Bacillus anthracis, or Anthrax
Bacillus anthracis, or Anthrax. Image courtesy Centers for Disease Control.

-Tia Ghose

An air-monitoring program to detect threats like anthrax still hasn’t been rigorously tested or integrated with state and local public health organizations, according to a recent report from the Institute of Medicine and the National Research Council.

The system of sensors, called Biowatch, captures air samples and tests them every 24 hours for genetic traces of biological hazards such as anthrax, botulism, and smallpox. Homeland security officials hastily set up Biowatch during 2003, spurred in part by the anthrax scares that occurred after Sept. 11.

Sensors are now located in more than 30 major cities, but problems have dogged BioWatch since its inception. Upgrades were plagued by delays, and its cost-effectiveness as well as the reliability of test results were questioned.

“What we saw is an organization that reacted rapidly, but in so doing inevitably took shortcuts in the validation process,” Bernard Goldstein, chair of the University of Pittsburgh Public Health School and head of the committee that authored the report, told Elevated Risk.

Seven years after Biowatch’s creation, the same issues linger. DHS insists the system has not yielded any false positives or detections of pathogen DNA when none is present. It adds that Biowatch has generated dozens of “actionable results,” but following evaluation from public health officials, they were deemed not to have been caused by a terrorist attack, the report notes.

In addition, many potentially deadly pathogens may already lurk at background levels in the environment, yet no one knows what those background levels may be. The sensors could be unable to distinguish DNA from lethal bacteria such as anthrax and more benign genetic lookalikes.

Even being alerted to the possible presence of anthrax would not necessarily reduce deaths or illness. The direction of the wind, the amount and type of bacteria, and the density of population may all affect the deadliness of a potential attack, the treatment or approach to prevention, and the extent to which BioWatch is helpful, according to the report.

The exports also noted that BioWatch hasn’t been adequately plugged in to state and local public health departments, many of which already monitor for a wide-range of problems, from salmonella to Ebola. BioWatch was designed to complement such efforts by quickly detecting the few diseases, like anthrax, capable of sickening thousands at a time. To contain damage by treating those exposed within a few days requires close coordination with public health programs and a clear method for responding.

Public health departments don’t know how to interpret BioWatch detection events and typically aren’t equipped to respond to them, the report says. So the committee argues that instead of pouring money into technology supporting the sensors, the program should strengthen its ties to the public-health system.

DHS hopes to upgrade BioWatch to test for pathogens every four to six hours, pinpoint target pathogens more accurately, and expand the number of locations it tests. The current generation of sensors costs about $80 million a year, and the upgrades proposed by DHS in 2008 would raise the price tag to an annual $200 million, according to the report. But it’s not clear that even with the increased investment BioWatch can tackle some basic scientific hurdles.

The proposed enhancements to the BioWatch system are appropriate but very ambitious; they will be possible only if significant advances can be made against long-standing scientific and technical challenges.”

Other federal players, like the Defense Department, have funded efforts to automatically detect airborne biological threats for years. However, the report says, such programs haven’t been all that successful.

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Tia Ghose is a researcher and reporter at the Center for Investigative Reporting and California Watch. Before joining the organization in 2010, she was a Kaiser health reporting intern at the Milwaukee Journal Sentinel. Her work has appeared in, Scientific American, the Salinas Californian, Science News and other publications. She earned a graduate degree in science writing from the University of California Santa Cruz.