Sniffing Out Bioterror Threats
As anthrax scares multiply -- from New York to Washington, from Germany to Kenya -- the key to quickly detecting this potentially lethal pathogen in the field might reside in a surgical intensive-care unit in Philadelphia. At the Hospital of the University of Pennsylvania, Dr. Bill Hanson uses an old-fashioned twist to make diagnoses: He applies the smell test.
This is no ordinary smell test, however. Hanson has deployed a fleet of "artificial noses" to help spot pneumonia in patients recovering from surgery.
Made by Cyrano Sciences, the $8,000 machines use tiny channels woven into a carbon matrix that absorbs gases. By passing a slight electrical charge through the matrix and calculating the resistance, the nose can detect a wide variety of chemical substances, including the various bacterial elements that represent common causes of pneumonia. And by attaching the device to the breathing tubes of the critically ill, doctors can gain valuable real-time insight into what's going on inside the lungs.
The artificial nose is only one of a host of technologies scientists are actively examining as mechanisms to warn of biological attacks. They range from the obscure to the super high-tech.
Researchers in Montana are studying the possibility of monitoring changes in insect behavior to get early warnings of chemical or germ contamination. A Seattle-based company, Research International, has built a device the size of a portable vacuum cleaner that can detect small amounts of the dangerous E. coli bacteria in food. And Cepheid, a biotech concern in Sunnyvale, Calif., is building backpack-size DNA labs that could sequence the genetic code of pathogens in less than an hour.
Development of customized protective measures, even quick vaccines, could soon follow. "I could see a day when we have a tricorder device, like they have on Star Trek, that could smell a person and make a diagnosis," says Hanson.
Since the Persian Gulf war, when some British soldiers took ill -- fueling fears Saddam Hussein had used biological weapons -- the U.S. government has stepped up efforts to fund research in this area. More than $300 million in 2001 has been spread among the Defense Dept., the Energy Dept., the National Institutes of Health, and the Centers for Disease Control & Prevention. Those efforts will likely be redoubled as hundreds of millions of dollars in additional funds pour into biowarfare research over the next few years.
The dividend to humanity could prove significant in terms of improving medical care. Witness the potential of the Cyranose. The software that powers the handheld device also can "learn" the footprints of new substances and store hundreds of them in a database. The Cyranose is now used only for pneumonia detection and diagnosis of bacterial sinusitis, but experts say it could be converted for use as a versatile biowarfare testing device able to give quick field assessments.
"For any given bacteria, we create a fingerprint of the off-gases that that bacteria produces," explains company CEO Steven Sunshine. "On future analysis, we can look at how close metabolites are for a sample to the library that we have created for that bacteria."
At the University of Texas at Austin, a scientific team has created an artificial tongue that could be used to similar effect. The tongue consists of a silicon wafer containing the equivalent of hundreds of tiny test tubes. In each tube is a tiny bead that changes color when exposed to various chemical compounds. Using a highly sensitive camera to record the color changes that occur when dissolved chemicals are washed into the microscopic test tubes, the scientists can program a computer to study the patterns that emerge and build a color library of chemical footprints.
Most pathogens leave a unique chemical signature that can be used to accurately identify them. That insight could pave another way to get quick diagnoses of smallpox, tuberculosis, or other potentially serious ailments. "From the initial inception, the thought was: The things to target would include chemical or biological warfare agents," explains Dr. Dean Neikirk, a member of the artificial tongue team.
Neikirk and others caution, however, that much work still needs to be done before the technologies will be effective and economical. Furthermore, developing accurate detectors that could continuously monitor air quality in the same manner as smoke detectors remains problematic.
Take the case of anthrax, which could be dispersed in airborne particulate form in a variety of ways. Early warning is particularly crucial with this disease, since the period between the onset of symptoms and death is only a few days -- making immediate treatment imperative.
Anthrax spores could prove hard to detect in real time because they aren't biologically active until they land and begin to reproduce, either in the skin, lungs, or stomach. "One of the difficulties with biothreat agents is that they are not gases but particles," says Neikirk.
Imagine trying to find anthrax particles blowing through a city's air. Neikirk explains: "The fundamental problem is the number of organisms or molecules per unit volume of the air is extremely small. In some cases, you might be looking for one per cubic meter. You have to suck a cubic meter of air through something and catch every particle in there. That's certainly a challenge."
Scientists are already racing to tackle these issues, however. And over time, such technologies will likely prove to be cost-effective. For example, Cepheid's portable DNA testing unit could well revolutionize genetic evaluations and allow scientists to do it in the field for faster results. Both the artificial tongue and Cyranose could be used to ensure purity of processed food or chemicals. And they will likely be more lucrative areas in the near term. According to Cyrano, the market for sensory and vapor analysis is already $8 billion.
At the Hospital of the University of Pennsylvania, in a health-care setting that's far from the biowar front lines, the artificial nose devices are already saving money as well as lives. According to Hanson, physicians are using Cyranose to more quickly diagnose pneumonia and better target antibiotic treatments, as well as to avoid having patients pay for unnecessary laboratory work.
In some cases, the Cyranose provides critical information. "We can't always distinguish pneumonia from lung collapse just based on an X-ray. The one thing you want to treat with antibiotics, the other you don't," explains Hanson.
Meanwhile, a North Carolina company plans to release the first home-based anthrax test system that can identify spores collected from the air, water, or surface areas. The system is expected to cost no more than $25 and will be available at Ace Hardware Stores by Thanksgiving. It will require, on average, 48 hours to give a proper indication of presence of the pathogen. When biowarfare detection makes it to Ace, you know it's quickly entering the mainstream.
By Alex Salkever in New York
Edited by Douglas Harbrecht
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