Researchers recently released a cloud of Bacillus subtilis bacteria into the Boston subway system. Thankfully, the bacteria was harmless, and the research was an attempt to see just how a biological agent might disperse through the series of tubes that make up a metropolitan transit system.
Global Biodefense explains how they chose Bacillus subtillis:
Since a portion of the technologies rely on the detection of genetic or proteinaceous materials to positively identify a particular threat agent, the testing simulant must be of biological origin. Bacillus subtilis, or B. subtilis, a soil bacterium which is not pathogenic to humans, will serve as the particulate material for the proposed tests. B. subtilis has been widely studied and is considered an innocuous, food-safe bacterium.
Once the agent was released, sensors all through the tunnels read the dispersal and concentration of the bacteria. Grey sensor boxes at stations read the bacterial concentration, and if it reaches above the background level a red box, called a confirmer, at the end of the station is activated.
A few days after the test, Hultgren tells me the system worked as planned, both detecting and identifying the bacteria. “The confirmer collected a sample and about 30 minutes after the release we had a positive detection of the material at a station over a mile away down the track,” she says.
These tests will run for five more months, tracking things like how weather changes the spread of a biological agent.
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