A biological agent (also called bio-agent , biological threat
agent , biological warfare agent , biological weapon , or
bioweapon ) is a bacterium, virus, protozoan, parasite, fungus, or toxin
that can be used purposefully as a weapon in bioterrorism or biological
warfare (BW). In addition to these living or replicating pathogens, toxins and
biotoxins are also included among the bio-agents. More than 1,200 different
kinds of potentially weaponizable bio-agents have been described and studied
to date.