BWC UNIVERSALISATION WORKSHOP FOR THE PACIFIC REGION Tanoa International Hotel, Nadi, Fiji 12-13 December 2018
Bioterrorism– A Threat to Plant Biosecurity
In food production systems, plant biosecurity is a state of preparedness that ensures a safe, affordable, and available supply of food and feed. Without effective plant biosecurity programs to protect the world’s staple crops, food safety and security will decline in developing nations and weak governments will fail (Shelburne 2008). This will further compromise global economic development and international programs to reduce hunger and improve health. Without effective plant biosecurity programs to protect the world’s natural plant systems, the ecosystem services that they provide to support humans will decline, thus compromising the development of sustainable societies.
Factors putting plant biosecurity at risk are ◦ global trade of plants and plant products, ◦ climate change, ◦ population growth and landscape exploitation (Stack 2008; Gullino et al. 2008; Brasier 2008). ◦ bioterrorism and biocrime targeting plant systems is the inability to determine that an outbreak was intentionally caused (Fletcher 2008).
Vulnerability of our animal herds and crops through bioterrorism is of concern that needs to be addressed. Animal disease agents including those transmissible to humans (zoonoses) have the potential to be used as biological weapons because they have wide economic and social ranging impacts and are readily available. Inspections and regulatory agencies concerned with food and product safety, and inspections for prohibited products, plants and animals.
difficult to imagine anyone being terrorized by diseased plants. Leaves with spots, rotting tubers, or even corn plants falling over from stalk rot are not likely to send people running. When diseased plants make the news, it is in reference to the economic or ecological damage incurred; disappointment yes, terror no.
Is terrorism involving the intentional release or dissemination of biological agents. ◦ bacteria, ◦ viruses or ◦ Toxins Deliberate release of these agents - cause illness or death of people, animal or plants. Agents are found in nature, however for this purpose, they may be altered or mutated to increase their ability to cause disease, make them resistant to current medicines, or to increase their ability to be spread into the environment
Microbial pathogens were used as potential weapons of war or terrorism from ancient times: ◦ the poisoning of water supplies in the sixth century B.C. with the fungus Calviceps purpurea (rye ergot) by the Assyrians ◦ the hurling of the dead bodies of plague victims over the walls of the city of Kaffa by the Tartar army in 1346 ◦ the spreading of smallpox via contaminated blankets by the British to the native American population loyal to the French in 1767.
Classification of potential biologic threats into three categories: A, B, and C Category A agents are the highest-priority pathogens: ◦ can be easily disseminated or transmitted from person to person ◦ result in high mortality rates ◦ have the potential for major public health impact ◦ might cause public panic and social disruption ◦ require special action for public health preparedness. Category B agents include those that are moderately easy to disseminate, result in moderate morbidity rates and low mortality rates, and require specifically enhanced diagnostic capacity.
Category C agents include emerging pathogens ◦ the general population lacks immunity ◦ could be engineered for mass dissemination in the future because of availability, ease of production, ease of dissemination ◦ The recent emergence of novel viruses leading to outbreaks of severe acute respiratory syndrome (SARS), Nipah, hantavirus are examples
Biologic agents are likely to be used by terrorists as weapons because: ◦ They are capable of damaging populations, economies, and food supplies ◦ Certain agents are inexpensive to make ◦ They can be directed at a small group of people or an entire population ◦ They can be used to attack people, economies and food supplies ◦ They cause fear, panic and social disruption
Anthrax may be the prototypic disease of bioterrorism although rarely spread from person to person U.S. and British government scientists studied anthrax as a biologic weapon beginning approximately at the time of World War II (WWII). Soviet Union in the late 1980s stored hundreds of tons of anthrax spores for potential use as a bioweapon At present there is suspicion that research on anthrax is ongoing by several nations and extremist groups One example of this is the release of anthrax spores by the Aum Shrinrikyo cult in Tokyo in 1993. Fortunately, there were no casualties associated with this episode.
Agroterrorism (or bioterrorism) against plants is conceptually more about why the act might be committed rather than the emotional response of those affected. The most important consideration is the impact from an introduction whether deliberate, accidental, or natural. Bioterrorism is one more threat to consider when developing a strategy for plant biosecurity.
New and emerging diseases have been on the increase recently in many countries. Such diseases as bacterial canker of citrus, high plains virus of corn, sorghum ergot, Karnal bunt of wheat, and scab of wheat are a few examples. Is this increase due to natural causes such as an increase in air travel or international trade, or do deliberate introductions play a role?
Throughout human history, examples exist where the introduction of exotic plant pathogens has caused catastrophic crop losses and tremendous suffering. Most of these examples are unintentional introductions. Intentional introductions can similarly incapacitate a nation's agricultural base by reducing the production of essential foods and negatively impacting the economy, e.g., through embargo of exports.
the intent may be to reduce food production capacity, to render food unpalatable/harmful, to undermine public confidence in food production and food safety systems, and to cause large-scale and sustained economic damage that ultimately lowers a nation’s standard of living. To lower a developed nation’s food production capacity and/or standard of living would likely take a long period of time and be very difficult to accomplish. Most developed nations have adequate to excess capacity to produce food and/or multiple trade agreements to compensate for deficiencies. To lower a developing nation’s food production capacity and/or standard of living could be accomplished in a very short period of time and with relative ease. Many developing nations lack the capacity to produce adequate food and are resource-poor precluding trade to compensate for deficiencies. These nations are very vulnerable to agro- terrorism.
Many agricultural production and distribution systems are open systems with many possible pathways for the intentional introduction of pathogens. Depending upon the pathogen and the plant system targeted, it would be possible to inflict significant economic damage without causing an epidemic. A quarantine pest or pathogen need only be detected to stop shipment of plants or plant products; it does not actually have to cause disease. Another possible objective might be to destabilize international relations by causing sustained disruption of trade among signatories to bilateral and multilateral trade agreements.
Shortages in rice and wheat supplies resulted in bans of exports by several nations (IFPRI 2005; Shelburne 2008). Disagreements over trade can create tension between nations. The intentional introduction of a pathogen to reduce the production capacity upon which a trade agreement is based, or a quarantine pathogen to disrupt a trade agreement, could strain international relations and strategic alliances.
Historical Perspective Several nations developed the technologies necessary for the large-scale production and deployment of plant pathogens (Rogers et al. 1999; Suffert 2003; Madden and Wheelis 2003). The Brazilian Cocoa Case Approximately 20 years ago, the intentional introduction of the witches broom pathogen ( Crinipellis perniciosa (Stahel) Singer) into cocoa plantations in the Bahia region of Brazil was alleged by cocoa producers in the affected area (Homewood 1991, Junior 2006).
Cocoa branches with disease symptoms were reported to have been found wired to trees at the outbreak site. Epidemiologists concluded that the natural dispersal of Crinipellis perniciosa spores from the Amazon cocoa production area to the Bahia production area was unlikely. Thousands of trees were ultimately affected reducing cocoa yields by 75% and causing serious economic losses (Bowers et al. 2001). Years later, a man confessed to the act of deliberately introducing the pathogen in order to undermine the local government (Junior 2006).
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