Biological and Chemical Agents

Biological agents* are organisms or toxins that can cause deadly diseases in people, livestock and crops. The agents kill by spreading a disease that may be fatal or by tricking the body's cells into producing a toxin that overwhelms its defenses. Only a small number of the hundreds of bacteria and viruses are viable as terrorist weapons because most cannot survive outside narrow temperature ranges or are too rare and hard to grow. The six main types of biological Category A agents are: