ABSTRACT
Biological weapons come in several varieties and can be listed by their origin of biological agent. Traditionally, the target for biological weapons was humans, but more recently the target has been expanded to include domestic animals and crops. One reason biological toxins are used for biological weapons is that they are far more toxic than man-made toxins. To be a biological weapon there are many factors. High toxicity is one factor. A toxin can be chemically modified to increase the toxicity, and to increase its resistance to drugs and vaccines. Unlike chemical weapon agents, biological agents are broader in variety and origin. Smallpox, caused by Variola major, is an example of a biological agent. Anthrax (Bacillus anthracis) is not common for humans, yet people are afraid because it is considered to be the most ideal candidate for a biological weapon. Botulism is caused by the bacteria Clostridium botulinum, and its toxin is the most toxic substance in the world.
