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5 Final Thoughts
Pages 81-94

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From page 81...
... This chapter summarizes these comments and the ensuing general discussion among the workshop participants; Table 5-1 provides an overview of the four families of technology.1 THE PUBLIC HEALTH PERSPECTIVE Beth Maldin Morgenthau, assistant commissioner for the Bureau of Policy, Community Resilience and Response within the Office of Emergency Preparedness and Response, New York City Department of Health and Mental Hygiene, said that the key message that came from the public health session was that when faced with a BioWatch Actionable Result (BAR) , decision makers want more information as quickly as possible to help them put that BAR into context.
From page 82...
... 82 TABLE 5-1 Potential Families of Technology for an Autonomous Detection System for BioWatch Nucleic Acid Immunoassays and Genomic Sequencing Mass Spectrometry Signatures Protein Signatures TRL of integrated systems using this TRL 9 TRL 6-plusa TRL 4b TRL 6 technology Noc Required Minimal Required • Less sample may Sample preparation • Cell lysis, nucleic acid • Cell lysis increases • Cell lysis, nucleic improve sensitivity extraction sensitivity acid extraction and specificity Nucleic acids, known Chemical Protein and structural Nucleic acids of and novel signatures epitopes, nucleic acids, targeted agents • Bacteria, viruses, • Bacteria, viruses, toxins of targeted • Bacteria, viruses, fungi, indirect fungi, toxins, agents Detectable agents fungi, indirect detection of toxins chemical agents • Bacteria, viruses, fungi, detection of toxins • Limited by • Limited by direct detection of toxins • Limited to included bioinformatic bioinformatic • Limited to included probes algorithms/ algorithms/ probes databases databases High High Moderate High Sensitivity • Enrichment • Single-copy detection • Some exceed current • May depend on (cfu/m3) strategies are needed for some organisms BioWatch requirements sample complexity for low-titer samples High Moderate Specificity High Moderate • Capable of • Not as high (false positive rate/ • False positive rate of • Near-neighbor single-nucleotide as nucleic acid speciation)
From page 83...
... c Although smaller, less complex samples improve sensitivity and specificity, tiny samples reduce sensitivity, due to the effects of Poisson sampling errors for low-concentration agents. Specificity is reduced once the virus, bacteria, or fungus is fragmented by the ionization process.
From page 84...
... Desired Features of Future BioWatch Technology The main items on public health's wish list for BioWatch were a shortened turnaround time to aid the decision making that must happen in the immediate aftermath of a BAR notification; higher spatial resolution in terms of where an agent was released and at how many sites; characterization that would indicate whether an agent is pathogenic or not, viable or not, weaponized or not, and susceptible to medical countermeasures or not; and an estimate of how much agent was released. Also on the wish list were the ability to access an instrument remotely to obtain instrument-specific performance data that would help put a BAR in context, as well as the ability of the BioWatch detectors to store a sample for additional testing and criminal investigation.
From page 85...
... , and the biohazard detection system (BDS) -- that have provided effective aerosol collection, have demonstrated complex and automated sample preparation, have performed multiplexed nucleic acid analysis, are TRL 8 or
From page 86...
... Thomas Slezak, assistant program leader, Informatics for the Global Security Program, Lawrence Livermore National Laboratory (LLNL) , emphasized that even though BioWatch's PCR-based system may have misidentified Francisella tularensis in field tests, that was a failure of the specific assay, not of the overall design of the BioWatch detection technology.
From page 87...
... He added that the community should consider ideas for better validating highly multiplexed assays, and he said that protein-based technologies are undergoing field validation and are performing well, although much more extensive testing still lies ahead. He was particularly impressed by the ability of Raman-based systems to detect both biological and chemical threats in the atmosphere, and he thought that the single-molecule array-based detection system had potential as well.
From page 88...
... Eisenstadt agreed, reiterating how important it will be to involve laboratorians and public health decision makers early in the development process of these new nucleic-acid technologies. He then noted that the real advantage of genomic sequencing technologies is that they provide the most complete and accurate view of the multiple organisms in the environment and the dynamic sequence space that they occupy.
From page 89...
... Mass Spectrometry According to Charles Kolb, president and chief executive officer, Aerodyne Research, Inc., a strength of mass spectrometry is its ability to characterize both targets and the background -- an important capability because the issue BioWatch faces is not signal-to-noise but signal-tobackground. One way to address that challenge is to concentrate the target as much as possible and to reduce background content, while another is to understand the background as much as possible, and it is at this second approach that mass spectrometry excels.
From page 90...
... "Public health laboratorians spend a considerable amount of effort in tracking down the source of infection and outbreaks, and I am very interested in applying technologies that allow for that capacity." In particular, she noted the potential of mass spectrometry and genome sequencing to provide that type of information, but she also noted that developing and networking well-curated databases will be critical for realizing that potential. In addition, she commented that this detailed characterization would not be needed immediately as part of an autonomous system, but could be provided by the lab-based investigation.
From page 91...
... "If we see them during the test, we have to act on them," she said. "Until we have the confidence in these technologies that the actions are sound based on the fact that the technology works, we are not going to want to go there." Scott Hughes from the New York City Public Health Laboratory added that it is important to share the data from these tests eventually so that he and his colleagues can become familiar with the data and gain confidence in them.
From page 92...
... "Switching out a nucleic acid PCR-based system for any of the other wonderful technologies we heard here is ground zero," he said. "You would have to build a whole new system from scratch and test the whole system in parallel with the existing one." Allen Northrup, chief executive officer of the Northrup Consulting Group, disagreed with this assessment, commenting that one way to improve modularity is to understand the basic operating parameters of the existing system in terms of inputs and outputs and to design replacement modules to fit those parameters from the beginning.
From page 93...
... He noted that there was some concern voiced at the workshop about where information from the BioWatch detectors would go, and he stressed that this is a nonissue, as all information goes to the public health departments in the local jurisdictions. It may happen, he said, that CDC would get the information simultaneously, but he stated clearly that "the information will remain under the control of the state and local public health departments." In commenting on the prime requirements for technology for BioWatch, Walter said that "the last thing we can do is test, get a result, test, get a result, and test again.


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