Bioterrorism refers to the exploitation of biological toxins or pathogenic organisms to produce disease and death in humans with the aim of spreading terror and fear in the society. It is worth noting that currently bioterrorism agents are fundamentally naturally occurring pathogens that have been genetically altered to make them resistance to drugs and available vaccines. These organisms have also been altered to augment their virulence or make their propagation spreading easier and rapid without earlier detection. Centre for Disease control (2000) points out that bioterrorism is not a new phenomenon in the human history since as earlier as the 6th century BC the Assyrians did poison the wells of their enemies using a virulence fungus named rye ergot. Around the same period, the Romans utilized corpses of diseased animals for the same purpose. While invading the city of Kaffa (currently the Ukrainian city of Feodosiya) in the 14th, the Mongols (Tartars) catapulted corpses and other bodies of the dying plague victims into the city resulting in unanticipated spread of the plague beyond the walls of the city and was thought to be responsible for the ‘Black Death’ or bubonic plague that shook Europe in the Middle Ages. However, the primary aim of this paper is to analyse the current approaches employed in the detection of pathogenic agents hence prevent or timely respond to a bioterrorism attack.
Unlike ancient attacks, the current technological developments have made biological agents more dangerous than ever. According to Wheelis (2007) the fact that both biotechnology experts and equipments are readily available anywhere in the globe has made bioterrorism more imminent than ever. Other factors that have made bioterrorism more imminent are the numerous international conflicts that forced many countries to research and stockpile biological weapons, including Germany, United States, Russia, Japan and Iraq. However, the good news is that most of these weapons have been destroyed as a result of the agreement of the 1972 Geneva Convention on the Prohibition of the Production, Development and Stockpiling of Toxin and Bacteriological Weapons and on their Destruction (Centre for Disease Control, 2000). Despite this good news there are concerns that terrorist groups and rogue nations like Iran and North Korea might acquire this technology and hence carry out a bioterrorist attack. These fears have been reinforced by the recent attacks using biological agents in various parts of the world including the 2001 spreading of Bacillus anthracis via the Postal Service of the United States. Due to the renewed threat of a potential bioterrorist attack various government around the globe have developed rapid pathogen detection methods as a bioterrorism response mechanism.
Wheelis (2007) states that current the United States and other developed countries uses a combination of technology and instrument or platform that span the spectrum of platforms and technologies employed in environmental and clinical microbial detection or testing which have been shown to be reproducible, specific, sensitive and rapid. It is worth noting that most of these programs in the US are funded by the United States federal government as its war against terrorism and being undertaken by agencies of the government including CDC, FDA, Department of defence and other private agencies. The combination has also been found to have the ability identifying and detecting agents in complex industrial, clinical and environmental samples. Combinations of the current procedures have the ability to detect agents that have undergone antigenic, chemical, genetic modifications in addition to the ability of detecting the unusual variants of classic pathogens. But Centre for Disease control (2000) points out that despite the development of the novel rapid detection procedures, routine culture, staining as well as biochemical typing, both automated and manual, are still the gold standard for identification and detection of bioterrorism agents. But the major weakness of these procedures is their speed as most of them days to detect the agents and most of them are not versatile enough to detect modified or new forms of the typical agent. This has called for the introduction or inclusion of molecular and immunological procedures that are relatively faster.
Majority of the molecular procedures employed currently in the identification and detection of bioterrorism agents are based on quantitative real-time Polymerase Chain Reaction (PCR), which uses taq Enzyme, agent specific primers and probes. Some of the currently employed probes include molecular beacons, taq man probes, scorpion probes, dual FRET probes and other sophisticated instruments (Wheelis, 2007). For instance the air in the United States is currently monitored by approximately 30 undisclosed cities by the so called BioWatch program, a program that employs air samples to test for chemical and biological threat agents days and night throughout the year in the designated cities. This technology employs PCR-based procedures due to its rapidity as well as sensitivity in detection of nucleic acids. Various technologies have been employed in order to make these systems portable, small and rugged to facilitate their application in the field in swift response to any threat.
Another rapid approach currently in use is the PCR and 16S rDNA gene sequencing. In this procedure the sequence obtained is employed to query GenBank in addition to other databases for the sequence that best matches the sequence obtained via the above procedure. Wheelis (2007) points out that this procedure has the ability of rapidly detecting as well as identifying the agents to their strain level. Despite its rapidness and versatility, this procedure sometimes fails to discriminate between some strains of a specific species. For instance majority of B. Anthracis strains have similar 16S rDNA sequence hence cannot be differentiated using this procedure. Numerous procedures are under evaluation and development e.g. multiplex PCR microarray assays for the identification of multiple pathogens in a single reaction (Wheelis, 2007).
The growing threat of an imminent bioterrorism attack against the United States and its allies as well as the associated detrimental consequences necessitates the development of reliable, versatile and rapid pathogen detection procedures as the fast and most effective line of defence against such attacks. Earlier detection and identification of a bioterrorism agent will enable authorities around the world to put in place effective mechanism to evade a human catastrophe.
References
Centre for Disease control. (2000).Biological and Chemical Terrorism: Strategic Plan for preparedness and response.
Wheelis, M. (2007). Biological and toxin weapons. Stockholm: Macmillan Publishers.