Toxins as biological warfare agents

Abstract Natural toxins or biotoxins are substances produced by one organism that elicit their toxic action on another organism. Toxins are extremely poisonous products of the metabolism of living organisms like bacteria, plants, animals, and fungi. Biotoxins are individual chemical compounds of natural origin. These are biologically active chemical compounds or compounds produced by a specific chemical mechanism in a living organism. Chemically, they are a wide variety of complex structures like proteins, cyclic peptides, alkaloids, etc. After knowing the structure, toxins can be prepared by chemical synthesis in desired quantities. Some toxins can also be prepared by biotechnological procedures like cloning and expression. Toxins, from a pharmacological and toxicological perspective, can be considered chemical weapons. Comparison of physicochemical and functional characteristics place toxins between chemical warfare agents and biological warfare agents. There are several differences between toxins and traditional chemical warfare agents. When compared, toxins have a higher molecular weight, most of them are odorless and not dermally active, and most of them produce immune responses in the host. Toxins are easy to use via inhalation route in the form of aerosols. Their toxicity potential is much higher than highly toxic chemical agents like sarin. As a comparison, the lethal inhalation concentration (LCt50) of a botulinum toxin aerosol, on average, is 1000 times more toxic than sarin vapor. Toxic substances based weapons have a long history of several thousand years. It is associated with traditional methods of hunting, including the use of poisoned arrows, water, or the fumigation of animals with toxic combustion products. All of these hunting forms involving toxic substances were developed for ancient wars. In some form or other, these have persisted until now. Toxins from plants, animals, bacteria, cyanobacteria, algae, and fungi have been used by man for fighting and hunting purposes since the earliest times. Some toxins, such as ricin (W), botulinum toxin (X), or saxitoxin (TZ), were formerly proposed as standard fillings for military ammunition. Intensive military research activity was carried out on some toxins like palytoxin, batrachotoxin, and tetrodotoxin.