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An interview with Dr. Christine Musahl of Swiss-based BSE test-maker Prionics, on the state of testing and surveillance, the challenges ahead and the need for a more rational global response to the disease.

Those were among the first words Dr. Christine Musahl heard from Alberta beef producers upon arriving from Prionics headquarters in Schlieren, Switzerland, to promote the company's Bovine Spongiform Encephalopathy (BSE) tests in the heart of Canada's cattle country.

"We spent an entire week talking to a lot of cattle producers and representatives of the beef industry organizations, and what we found is great interest in our testing, but also great stigmatization and even a little fear surrounding the process," says Musahl, Area Director (Canada) for Prionics, a leading BSE test developer. "When someone told us 'help us demystify this disease,' it summed up the general feeling of the need for education and openness to overcome this stigmatization and deal with this disease rationally."

Erasing the stigma surrounding BSE is also a key hurdle for companies like Prionics, which develops BSE tests for the global market. If the dire implications of a positive test for BSE were unclear to anyone in the Canadian beef industry before May 20, 2003, they certainly were not in the weeks and months that followed. While BSE presents a clear need to protect public health and provide BSE-free quality assurance in beef products - and testing as part of surveillance is a crucial component of that effort - exactly which tests and what level of surveillance to adopt is understandably a question of great concern. It's also a difficult one to discuss and deal with openly and rationally, given the tremendous economic, emotional and political pressure surrounding the disease.

For these reasons and to gain a marketing beachhead in Canada, Musahl and colleagues from Prionics returned to southern Alberta soon after their initial visit, to host a major one-day seminar, "BSE: Situation. Science. Solutions," billed as an educational seminar featuring leading international BSE experts. On the eve of the seminar, Musahl, who chaired the session, sat down with Meristem Land and Science to discuss the state of BSE testing and surveillance, the challenges ahead and the need for a more rational global response to the disease.

Interview: Seven questions for Dr. Christine Musahl

Q: We hear a lot of debate about the need for BSE testing and the extent of testing required, but far less about the tests themselves. What are the key types of tests available today, how do they work and how do they compare?

A: If you look at the BSE testing technologies currently on the market, the principle behind each is the same. You have this prion protein, which is what causes the development of the BSE pathogen. Somehow, through the disease process, this prion changes its three-dimensional structure. We do not really know how that is triggered, but we know the structure is altered, and this altered structure gives the protein different properties.

One of the properties that the disease altered prion protein has is resistance to destruction by a protein, called "Proteinase K," which digests the normal, disease-free form of the protein. In all the tests, a sample of the brain of the cow is treated with this Proteinase K, and the test is conducted to detect whether any protein remains. If some prion protein remains, it is obviously resistant to Proteinase K and is therefore the disease-related prion protein.

The difference between the various tests is in the method by which this remaining protein is detected. Currently, there are two major types of tests - those based on western blot technique and those that use ELISA techniques.

Western blotting is a more advanced technique. With western blotting, not only do you get a signal or no signal, you get qualitative information on any signal returned, so you can determine the accuracy of that signal. With an ELISA test, you have a matrix that digests the target protein and delivers a signal if any prion protein remains.

Put more specifically, the ELISA technique provides information on only one feature of the protein contained in the sample. It doesn't tell the tester that the test has functioned properly or if the detected substance was really prion protein. By contrast, the western blot technique provides information on several independent features of the protein, comparable to a fingerprint. It tells the experimenter whether the test has functioned properly and whether the result is negative or positive. As a result, while you can get false positives with the ELISA test, you don't get them with the western blot test.

Q: In Canada, given what the beef industry has been through the past year, the "shoot, shovel and shut up" approach doesn't seem like such a bad way of dealing with suspected BSE. Obviously, that's not an acceptable option. What type of testing approach would you recommend for a country like Canada?

A: Prionics supplies both western blot as well as ELISA-based tests, and there are different advantages to each. The Prionics-Check Western is a western blot test suited for routine use. It is easy to handle and delivers a result in only few hours. It's still a similarly rapid test and the cost is about the same as an ELISA-based test. In January, the Canadian Food Inspection Agency (CFIA) selected the Prionics-Check Western test for Canada's test enhanced BSE surveillance program. The Prionics-Check Western was a test Canada first used during the 2003 BSE investigation, and three CFIA laboratories have now been equipped with it.

ELISA is a viable technology that is even a little less complexe and time consuming than the western blot, but the impact is neglectible. The technology is easy to use and it is good for handling very high testing volumes of several thousand samples a day. ELISA does have the problem of false positives, but this isn't a big issue in countries that have already had numerous cases of BSE reported. In summary, an ELISA is a system that is very well suited for a country where you know you have a considerable BSE problem and a false positive result wouldn't alienate consumers and pose a problem.

But in a country where you don't have BSE or you have very, very low incidence, such as Canada and the U.S., we recommend the Prionics-Check Western over our ELISA test to eliminate the insecurity that false positive results would create. New Zealand and Australia are examples of countries which use the Western Blot exactly for this reason. They are BSE free and they do not want any doubtful results.

For the future, we're working on a third generation test that is already under validation by the EU. This is a test that is based on a dipstick method, which would be the "Rolls Royce" of tests in terms of its superior speed, simplicity and low instrumentation. We expect approval of this test in the EU within the next year.

Q: The business side of BSE solutions is an intriguing one. What's the market like for BSE tests and where does Prionics see itself on the competitive playing field?

A: Prionics is the market leader in BSE tests. In the last years (since 2001), approximately 30 million BSE tests were performed worldwide and over 18 million of these were performed using the Prionics-Check western test, which is based on the western blotting technique. Prionics also supplies an ELISA-based test, the Prionics-Check LIA . Prionics was the first to bring a western blot test to the market.

In terms of market stability, the major market for Prionics has been Europe, which currently tests all animals over 30 months of age, and we think this volume of testing will persist for at least three to five years. The issue of consumer confidence is still that present, that testing is required.

After the BSE cases found in the U.S. and Canada, it's likely more countries will establish surveillance programs. That is also what the world animal health authority OIE recommends.

In recent months, there has also been a new strain of BSE found in Italy. This new strain is one that currently can only be detected with the western blotting technology.

Q: BSE was portrayed initially as a food safety issue, but many in Canada's beef industry and elsewhere feel it's largely become a political one. As a science-based company with clear business interests in the outcome, how does Prionics approach the question of what level of surveillance and testing is required?

A: We advocate a science-based approach. Reasonable is to test the populations that would be infected with the utmost probability if the disease has already spread.

In Canada, under its current process, the CFIA is testing 8,000 animals this year and 30,000 next year, which I think is a population that makes some sense. Generally, Canada has been in a leading position on the American continent with its surveillance progress. In addition, from what I have seen Canada is also far advanced in establishing cattle tracking systems compared to other countries like the U.S.

For surveillance, Canada has concentrated its testing on the famous "4D" animals: the diseased, the downers, the disabled and the distressed. This makes a lot of sense. Prionics worked with different governments at the beginning of the BSE epidemic in Europe, and we found that looking at these high risk animals, the incidence of disease in those four groups is the highest and by far the most relevant. Quite logically you can imagine that if a cow dies because it broke its leg, there might be a reason other than just an accident that it broke its leg. It might be missing co-ordination, and that missing co-ordination might be the result of BSE.

It's important to remember testing is not the measure that gives you risk management. Risk management includes actions such as the removal of risk materials from the food chain and using appropriate feeding procedures.

Testing will give you an idea of where the disease is in the population, and it will then give you an idea of whether you really have a food safety problem. If the results of surveillance uncovers more BSE cases, this points to a need for more testing. But based on the surveillance that's been done, I am not able to judge if you have a food safety problem in Canada and the U.S. And I say that as the area director of a company that on the surface you would say is supposed to sell a lot of tests. As a science-based company; however, that's the way we see the question and that's what we base our recommendations on.

Q: With the way the world views BSE today, it's amazing the damage one infected animal can do to an industry. Since the incident of May 2003 and even before that, the feeling has come up often in Canada that the world needs a more rational way to deal with this disease.

A: That's a very good point, but it's also a very difficult point. If you look at BSE from a rational point of view, you have to realize that there are far more people dying of E. coli and salmonella, and many other diseases. The problem is that BSE can greatly affect the consumer image of beef, a product that is supposed to be very healthy, very good, very American and very Canadian. In Europe, it's also a very expensive product.

BSE affects the economy in such a way that the science around the issue at some point doesn't play a role anymore. It's an economic problem and it's a political issue, and that often deflates the science.

For example, the approach of testing every animal including the very young ones has no scientific rationale. It's a consumer strategy, and that's a valid approach if you state it as such.

An interesting model is Switzerland, which does not have required testing for animals over 30 months of age, but does have targeted surveillance of the food chain from the point of slaughter. Then, in addition, Switzerland allows voluntary testing. McDonalds, and the big Swiss retailers voluntarily have their beef tested in government-inspected facilities. The cost of this testing shows up in the price of beef, but if you look at the beef price in Europe, a kilogram of good beef can cost between $60 and 80 Canadian, so if you add 50 cents to that price for the tests, it doesn't really make a big impression on consumers.

Q: Your Web site describes Prionics as primarily a developer of BSE tests, but also as a company that has evolved into a "competence centre" on prion diseases. What role does education - as exemplified by the Prionics-hosted BSE seminar - play as part of Prionics' marketing approach?

A: Customer understanding of the science of the situation and the scientific and technical rationale behind our products is essential when dealing with BSE. We're relatively new in Canada and we see ourselves as a partner and as a competence centre - as a very knowledgeable and very competent company that can contribute to solving the problem. We're a small, young company of just 100 people, but we're very strong on providing governments and the industry with the necessary scientific and logistic know how rather than just selling BSE test kits.

We were the first company to have a BSE test on the market. Our two CEOs are renowned prion scientists and they have impressive track records. Out of the 100 people we have on staff, around 70 have scientific backgrounds. I'm a good example. I have a PhD in molecular biology and I did my post-doctorate work in prion research, so I know my way around prions.

At Prionics, our interest is not to just sell tests. We want to establish ourselves as a partner that can help all involved parties with the experience and knowledge we have to deal with the BSE challenge in a rationale, science-based manner.

Q: At least at a consumer level in Europe and North America, the hype surrounding BSE seems to have died down and a more reasoned perception of the disease threat has taken hold. What do you see on the horizon?

A: I think we are getting a better handle on this disease. As we implement reasonable surveillance programs, we realize more and more that this is indeed a worldwide problem. I don't think we will really erase BSE as a concern, but I think that we will get it to a low level of concern. We'll accomplish this not only through testing, but also through risk-management measures. Public perception will shift as the science messages get out and erode the stigma surrounding BSE. We will get a grip on it, but we'll always need a level of surveillance to keep that grip.

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Interview: Seven questions for Dr. Christine Musahl

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