Mad cow as bioterrorism?

Scientists worry that US gov't classification of BSE prions as 'select agents' could hinder research

Jan 15, 2004
Eric Sabo(

As public interest in bovine spongiform encephalopathy (BSE) grows in the United States, strict controls on who is allowed to study it could needlessly slow US research on the disease, contend some prion scientists. That's because as part of the Bioterrorism Preparedness and Response Act that recently took effect, BSE prions are considered “select agents” that require special security arrangements, including background checks on anyone who may have access to this material in the lab.

The measure, which calls for similar precautions on handling some 80 other select agents, is one of an increasing number of safeguards intended to keep potentially dangerous biological materials out of terrorist hands. However, the background checks and inspections necessary have slowed down certification of labs.

And Richard Johnson, a neurologist at Johns Hopkins who coauthored a recent Institute of Medicine (IOM) report on prion research in the United States, said that the regulations are possibly misguided for BSE. “I can think of many agents that are far more dangerous than BSE,” said Johnson. “As a bioterrorism agent, BSE is a loser.”

Still, a number of government officials argue that a biological attack on livestock represents a clear and present danger to America's national security. “Hundreds of pages of US agricultural documents recovered from the Al Qaeda caves in Afghanistan early last year are a strong indication that terrorists recognize that our agriculture and food industry provides tempting targets,” said Sen. Susan Collins (R-Maine) in congressional hearings on agroterrorism on November 19, 2003.

Prion research in the United States is already hindered by a “small, aging, and inadequately funded” infrastructure, Johnson and others charge in the IOM report. The equipment upgrades needed to study BSE are expensive to implement, and only two labs in the United States are currently able to deal with such research, the IOM report states.

Even greater financial support, however, may not be enough to convince some researchers to work under tight security, said Johnson. “The amount of time and methods needed to study BSE scare people off.”

The new regulations on select agents do not prevent US researchers from collaborating with groups in Europe, where much of the research on BSE is conducted. Having already faced an outbreak of mad cow disease, European medical agencies invested heavily in BSE research, but without the same select agent restrictions as the United States.

Jason Shih, a professor of biotechnology and poultry science at North Carolina State University who discovered an enzyme that appears to degrade BSE prions in yeast models, said that he ships his material to a lab in the Netherlands, where the enzyme is tested against live BSE prions. Although he would like to test his own work on BSE at some point, Shih said that the arrangement with Jan Langeveld of the Central Institute for Animal Disease Control in the Netherlands is working out fine. “I am willing to collaborate with anyone who can help,” he said.

Adriano Aguzzi, a leading prion researcher in Switzerland, said that his group is inherently cautious in studying BSE due to the chances that it can be transmitted to humans. “In my lab, we take biosafety very seriously,” said Aguzzi, who is at the Institute of Neuropathology, University Hospital of Zurich. “All handling must be performed by persons who are trained and skilled in biosafety Level 3 procedures.”

Although BSE is clearly dangerous to those who come into contact with it, Aguzzi doubts that terrorists would find prions very useful since it can possibly take decades to cause any real harm. “The malicious introduction of prions into the food chain of humans or of cows would be a terrible scenario,” he said.  “And yet, I continue to believe that a terrorist might probably rather opt for poisons acting with a shorter latency, rather than an agent that may have a hypothetical incubation time of 20 years or longer.”

That BSE can be studied openly in Europe—or for that matter, in a secret lab in any country hostile to the United States—is one of the more pressing challenges in ultimately controlling biological agents, said Dave Franz of the National Agriculture Biosecurity Center at Kansas State University.

“Rules are not going to protect us totally,” said Franz, who still believes that there should be some restrictions on who comes into contact with BSE. In balancing security concerns with the need to move biomedical research forward, he said that the best rule of thumb is openness. “In the end, it comes down to trusting people,” he said.