Botulism is a muscle-paralyzing disease caused by a toxin made by a bacterium called Clostridium botulinum. The Centers for Disease Control and Prevention (CDC) has designated Clostridium botulinum as a Category A bioterrorism threat. According to a June 1999 multidisciplinary panel, Category A agents are considered to pose the greatest threat to US health and security.
Botulism Types
Clostridium botulinum is a gram-positive, spore-forming bacterium found in soil around the world. Cases of botulism are categorized according to the route of transmission.
- Foodborne botulism occurs when a person ingests pre-formed toxin that leads to illness within a few hours to days. Foodborne botulism is a public health emergency because the contaminated food may still be available to other persons besides the patient.
- Infant botulism occurs in a small number of susceptible infants each year who harbor C. botulinum in their intestinal tract or ingest spores.
- Wound botulism occurs when wounds are infected with C. botulinum that secretes the toxin.
- Adult intestinal colonization botulism has recently been described. It occurs in adults with colitis, after bowel surgery, or after significant changes in the normal intestinal bacteria.
Botulism as a Weapon
Botulinum toxin is one of the most toxic substances known to man, more toxic than sarin nerve agent. It is estimated that a single gram of crystallized Botulinum toxin could kill more than one million people. Botulinum toxin could be used to contaminate food supplies, but a more likely scenario involves dissemination of the toxin as an aerosol. During the Gulf War, Iraq produced 20,000 L of botulinum toxin, using 12,000 L for field-testing and to fill warheads. The Aum Shinrikyo cult in Japan and scientists in the former Soviet Union also experimented with botulinum toxin. Despite these efforts, most authorities agree that this toxin would be very difficult to deploy as a weapon of mass destruction because the toxin rapidly degrades in the environment and becomes non-lethal minutes after release.
Botulism Symptoms
With foodborne botulism, symptoms begin within 6 hours to 2 weeks (most commonly between 12 and 36 hours) after eating toxin-containing food. Symptoms of botulism include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, muscle weakness that always descends through the body: first shoulders are affected, then upper arms, lower arms, thighs, calves, etc. Paralysis of breathing muscles can cause a person to stop breathing and die, unless assistance with breathing (mechanical ventilation) is provided.
Botulism Treatment
A supply of antitoxin against botulism is maintained by CDC. The antitoxin is effective in reducing the severity of symptoms if administered early in the course of the disease. Most patients eventually recover after weeks to months of supportive care.
Information for this article was taken from:
- www.cdc.gov Facts about Botulism
- Darling RG, et al - Threats in bioterrorism I: CDC category A agents - Emergency Medicine Clinics of North America; May 2002; vol 20(2).
- Miller JM - Agents of Bioterrorism: Preparing for Bioterrorism at the Community Health Care Level - Infectious Disease Clinics of North America; Dec 2001; vol 15(4).
