Biological Agents: Threat and Response

Abstract

The vast majority of microbial life is beneficial to human existence, performing functions as diverse as fixing nitrogen for agriculture, degrading toxic materials for bioremediation, and producing natural products which are difficult or impossible to synthesize chemically. In human physiology, bacteria are required for digestion, produce micronutrients in the gut, help to ward off dangerous pathogens, and may be involved in the immune response and healthy cognitive function. In fact, mitochondria, the power-producing organelle in eukaryotic cells, has an independent genome which resembles that of bacteria and is probably an endosymbiotic organelle. Many bacteria are pathogenic to humans and animals via a variety of mechanisms, including the production of toxic chemicals. Viruses, on the other hand, are not technically alive, having no metabolic machinery of their own, and are supramolecular structures which use the host cell’s genome to replicate. Both bacteria and viruses have a long history of causing human disease, either by natural outbreaks or by intentional use by humans. As biological warfare or bioterrorism agents, they have profoundly different attributes from chemical, radiological, nuclear, or kinetic weapons in that their effects are usually delayed, which makes response and attribution difficult – in some cases they are contagious and can spread rapidly through aerosol or physical contact transmission, and there are no medical treatments for many pathogens and toxins. The potential of disease caused by both the deliberate dissemination of biological pathogens and the emergence of new diseases should be viewed as a public health issue to which the tools of risk management are brought to bear. While nature produces, on average, a new major disease every year, advances in synthetic engineering biology now raise the specter of designing de novo new threats for which there are no countermeasures. The possibility of these “biotechnological” agents will require a strategic approach to counter the threat.