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Cybernews | SCIENCE WATCH

Anthrax Scare Points Up Need for Early-Detection Technology

March 23, 1998|LEE DYE

Army Maj. Paul Schaudies was far from reassured when he watched from his Pentagon office last month as a biological-warfare scare unfolded in Las Vegas. Two men had been arrested for possession of anthrax, one of the most lethal biological substances on the planet.

What troubled Schaudies, and others working in the field of biological and chemical warfare, was the fact that it took more than two days for authorities to determine that the anthrax was a nonlethal vaccine used for animals and not a serious health threat.

If it had been "weapons-grade anthrax" and released into the atmosphere, those exposed would have been beyond help before authorities knew for sure what they were dealing with.

"So if you make your assessment based on current observations, we aren't real good at this yet," said Schaudies, who recently left his Pentagon post for a position in private industry.

Schaudies' role at the Pentagon was to fund research projects that could sharpen our ability to detect and identify chemical- and biological-warfare materials, so he knows better than most how much progress we are making.

The progress has been significant, he said, especially in the chemical arena. But there is much work to be done, particularly in the detection of microorganisms that can be released in minuscule volumes and take up residence inside the human body, where they grow and multiply.

The time it takes to identify harmful substances is critical, Schaudies said. In many cases, early treatment is simple, whereas delays can prove fatal.

We are furthest along in rapid detection of chemical substances, he added, but many of those techniques are ineffective in the biological realm. One technology that seems promising is mass spectrometry. A spectrometer bombards substances with ionizing energy, such as a laser beam.

The high-energy beam breaks off chunks of molecules into ions, which are atoms with a positive or negative charge. The type of ion produced reveals the nature of the parent molecule, and thus the composition of the chemical--its chemical profile.

But that becomes immensely more difficult with bacteria, because the characteristics change.

"The profile changes as a function of the phase of growth, whether they are actively growing or not growing, and as a function of what they are growing in," Schaudies said. Anthrax growing in milk would have a different profile from anthrax growing in water or anthrax that is in a dormant stage.

William Velander, head of the Pharmaceutical Engineering Institute at Virginia Tech in Blacksburg, Va., is trying to take that technology a step further by wedding a mass spectrometer with something called an affinity sensor.

Velander, a biochemical engineer, and Kent Murphy, a fiber-optics expert at Virginia Tech, say they have developed a system that is 20 times more powerful than previous sensors and can identify a specific microorganism in seconds instead of days.

They attached a mass spectrometer to a fiber-optic system that bombards the target with a laser beam. The resulting ions are allowed to escape from the fibers and into a surrounding polymer layer. The layer contains ligands, molecules that are known to bond chemically with certain materials.

"The ligands are tailored so that they will bond only to a specific target, even in a very complex mixture," Velander said in a telephone interview. "So I could immerse this thing in sewage and they would still bond."

The system is so sensitive, according to Velander, that it could identify substances at concentrations of a few parts per trillion, which puts it at the cutting edge of detection technology.

Such sensitivity is crucial for targets such as anthrax, Velander said, because it takes only a few microorganisms to do damage.

"Some have a doubling time of about every 20 to 40 minutes," he said. "So it becomes a problem very quickly."

Precise identification is critical, he added, because "you've got to treat the victims before they are sick. If you know what they have been infected with, the treatment before they are sick is relatively simple. It's an outpatient therapy."

The most common treatment for anthrax inhalation, for example, is penicillin, but that works only before the symptoms--which resemble the common cold--are acute.

One key weakness applies to every approach. Investigators need to know what they are looking for to have any chance of detecting the harmful agent, and there are literally thousands of microorganisms that could be used in biological warfare. That list has been narrowed by determining which organisms are most easily cultivated and deployed, but if investigators start out testing for the wrong thing, their hopes of success are slim.

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Schaudies also pointed out that sometimes you aren't even aware of a problem until it's too late. And it doesn't require an act of terrorism to produce results similar to biological warfare.

A few months ago, several people in Maryland died before the cause--food poisoning from a church supper--was determined.

Schaudies is now working on an entirely new approach to battling chemical and biological warfare. His aim is to develop a system to warn of danger without necessarily determining the nature of that danger.

"It's similar to sending canaries down into the coal mine," he said. If lethal gas is present in a mine, it will kill the canaries before killing the miners, alerting them to get out.

Schaudies is working on sensors that are a bit more sophisticated than that but designed to do the same thing.

"You want something that is more sensitive than the human body," he said. "It can tell you if there's something present that can affect human functions. It won't necessarily tell you what it is, but it will tell you there's something of concern there."

He said such a system could warn of the presence of chemical or biological threats we haven't even imagined yet.

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Lee Dye can be reached via e-mail at leedye@compuserve.com

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