Biodefense refers to measures to restore biosecurity to a group of organisms who are, or may be, subject to biological threats or infectious diseases. Biodefense is frequently discussed in the context of biowar or bioterrorism, and is generally considered a military or emergency response term.Biological Warfare agents are microorganisms like virus, bacteria, fungi, protozoa or toxins produced by them, that give rise to diseases in man, animals or plants, when deliberately dispersed in an area  These agents can cause large-scale mortality, morbidity and can incapacitate a large number of people in the shortest possible time and have adverse effects on human health. The use of biological warfare (BW) agents can be covert or overt and they differ from conventional weapons by way of several unique properties. The effects of these agents are not instantaneous and require few hours to weeks before the symptoms appear in the affected population. It is important to note that all of the classical and modern biological weapons organisms are animal diseases, the only exception being smallpox. Thus, in any use of biological weapons, it is highly likely that animals will become ill either simultaneously with, or perhaps earlier than humans.