Anthrax is not communicable. Breathing in mucous particles expelled by an infected person cannot spread anthrax because once the spores have transformed into reproducing bacilli in the lymph nodes, they no longer exist as spores in the lungs. They are among the most toxic substances known. Botulism is the clinical syndrome produced by one or more of these toxins. The estimated lethal dose is only 0.001 microgram per kilogram of body weight.
Botulinum toxin kills by interfering with the nervous system, blocking neurotransmissions.
Some chemical warfare agents, like the nerve agents sarin and VX, similarly attack the central nervous system, but botulinum toxin is much more toxic. The progressive muscular weakness is a precursor to sudden respiratory failure. The onset of the disease varies from hours to days after exposure, depending on the dose of the toxin. Laboratory tests are generally of limited value in the diagnosis of botulism. The Gulf War disrupted Saddam Hussein's biological, chemical, ballistic missile, and nuclear weapons programs.