Strategies for Effective Improvements to the BioWatch System Proceedings of a Workshop (2018) / Chapter Skim
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4 Compatibility of BioWatch Improvements Within the Existing Biological Detection Architecture
4 Compatibility of BioWatch Improvements Within the Existing Biological Detection Architecture
Pages 65-79
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From page 65... ...
A single primer probe is used to screen for each agent, and if a positive reaction occurs, the testing laboratory will run several real-time PCR reactions with additional primer probes to challenge and enhance overall specificity. "Only if the proper combination of primer probe sets is reactive for a given agent will a positive result be considered, and only then will activities commence for the possible declaration of a BioWatch Actionable Result, or BAR, along with its followon notifications and activities," said Dizikes.
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From page 66... ...
These conference calls serve to provide situational awareness at a local and national level and recruit additional resources to further evaluate the implications of the BAR to the larger national preparedness and response community. The ultimate question being investigated, said Dizikes, is whether the BAR represents a public health emergency warranting a local and national response or if the circumstances surrounding the presumptive positive result are explicable as a natural phenomenon and thus do not require triggering response activities, including syndromic surveillance by the local public health apparatus.
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From page 67... ...
As currently designed, BioWatch can only find what it is looking for, he noted. "The holy grail of a biological detection system would be the virtually instantaneous detection and identification of any agent posing a biological threat," said Dizikes.
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From page 68... ...
Opportunities for and Challenges to Deploying BioWatch Indoors This panel session included a presentation by David Silcott, chief executive officer and founder of S3I, on aspects of how bioaerosols behave experimentally in indoor spaces. The other four panelists -- Maureen Sullivan, emergency preparedness and response laboratory supervisor at the Minnesota Public Health Laboratory; Mark Buttner; Toby Merlin; and George Dizikes -- then provided their perspectives on indoor surveillance.
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From page 69... ...
Since 2003, he and his colleagues have conducted dispersion tests in a variety of facilities, producing large data sets on indoor dispersions and millions of hours of continuous run times of real-time optical biological threat detectors. While outdoor releases typically produce trace concentrations of particles, an important lesson from indoor release studies is that release from even small dispersal devices such as a handheld nebulizer produces a concentrated plume of particles that is easily distinguished from ambient particle levels by real-time optical detectors (see Figure 4-1)
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From page 70... ...
Silcott said trigger devices have matured over the past 15 years, getting smaller, more rugged, and less expensive. Current indoor triggers based on optical techniques such as elastic scattering, autofluorescence, and polarized scattering now cost less than $10,000.
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From page 71... ...
In his opinion, detection by a property owner would not trigger a public health or BioWatch Actionable Result until the LRN confirmed the result, but a triggered biosurveillance architecture does give property owners low- to medium-regret actions they can perform to minimize spread while waiting for that confirmatory result. In closing, Silcott said that mature and affordable indoor biosurveillance does exist for property owners.
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From page 72... ...
After several months, the facility management team came back to Sullivan with a consequence plan and was ready to have more productive talks, which eventually led to the conclusion that BioWatch was not right for that venue at that time. Mark Buttner said Las Vegas has been proactive about reaching out to property owners and educating them on bioterrorism release scenarios.
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From page 73... ...
"Eventually, we are going to be involved, which is where the up-front communication comes in," said Sullivan. "There has to be some way that public health is aware of these different technologies that are out in the field." Walter agreed, adding that facility owners need to take advantage of the local BioWatch Advisory Committees.
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From page 74... ...
George Dizikes commented that the best time to deploy a sensor array would be when building a facility, rather than having to adapt a sensor array to the existing layout of a building. The good news, replied Bryden, is that fire suppression and fire-activated HVAC control for fire and smoke spread are already incorporated in many buildings, although it would be necessary to add one of several available low-cost technologies for removing the agent from the fire control system's exhaust plume to prevent releasing the agent into the outdoor environment.
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From page 75... ...
In a perfect world, BioWatch would have continuous, real-time aerosol monitoring that produces quality data at low cost, but quick, high-quality, and inexpensive rarely occur in the same technological package, she noted. The ultimate detection system would also determine if a detected organism was viable and infectious and characterize its antibiotic susceptibility, items that Pettit thought might be feasible using molecular markers.
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From page 76... ...
"I think we are appropriately targeting high-risk areas," she said, "but I do think that increasing event-based surveillance or a more targeted approach to surveillance could help partners really enhance the relationships that we know are very important and that BioWatch has done a great job of enhancing." In terms of the BioWatch process, Pettit said she believes PCR is a suitable technology and that the program is devoting appropriate attention to enhancing PCR testing, multiplexing, and next-generation sequencing to produce more data. What she did not hear much about was how to enhance sample collection to shorten the time between release and response and to support advanced molecular diagnostics to quickly identify index cases in individuals exposed to a biological
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From page 77... ...
The PCR technology used in the system was invented by Cepheid, where Allen Northrup was the chief technology officer at the time, and the technology has processed over several million samples since its installation. He was also the chief executive officer of Microfluidic Systems, which developed over 25 automated airborne detection systems for the Department of Homeland Security for testing as part of the m-BAND program.
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From page 78... ...
Merlin noted that the LRN has experience with such a process that BioWatch can learn from and implement as it develops new technology. Currently, for example, the LRN is in the process of introducing mass spectroscopy to replace a mouse assay for botulinum toxin detection using a full-sized mass spectrometer and an elegant assay developed at the CDC.
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From page 79... ...
"It is easier for us to roll out a new assay because we are detecting events that occur on a regular basis," he said. "We are detecting influenza or Zika or West Nile virus or botulinum toxin, and we can compare the new detection method to the old detection method on actual occurring events.
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