At first, it feels like the flu but the effect is ultimately far worse. And you don't find out until it's too late. The inability of doctors to diagnose a patient's exposure quickly is one of the most troubling aspects of attacks by toxic biological agents like anthrax. At the biannual Army Science Conference, researchers discussed new ways to identify such deadly disease agents more rapidly, while there's still time to treat them successfully, and to warn of imminent attacks.

By the time a pathogen is identified using existing blood-sampling techniques that may take as long as 72 hours to perform, it is could be too late to save the patient. So doctors at the Walter Reed Army Institute of Research are trying to push back the diagnostic clock from days to minutes by measuring changes in a patient's gene patterns that occur soon after exposure to deadly pathogens.

Doctors compare a patient's gene pattern against a library of key gene patterns derived from a diverse group of 75 individuals. In 24 hours, they can detect whether there are significant discrepancies between the patient and the library, which are reliable indicators of exposure to a pathogen. Medical researchers are working on a method to identify these genetic changes within 30 minutes, well before symptoms become apparent, according to Walter Reed researcher Marti Jett.

The new technique does not identify a specific pathogen but instead gives doctors a prompt to begin the identification process earlier than they might otherwise, thereby dramatically reducing the time it takes to pinpoint the pathogen. The ultimate goal is to put this genetic testing method on a chip, so that it can be used by non-medical personnel in the field. One challenge is that each toxin produces its own unique genetic signature in a host, so gene patterns will vary accordingly. And while a chip can be packed with data regarding known pathogens, this technique may not be effective against previously unknown pathogens or against known pathogens that have been somehow modified in a laboratory.

Better yet, of course, would be a warning that a biowarfare attack is imminent. For soldiers in the field, that warning may come from radar. Researchers at the U.S. Army Research Institute, the University of Virginia and the University of Southern California have discovered that radar frequencies in the terahertz range can detect an oncoming cloud of pathogens. To date, the maximum warning time is 85 seconds. While that doesn't sound like much time, it may be just enough of time to don protective gear or seek shelter indoors. --Frank Vizard

Back to Future Combat: Part 1