until the work of Salvatore
Monaco and colleagues, only one strain of prion had been found in
cows. The scientists analyzed the brains of eight cows that had
tested positive for BSE, and discovered a novel prion variant in
two of the cows. Rather than having the typical holes, the brains
of these two cows had an accumulation of amyloid plaques. In
addition, different regions of the brain were affected.
Interestingly, on a molecular level, the new strain resembles the
prion implicated in many sporadic cases of the human disease.
|Whether some cases of what is currently classified as sporadic
CJD are actually acquired by ingesting the new strain of BSE
prions reported here is unknown.

Article #05777: "Identification of a second bovine amyloidotic
spongiform encephalopathy: Molecular similarities with sporadic
Creutzfeldt-Jakob disease" by Cristina Casalone, Gianluigi
Zanusso, Pierluigi Acutis, Sergio Ferrari, Lorenzo Capucci,
Fabrizio Tagliavini, Salvatore Monaco, and Maria Caramelli

MEDIA CONTACT: Salvatore Monaco, Policlinico G.B. Rossi; tel.
39-045-8074285, fax 30-045-585933, or e-mail
<salvatore.monaco@mail.univr.it

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