Since the first two components that the national microbial forensic laboratory will rely upon are addressed in other chapters, the focus here will be on the SWGMGF. The newly formed SWGMGF is hosted by the FBI and has a membership drawn from a wide range of federal agencies, as well as academia. Input from the private sector will be sought on a routine basis. As mentioned above, the SWGMGF is modeled after the successful practices in the human DNA forensic arena (i.e., SWGDAM)30 which utilizes peer consensus to identify and define the criteria on various topics, address technical issues, and set performance guidelines. The Scientific Working Group's success is based on bringing together experienced individuals and organizations (that routinely do not have the opportunity to share and exchange ideas) to foster high-quality, integrated interactions so that challenges related to bioterrorism and biocrimes can be rapidly and effectively addressed. The goals of the SWGMGF are to provide guidance and criteria so that physical evidence can be used to obtain information about the organism or toxin, the persons involved, the places, the processes, the instrumentation, and/or the time of the criminal act.
The missions of SWGMGF are (1) to define criteria for the development and validation of forensic methods for attribution of biological toxins and microbial agents, and (2) to define the needs and criteria for forensic infrastructure and capabilities to support investigation and attribution.
There are many tasks for the SWGMGF to undertake to develop a microbial forensics program and support the mission of the national microbial forensic laboratory. Some may take many years to complete. Because of foundational needs and current funding resource focus, the SWGMGF initially is concentrating on: (1) establishing the criteria for the development and validation of methods to type or individualize various threat agents in ways that can be used forensically to attribute criminal acts, (2) defining quality assurance guidelines, (3) prioritizing research efforts on pathogens and toxins that would most likely be used in biocrimes, (4) understanding and/or enhancing population genetic data so that the significance of a finding is appropriately conveyed, and (5) establishing the design criteria for the various supporting databases. Other topics to be subsequently addressed by SWGMGF include analyses that can further resolve the source of the evidence, such as nonbiological evidence, biological background information (to include pollen, fungi), specific technology needs (to include immunoassays, isotope analysis, mass spectrometry), field testing assays, and host response (such as antibody detection assays).
A primary and immediate focus of the SWGMGF is laboratory quality assurance (QA). Assays carried out in the laboratory need standards of performance for forensic applications. False positive and false negative outcomes and their implications should be understood. Sensitivity and specificity standards should be established. Defined controls and proficiency tests need to be developed. The BFAC will require a valid QA program for operations and to set the standard of performance for the microbial forensic community. Laboratory QA is the documented verification that proper procedures have been carried out by skilled and highly trained personnel in such a way that valid and reliable results can be obtained. When the same methods are used, test reliability implies reproducibility under defined conditions of use and should transcend different laboratories and practitioners. Quality assurance must encompass all significant aspects of the analytical typing process, including organization, management, personnel education and training, facilities, security, documentation of records, data analysis, quality control of reagents and equipment, technical controls, validation, proficiency testing, reporting of results, auditing of the laboratory procedures, and safety. Quality assurance and appropriate guidelines or standards for microbial forensics will be based on human forensic DNA typing standards,31 clinical laboratories' standards,32 and standards of the ISO (International Standards Organization).33 It is important to note that QA guidelines in microbial forensics must retain enough flexibility to accommodate the nature of forensic samples as well as future advancements in technology and molecular biology. The first microbial forensic laboratory QA guidelines document has been published.34
One of the important aspects of the QA program is to develop a set of criteria for the development and validation of methods to type various threat agents in ways that can be used to attribute criminal acts. Validation is a process by which a procedure is evaluated to determine its efficacy and reliability and to determine the operational limits of the technique. Many methods are being developed and need to be developed further (many with government support). Some methods, however, may not have been subjected to quality standards, and no established criteria to guide validation have been established. Quality products need to be developed, and these must have defined performance parameters so that the users can apply the information generated effectively.
An event may occur where methods will be required that have not yet been validated by rigorously defined QA practices. For public security, it will be imperative that investigators make use of these techniques. If the results of one of these less-validated procedures are used for other than investigative leads, then a preliminary validation assessment should be carried out. One could convene a panel of experts, with proper security clearances, to assess the utility of the rapidly developed method and to define the limits of interpretation and conclusions.35 Such an approach has been employed in the field of human DNA forensics for victim identifications in the collapse of the twin towers of the World Trade Center in New York caused by the terrorist acts of September 11, 2001.
Identifying pathogens to focus research efforts is a requisite. Many of the original top-priority biothreat agents were based on agents researched and weaponized in former state-sponsored bioweapons programs. Although, historically, food pathogens such as Shigella dysenteriae, Salmonella typhimurium, and E. coli O157:H7 are readily accessible in nature and have been used,10 little attention has been focused on agriculture, and plant pathogens in particular have been underrepresented in microbial forensic efforts. Although hundreds of potential pathogens and toxins exist, not all of them present the same threat as weapons. While one organism may have a high virulence, it may be very difficult to culture, disperse, or handle. Conversely, an organism with limited destructive potential may be readily available and easy to disseminate. To focus research efforts, it is therefore of crucial importance to outline a set of criteria with which to evaluate the potential threats posed by biological agents. Potential criteria include availability, ease of culture, survivability in the environment, ease of dispersion, infectivity, morbidity, impact on target population, immunity of target, therapeutic control measures, ability to be transmitted subject to subject, and ability to be bioengineered to increase virulence or to make the agent resistant to vaccines or therapeutics. The SWGMGF is considering all of these criteria and has added virulence, the knowledge base forming the foundation upon which biological marker development relies (i.e., state-of-the-art), the likelihood of use of a particular agent, and the impact of the use of the agent on social stability.
Once an organism is identified by whatever means is available, the significance of that finding needs to be conveyed appropriately. One should not interpret evidence beyond the limits of the assay. While inferences can be made without a complete understanding of the genetic diversity of an organism, more data will provide increased resolution toward the goal of attribution. This requires more population genetics and statistics studies. To date little has been done in the context of forensic attribution.
Information is the key to thwart terrorism and may be our best defense. Databases are required to have ready access to information. For a database to be effective, it must contain the appropriate data entry items, and the data must be retrievable. With proper planning, meaningful and useful databases can be developed. The database(s) criteria need to be defined, and SWGMGF is taking on this function as well. Criteria fields for information databases under consideration are: multi-agency threat lists (virus, bacteria, fungi, protozoa, insects, toxins), recognizing synonyms, strain data and virulence, vaccine strains, DNA sequences (whole genomic and partial), bioengineering events, biomarkers, organism sources (laboratory, geographic, and natural), national experts and contact information, laboratory facilities, assays, scientific presentations, literature references and full text, research grants, characteristics (e.g., microscopic morphology, colony morphology), antibiotic resistance, natural transmission, viability (e.g., aerosol, liquid), materials found with microorganisms (e.g., manufacturing process residue/metabolites, culture media, additives for processing, additives for stability), methods of manufacture, handling, packaging, shipping, sources for materials, environmental incidentals (e.g., pollen, fungi), historical outbreaks, known instances of threats or usage, hoaxes, epidemiology, strain and disease history, disease symptoms, dissemination strategies, dispersal strategies, methods for investigation prior to an event, and links to other databases. The Bioforensics Demonstration and Application Project supported by the Department of Energy (DOE) is developing a National Bioforensic Information Encyclopedia and National Bioforensic Evidence Database through the efforts of Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and Northern Arizona University. This effort is coordinating with the SWGMGF to set criteria and functionalities. Obviously, the diversity of data entry items in such databases makes it essential that such databases include heteroformatic components and a relational structure (with appropriate links), in which all of the information on any specific record may not physically reside together. Therefore, one task of the database subgroup of the SWGMGF is also to define and suggest research and development needs for bioinformatic tools of suitable search engines for data retrieval in user-friendly platforms.
EPIDEMIOLOGY (A FIRST STEP IN A MICROBIAL FORENSIC ANALYSIS)
Successful use of a bioweapon may not become apparent immediately. Since it may take days to weeks after exposure for an individual(s) to develop symptoms, the first evidence of an event may well be cases in hospital emergency rooms. However, emergency room personnel may not be the first to detect a problem. Other indicators could be, for example, pharmacists distributing more antibiotics than usual, 911 operators experiencing an increase in health-related distress calls, and funeral homes having increased business.36 Thus, better public health (and agriculture) surveillance is needed. Disease outbreaks, especially suspicious ones, should be evaluated as a potential bioterrorist attack. Epidemiologic tools can assist in differentiating between intentional and natural outbreaks.
An important step in achieving the goals of microbial forensics is the integration of different disciplines. It is important to recognize the role of epidemiology in forensics. A biological crime may be mistaken as a natural event. For events that have already occurred, epidemiologists will often be the ones to gather the data. The epidemiologist addresses the cause of the disease and treatment of the victim/patient. The evidence and data obtained at the initiation of the event also will be crucial for the forensic scientist to continue the investigation further for attribution.
The basic epidemiologic approach in the evaluation of a potential bioterrorist attack or biocrime is essentially the same as that of a natural outbreak.36 The presence of some pathogens will automatically indicate an attack, such as smallpox.35 A naturally occurring disease that is found outside its typical environment may raise suspicion and initiate a forensic investigation, such as a man in Florida contracting pulmonary anthrax with no known contact with livestock and a couple in New York developing plague (although the latter was not the result of a bioattack). Laboratory and clinical data are used to confirm that a disease outbreak has occurred. Then to trace back to the source, aspects of the health surveillance system are used, such as number of emergency visits, laboratory data, pharmacy use, work and/or school absenteeism, or any other data that correlate with an increase in infectious disease. It is obvious that an integrated surveillance system must be established, as it is essential for detection of emerging or reemerging disease. Microbial forensics requires established computerized surveillance networks to track infectious disease outbreaks in real time.35 While some systems do exist, better connectivity is needed. Better integration with the CDC's Lab Response Network and PulseNet (for food pathogens) is essential. In the same light, interaction with the veterinarian, Animal and Plant Health Inspection Service (APHIS), and
Agricultural Research Service (ARS) for agricultural targets should be integrated with law enforcement.
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