Biological warfare against crops

Application of multi-criteria decision analysis techniques and decision support framework for informing plant select agent designation and decision making

The United States Department of Agriculture (USDA) Division of Agricultural Select Agents and Toxins (DASAT) established a list of biological agents (Select Agents List) that threaten crops of economic importance to the United States and regulates the procedures governing containment, incident response, and the security of entities working with them. Every 2 years the USDA DASAT reviews their select agent list, utilizing assessments by subject matter experts (SMEs) to rank the agents. We explored the applicability of multi-criteria decision analysis (MCDA) techniques and a decision support framework (DSF) to support the USDA DASAT biennial review process. The evaluation includes both current and non-select agents to provide a robust assessment. We initially conducted a literature review of 16 pathogens against 9 criteria for assessing plant health and bioterrorism risk and documented the findings to support this analysis. Technical review of published data and associated scoring recommendations by pathogen-specific SMEs was found to be critical for ensuring accuracy. Scoring criteria were adopted to ensure consistency. The MCDA supported the expectation that select agents would rank high on the relative risk scale when considering the agricultural consequences of a bioterrorism attack; however, application of analytical thresholds as a basis for designating select agents led to some exceptions to current designations. A second analytical approach used agent-specific data to designate key criteria in a DSF logic tree format to identify pathogens of low concern that can be ruled out for further consideration as select agents. Both the MCDA and DSF approaches arrived at similar conclusions, suggesting the value of employing the two analytical approaches to add robustness for decision making.

Global Catastrophic Threats from the Fungal Kingdom : Fungal Catastrophic Threats

The fungal kingdom poses major catastrophic threats to humanity but these are often unappreciated and minimized, in biological threat assessments. The causes for this blind spot are complex and include the remarkable natural resistance of humans to pathogenic fungi, the lack of contagiousness of human fungal diseases, and the indirectness of fungal threats, which are more likely to mediate their destructive effects on crops and ecosystems. A review of historical events reveals that the fungal kingdom includes major threats to humanity through their effects on human health, agriculture, and destruction of materiel. A major concern going forward is the likelihood that physiological adaptations by fungal species to global warming will bring new fungal threats. Fungal threats pose significant challenges specific to this group of organisms including the potential for intercontinental spread by air currents, capacity for rapid evolution, a paucity of effective drugs, the absence of vaccines, and increasing drug resistance. Preparedness against bio-catastrophic risks must include consideration of the threats posed by fungi, which in turn requires a greater investment in mycology-related research.

A Systems Approach to Agricultural Biosecurity

This article highlights the importance of systems approaches in addressing agricultural biosecurity threats. On the basis of documentary analysis and stakeholder interaction, a brief survey of agricultural biosecurity threats and vulnerabilities from global and Indian perspectives is provided, followed by an exploration of technological and institutional capabilities. Finally, a perspective on the agricultural disease diagnostic networks is provided, drawing instances from global developments. Technical barriers to agroterrorism are lower than those to human-targeted bioterrorism, and the sector is unique as even a very small disease outbreak could prompt international export restrictions. Key vulnerabilities in the agriculture sector stem from, among others, the structure of agricultural production; insufficient monitoring, surveillance, and controls systems at the borders and in the food chain; inefficient systems for reporting unusual occurrences and outbreaks of disease; and lack of sufficiently trained human resources capable of recognizing or treating transboundary pathogens and diseases. An assessment of technology and institutions pertaining to crop and animal protection management suggests certain gaps. Investment in developing new technologies for civilian application in agriculture, as well as for legitimate actions pertaining to defense, detection, protection, and prophylaxis, and in upgrading laboratory facilities can increase the agricultural sector's level of preparedness for outbreaks. To address potential threats and vulnerabilities of agroterrorism effectively requires the development of a comprehensive strategy and a combined, interagency approach, ideally on an international level. It is proposed that a systems-oriented approach for developing knowledge and innovation networks and strengthening skills and capacities would enable a more resilient agricultural biosecurity system.

The weapon potential of human pathogenic fungi

With the exception of Coccidioides spp., human pathogenic fungi are not found among lists of microbes with potential for biological warfare and bioterrorism against humans. However, many human pathogenic fungi are easily obtainable from the environment, are highly dispersible and can cause significant disease after inhalation with relatively low inocula. When the biological and pathogenic attributes of certain human pathogenic fungi are considered using a formula for calculating the relative weapon potential of a microbe it is as apparent that some organisms such as Coccidioides spp. are comparable to other microbes for which there is significant concern. Our analysis suggests that the current indifference to fungi as potential biological weapons against human populations is probably a perception engendered by their non-communicability, lack of history of use or development as biological weapons, and a relatively low incidence of symptomatic disease following natural infection. Awareness of the weapon potential of human pathogenic fungi is an important consideration for greater preparedness against the threat posed by biowarfare and bioterrorism.

Plant pathogen forensics: capabilities, needs, and recommendations

A biological attack on U.S. crops, rangelands, or forests could reduce yield and quality, erode consumer confidence, affect economic health and the environment, and possibly impact human nutrition and international relations. Preparedness for a crop bioterror event requires a strong national security plan that includes steps for microbial forensics and criminal attribution. However, U.S. crop producers, consultants, and agricultural scientists have traditionally focused primarily on strategies for prevention and management of diseases introduced naturally or unintentionally rather than on responding appropriately to an intentional pathogen introduction. We assess currently available information, technologies, and resources that were developed originally to ensure plant health but also could be utilized for postintroduction plant pathogen forensics. Recommendations for prioritization of efforts and resource expenditures needed to enhance our plant pathogen forensics capabilities are presented.

The Microbial Rosetta Stone Database: a compilation of global and emerging infectious microorganisms and bioterrorist threat agents

BACKGROUND

Thousands of different microorganisms affect the health, safety, and economic stability of populations. Many different medical and governmental organizations have created lists of the pathogenic microorganisms relevant to their missions; however, the nomenclature for biological agents on these lists and pathogens described in the literature is inexact. This ambiguity can be a significant block to effective communication among the diverse communities that must deal with epidemics or bioterrorist attacks.

RESULTS

We have developed a database known as the Microbial Rosetta Stone. The database relates microorganism names, taxonomic classifications, diseases, specific detection and treatment protocols, and relevant literature. The database structure facilitates linkage to public genomic databases. This paper focuses on the information in the database for pathogens that impact global public health, emerging infectious organisms, and bioterrorist threat agents.

CONCLUSION

The Microbial Rosetta Stone is available at http://www.microbialrosettastone.com/. The database provides public access to up-to-date taxonomic classifications of organisms that cause human diseases, improves the consistency of nomenclature in disease reporting, and provides useful links between different public genomic and public health databases.

Microbial forensics: the next forensic challenge

Pathogens and toxins can be converted to bioweapons and used to commit bioterrorism and biocrime. Because of the potential and relative ease of an attack using a bioweapon, forensic science needs to be prepared to assist in the investigation to bring perpetrators to justice and to deter future attacks. A new subfield of forensics--microbial forensics--has been created, which is focused on characterization of evidence from a bioterrorism act, biocrime, hoax, or an inadvertent release. Forensic microbiological investigations are essentially the same as any other forensic investigation regarding processing. They involve crime scene(s) investigation, chain of custody practices, evidence collection, handling and preservation, evidence shipping, analysis of evidence, interpretation of results, and court presentation. In addition to collecting and analyzing traditional forensic evidence, the forensic investigation will attempt to determine the etiology and identity of the causal agent, often in a similar fashion as in an epidemiologic investigation. However, for attribution, higher-resolution characterization is needed. The tools for attribution include genetic- and nongenetic-based assays and informatics to attempt to determine the unique source of a sample or at least eliminate some sources. In addition, chemical and physical assays may help determine the process used to prepare, store, or disseminate the bioweapon. An effective microbial forensics program will require development and/or validation of all aspects of the forensic investigative process, from sample collection to interpretation of results. Quality assurance (QA) and QC practices, comparable to those used by the forensic DNA science community, are being implemented. Lastly, partnerships with other laboratories will be requisite, because many of the necessary capabilities for analysis will not reside in the traditional forensic laboratory.

Biowarfare as a biopolitical icon

Nuclear warfare threat has been one of the main driver for cultural, political, economical and social changes in the late twentieth century, biological warfare threat is about to take it over. However, while nuclear warfare was a concrete possibility, biological warfare is just an elusive risk. This paper will explore some reasons for this apparent inconsistency by discussing biowarfare from a symbolic point of view, looking for its inner meanings and philosophical implications.

Molecular diagnostics in an insecure world

As of October 2001, the potential for use of infectious agents, such as anthrax, as weapons has been firmly established. It has been suggested that attacks on a nations' agriculture might be a preferred form of terrorism or economic disruption that would not have the attendant stigma of infecting and causing disease in humans. Highly pathogenic avian influenza virus is on every top ten list available for potential agricultural bioweapon agents, generally following foot and mouth disease virus and Newcastle disease virus at or near the top of the list. Rapid detection techniques for bioweapon agents are a critical need for the first-responder community, on a par with vaccine and antiviral development in preventing spread of disease. There are several current approaches for rapid, early responder detection of biological agents including influenza A viruses. There are also several proposed novel approaches in development. The most promising existing approach is real-time fluorescent PCR analysis in a portable format using exquisitely sensitive and specific primers and probes. The potential for reliable and rapid early-responder detection approaches are described, as well as the most promising platforms for using real-time PCR for avian influenza, as well as other potential bioweapon agents.

One foot in the furrow: linkages between agriculture, plant pathology, and public health

Plant pathology is a field of biology that focuses on understanding the nature of disease in plants as well as on more practical aspects of preventing and controlling plant diseases in crop plants that are important to agriculture. Throughout history, plant diseases have had significant effects on human health and welfare. Several examples, in both historical and contemporary contexts, are presented in this review to show how plant pathogens, biotechnology, and farming practices have affected public health. Specific topics illustrating clear linkages between agriculture and human health include allergens in the environment, food-safety and agricultural practices, mycotoxigenic fungi, agrobioterrorism, and the biological control of plant diseases. The further argument is made that in order to monitor and ensure that good health and safety practices are maintained from "farm to fork," public health specialists may benefit from the resources and expertise of agricultural scientists.

Aerobiological, ecological, and health linkages

Aerobiology is an interdisciplinary science representing the presence and movement of biological particles in the earth's atmosphere. As an important component of air quality, the impact of these particles on human populations and agriculture were discussed in terms of the ecology of the landscape targets involved. The role of aerobiology in air quality studies was considered.

The threat of plant pathogens as weapons against U.S. crops

The U.S. National Research Council (NRC) concluded in 2002 that U.S. agriculture is vulnerable to attack and that the country has inadequate plans for dealing with agricultural bioterrorism. This article addresses the vulnerability of U.S. crops to attack from biological weapons by reviewing the costs and impact of plant diseases on crops, pointing out the difficulty in preventing deliberate introduction of pathogens and discovering new disease outbreaks quickly, and discussing why a plant pathogen might be chosen as a biological weapon. To put the threat into context, a brief historical review of anti-crop biological weapons programs is given. The argument is made that the country can become much better prepared to counter bioterrorism by developing a list of likely anti-crop threat agents, or categories of agents, that is based on a formal risk analysis; making structural changes to the plant protection system, such as expanding diagnostic laboratories, networking the laboratories in a national system, and educating first responders; and by increasing our understanding of the molecular biology and epidemiology of threat agents, which could lead to improved disease control, faster and more sensitive diagnostic methods, and predictions of disease invasion, persistence, and spread following pathogen introduction.

Advances in molecular-based diagnostics in meeting crop biosecurity and phytosanitary issues

Awareness of crop biosecurity and phytosanitation has been heightened since 9/11 and the unresolved anthrax releases in October 2001. Crops are highly vulnerable to accidental or deliberate introductions of crop pathogens from outside U.S. borders. Strategic thinking about protection against deliberate or accidental release of a plant pathogen is an urgent priority. Rapid detection will be the key to success. This review summarizes recent progress in the development of rapid real-time PCR protocols and evaluates their effectiveness in a proposed nationwide network of diagnostic laboratories that will facilitate rapid diagnostics and improved communication.

Mitigation of bioterrorist threats in the 21st century

There is a raising level of awareness and concern that agriculture and food supplies might serve as targets for bioterrorists. To minimize such threats a number of new initiates are urgently needed: 1. Greater levels of financial commitment from federal, state, and international organizations for research on highly infectious diseases and for emergency response infrastructure; 2. Wellorchestrated emergency response plans based on inter-agency, inter-departmental and stakeholder working groups; 3. Teams prepared for risk assessment and risk communication; 4. Modern systems of animal identification and accurate trace-back for animal movement; 5. Increased biosecurity in intensive production operations; 6. Accurate intelligence as to what pathogens pose the highest risks for economic and social impact; 7. Establishment of new international animal and plant disease research networks and partnerships; 8. Strengthen international disease surveillance networks for early detection and intervention; 9. New generations of rapid diagnostic tests for pathogen detection that are practical for field and diagnostic laboratories; 10. Increased level of commitment to pathogen genomics research for molecular epidemiology and vaccine development; 11. New chemical and immunological intervention strategies to prevent or control disease outbreaks; 12. Increased level of training on exotic and emerging animal diseases in basic veterinary education and through continuing education for veterinarians, state and federal field personnel and laboratory diagnosticians.