Initial symptoms are nausea and diarrhea, followed by weakness, dizziness and respiratory paralysis, often leading to death. Antitoxin can sometimes arrest the process. Iraq's biological weapons were understood to include anthrax bacilli and botulinum toxin. These few were excerpted from a list of several dozen alternatives under study. The ease with which biological weapons can be produced makes it illusive to rely on international agreements, which can be so readily circumvented.
Verification can never be foolproof or effective.
Many experts believe they are a waste of time. One can cultivate trillions of bacteria at relatively little risk to one's self with gear no more sophisticated than a beer fermenter and a protein-based culture, a gas mask, and a plastic overgarment. A large population cannot be protected against a biological attack. Vaccines can prevent some diseases, but unless the causative agent is known in advance, such a safeguard may be worthless. Antibiotics are effective against specific bacteria or classes of biological agents, but not against all.