In the July issue of IE Connections, Tom Anderson of RestCon Environmental developed an excellent overview of the current biological weapons and response mechanisms. The next step is to present information about the future of biowarfare.
What devious concoctions may be developed and used on future battlegrounds or terrorist attacks? What is the future of detection systems? Some of the answers to these questions are pure conjecture but are based on the current state of scientific knowledge.
Our rapidly increasing knowledge of molecular biology and genetic engineering has enabled us to develop new medical treatments and enhance quality of life. Ironically, it is the exploitation of this knowledge that could ultimately enable the "evolution"of new bioweapons by our enemies.
There has been a fundamental shift in the types of microorganisms developed as biological weapons. Historically, bacteria have been the weapons of choice to defeat enemies through introduction of disease or the disruption of food supplies. Basic scientific knowledge and simple, crude fermentation equipment were all that was needed to produce large quantities of these organisms. The use of bacteria as potential bioweapons has become limited, due in part to large-scale development of and access to antibiotics in the post-World War II era.
The research on the development of new bioweapons has now shifted to viruses. Viruses are advantageous because there are fewer pharmaceuticals available that effectively stop their infections. Also, viruses typically have lower infectious doses, meaning that fewer infectious particles are needed to elicit disease. Viruses also have smaller genomes, allowing for easier manipulation and genetic engineering than for bacteria.
Genetic engineering of a virus could lead to the decimation of a population of mice, Australian researchers at the National University in Canberra revealed in the February 2001 Journal of Virology. The scientists set out to develop a biological control method for non-indigenous mouse populations and, through genetically modifying the normally harmless mousepox virus to cause infertility and stop the mice from reproducing.
To accomplish their goal, the researchers added a small gene fragment encoding mouse egg protein into the viral genetic code with the hopes that the mouse´s immune systems would recognize the egg protein as foreign and mount an immune response. The immune system would then also destroy the mouse´s own eggs; effectively sterilizing them. In order to help jump-start the immune system, the researchers also added genetic code for interleukin-4, a potent inflammatory mediator.
Insertion of the mouse IL-4 gene into the mousepox virus had a dramatic and unintended effect: It actually killed the mice. Because mousepox is closely related to smallpox, it is possible to imagine what would happen if IL-4 were inserted into the smallpox virus and directed on humans. Most mainstream scientists would agree that a hypothetical genetically engineered virus that could kill humans is exactly that 'hypothetical'. Reassuringly, it is not usually as simple as this to engineer a more virulent pathogen.
Blackpox: There are two clinical forms of the smallpox virus, variola major and variola minor. Variola major causes severe disease by producing characteristic large pustules, or "pocks", in the skin, kidneys, lungs, intestines and other organs such as the brain. A rare hemorrhagic form of smallpox causes blistering and bleeding inside the body, in the stomach and intestines and bleed-out occurs similar to what is seen with Ebola virus. The skin appears to shrivel and blacken, hence the name blackpox.
There has been discussion about the existence of a hybrid virus comprised of Ebola and smallpox virus. The popular press has called this Ebolapox, although evidence of its existence has not been substantiated. Ebolapox is, putatively, a genetically engineered cross between the Ebola virus and smallpox that can also be responsible for blackpox.
A former Soviet defector claims that the development of this hybrid has been achieved in his homeland. Accomplishing this task is scientifically unlikely because the Ebola virus is RNA-based while smallpox is DNA-based, but the defector said important disease-causing parts of the Ebola virus were first translated into DNA before they were inserted into the smallpox genome, resulting in a highly contagious and deadly blackpox. Despite the lack of evidence that this hybrid virus even exists, blackpox has been garnering its share of the news because Saddam Hussein purportedly had his hands on this new weapon.
Influenza: Scientists are in the final stages of sequencing the influenza virus responsible for the Spanish flu of 1918. This variant was particularly virulent and responsible for over half a million deaths in the United States and an estimated 20â€”40 million worldwide. Today, it is estimated that influenza kills 20,000 people annually in the United States, although research is now showing this may be closer to 90,000, taking into account coronary heart disease linked to the viral infection.
If the Spanish flu genetic code becomes accessible, then unscrupulous researchers could theoretically reconstruct the deadly virus as a weapon of mass destruction. This is actually not so farfetched because chemically synthesizing an infectious virus from scratch without a natural DNA or RNA template has been demonstrated in poliovirus, a relatively simple RNA-based virus. Fortunately, the ability to synthesize a more complex virus such as influenza through chemical means has not been demonstrated.
Another possible route for exploitation would be to determine the parts of the genetic code of the 1918 variant that were responsible for its high virulence and then add this code to todayâ€™s readily accessible influenza virus.
Genetically based bioweapons: The problem with current bioweapons is the possibility that nontargeted populations may be affected inadvertently.
One has to think twice about releasing bioweapons that have a chance of coming back and killing one´s own people. Genetically based bioweapons (which are also genetically engineered bioweapons) are those that take advantage of differences between races or different ethnicities. To develop these genetically based bioweapons would take an understanding of both the human genome and the difference in the genetic makeup of both your target groups and non-target groups. The differences discovered could be used to engineer current infectious agents to attack only those populations of interest.
The Human Genome Project, whose goal is to sequence the entire human genome, is already near completion. The Human Genome Diversity Project, which began in 1993 to research genetic variation in different populations of humans, is also capable of providing critical information. Its focus is on trying to help understand the genetic basis of disease and resistance and to help those populations that are more susceptible to a particular disease. However, in the wrong hands, this information may be used to help exploit the differences. Researchers still do not fully understand what determines pathogenicity for many infectious agents. This area of research will eventually unlock the key and open up the possibility of exploiting these mechanisms to target specific groups.
Luckily, the advances in molecular technologies will also increase our capabilities for detecting bioagents. A sample of air may contain only tens to hundreds of an infectious bioagent, making it traditionally hard to detect or time consuming. Many researchers are coming up with novel ways to overcome these challenges.
Future biodetectors may include portable, mobile PCR (Polymerase Chain Reaction) devices with micro-array chips. PCR amplifies the small amounts of bioagent DNA into large enough concentrations to react and be detectable on the micro-array chip.
chips contain a library of bioagent DNA probes on their surfaces for hundreds
of known biowarfare agents. Wherever the DNA binds on the chip, a fluorescent
marker lights up revealing the identity of the agent.
Another approach in development uses a system similar to our own immune system. When a bioagent gets inside our bodies, our immune system reacts by creating antibodies that bind to the agent. New biodetectors can take advantage of the fact that the antibody generated is very specific and will bind to that bioagent only. The biodetector may contain hundreds of antibodies to known bioagents. When an agent is sampled, it will bind to the antibody, which will then fluoresce and be detectable.
A unique approach is being developed at the Biosensor Technologies Group at the Massachusetts Institute of Technologys Lincoln Laboratory in Cambridge. They actually use living mammalian tissue cells to detect bioagents. The technology has another advantage as it works with toxins as well. The process uses the immune system´s B cells because they carry antibodies on their surface. These cells are genetically engineered with genes from jellyfish in order to let them glow when a foreign bioagent is encountered. The researchers were able to get detection in as fast as 15 seconds. The biggest obstacle associated with this technology is trying to keep these cells alive in the biodetector, which is not an easy task.
A more realistic approach is taking place that aims at adapting mass spectrometry to work with proteins from bioagents. The mass spectrometer will determine the ratio of amino acids to the molecular weight of protein fragments. This ratio can be searched in a database that uniquely identifies the bacterial species in the original sample. The system is thought to be sensitive down to 100 bacterial cells. The database will be very large, and sophisticated pattern-recognition software will be required to match the identifications. This technology will be limited until the spectrometer is effectively reduced into a portable unit.
The future of bioweapons will invariably change in focus over time. However, it is clear that our scientific advances could be exploited by unscrupulous people to develop new, stealthy bioweapons of mass destruction. Still, the weak link in the development of weaponized microorganisms is, and has been, delivery.
Outbreaks of infectious disease tend to be localized and confinable. Although the technology to engineer novel bioagents is no longer the stuff of science fiction, there are fortunately still many barriers to the development of´a biological agent capable of widespread destruction.
is critical that new technologies be developed for the detection of these biological
agents keeping in mind that the bioagent may be novel. The actual risk to us
now is fear rather than casualties.
Questions? - please contact Jason Dobranic, PhD at: 800-220-3675.