Quick detection of airborne bioterrorism pathogens.

In most cases, the prognosis for victims of a bioterrorism attack depends on how quickly antibiotics, vaccines, or other medical treatment can be administered. For example, the survival rate from exposure to the anthrax bacterium is high when antibiotic therapy can be administered before symptoms appear, but after symptoms manifest, the survival rate diminishes significantly. Treatment options can't be determined, however, until the pathogen has been accurately identified. A quick turnaround time can thus save lives.

To increase the speed with which pathogens are identified, researchers from Lawrence Livermore and Los Alamos national laboratories have developed a technology known as BASIS, or the Biological Aerosol Sentry and Information System. Designed for indoor or outdoor use at high-visibility events or around likely terrorist targets, BASIS won a 2003 R & D 100 Award.

BASIS has three major components. Aerosol collection hardware continually collects, time-stamps, and stores samples. A mobile field laboratory analyzes DNA from the samples and can identify and characterize a threat organism in less than half a day with a virtually zero false-alarm rate. Software designed by the BASIS team controls and integrates the operations.

The air samplers, called distributed sampling units (DSUs), suction air through filters that have microscopic-size pores and collect any regional microbes onto the filters' surface. DSUs are locked and password-protected to prevent unauthorized access and to guarantee the integrity of filters.

A semi-automated mobile field laboratory analyzes each filter, searching for DNA from target pathogens--those organisms identified by the CDC as high-priority threat agents. Inside the field lab, DNA is amplified via polymerase chain reaction (PCR), a quick, reliable method for detecting DNA of specific microbes. Should a target pathogen be present, the PCR amplifies its DNA while ignoring DNA from other microbes.

To confirm a positive finding and identification of the organism, the laboratory analyzes the target sample a second time. The characterization is so precise that a microbe often can be identified down to the strain level. The suspect DNA then can be sequenced to determine if genetic engineering has, for example, increased a microbe's virulence or has in any way engendered drug resistance.

When a positive identification has been confirmed, the field lab immediately notifies the appropriate response agencies. The entire process--from collecting samples to identifying a threat organism--typically requires only eight to 10 hours.

According to Dennis Imbro, the principal investigator for Livermore's BASIS effort, false alarms have the potential to cause immense disruptions and panic among civilians. Therefore, a primary goal in developing BASIS was to achieve a virtually zero rate of false-positive detections. To date, no false-positive events have been generated by deployed systems.

The BASIS software package runs on a standard laptop computer. The software is divided into two modules: the BASIS Operations Center (BOC) control package and the Sample Management System (SMS) filter-tracking package. The SMS uses bar codes to track filters at every point of the operation--from preparing a filter to processing the final results in the field laboratory. Each DSU can receive operational parameters via shielded cable, radio frequency, or cellular modem and can transmit them in real time to a BOC laptop.

BASIS was first deployed in the month following the September 11 terrorist attacks. It was also deployed in Salt Lake City, Utah, for the 2002 Winter Olympic Games. BioWatch, a derivative of BASIS, is now deployed in major cities nationwide under the auspices of the Department of Homeland Security. BioWatch features elements of the BASIS technology but, instead of a mobile laboratory, uses laboratories that are part of the federal Laboratory Response Network operated by CDC.

For more information, contact Dennis Imbro by phone at [phone] or by e-mail at [e-mail].

(Adapted, with permission, from Science & Technology Review, October 2003, UCRL-5200-03-10, a publication of the University of California, Lawrence Livermore National Laboratory, and the Department of Energy, under whose auspices the work was performed; acknowledgement is given to the U.S. government's right to retain nonexclusive, royalty-free license in and to any copyright covering this material.)