Letters laced with anthrax bacteria started showing up in letters delivered by the post office in the wake of 9/11. Five people died. In 2003, the US government launched a $1 billion anti-bioterror program called BioWatch.
And just recently, BioWatch researchers released a cloud of bacteria into a subway tunnel underneath the Boston area. Hal Hodson reports for New Scientist.
It’s 3 a.m., and the subway station has long since shut for the night. A team of researchers from the US Department of Homeland Security (DHS) is testing whether their new detection equipment could work as an early warning system if a deadly agent like anthrax was released into a city's metro network.
After one train leaves, they release a batch of dead Bacillus subtilis bacteria, which go on to form a harmless cloud that wafts through the tunnel towards downtown Boston. The air in front of an inbound train pushes it onward.
About a year ago, BioWatch set up sensors to monitor air around the clock in 30 cities. They’ve been measuring background levels of biological material -- one of the keys to avoiding the false positives that have dogged previous bio-sensing systems.
The gray sensor boxes, called triggers, are atop metal racks at 4 points along this particular platform. Similar commercially available systems count biological particles as they pass through a beam of light inside the box. Anything over the background level will send a signal that activates a bright red box at the end of the station. That’s called a confirmer.
Anne Hultgren with DHS miniaturized the equipment needed to identify DNA – that way, air filters that are collected every day don’t need to be brought into a lab. Now, it all happens on-site with the suitcase-sized box, whenever the triggers detect unusual quantities of a biological agent. They’re aiming to do in 20 minutes what used to take 2 days.
When the next train pulls in to this station, the sensors at the next stop down the line should be able to detect 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," Hultgren explains.
The tests will continue for 5 months, helping the DHS understand how biological agents move around the subway under different conditions, such as when the weather is colder.
The government is currently deciding whether to spend an extra $3.1 billion over the next 5 years to keep the program going.
[From New Scientist]
Image by soelin via Flickr