Botulinum toxin (Forensic Science)
Although the possibility that botulinum toxin could be used in biological warfare has been acknowledged for many years, no uses of the poison as a weapon have been reported in any major wars. Despite the Biological Weapons Convention of 1972, however, it is generally believed that many countries have stockpiles of the Clostridium botulinum bacterium and toxin as part of their biological warfare programs.
The most common form of botulinum poisoning occurs through the ingestion of foods containing the toxin. Food products contaminated with C. botulinum spores that are stored at room temperature can cause poisoning if they are consumed without first being adequately heated. Canned cheeses, ham, and sausage are common sources of the toxin. In a typical incident that took place in Italy in 1996, eight people contracted the poison by eating commercial cream cheese. One died, and the others had prolonged medical recoveries. In a 1995 incident in Canada, a sixteen-year-old girl was poisoned when she ate smoked fish. She died a few months later despite having received intensive medical treatment. In September, 2006, four cases of botulism in the United States and two cases in Canada were traced to the consumption of contaminated carrot juice.
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Mechanism of Toxicity (Forensic Science)
The toxin, which was first isolated from C. botulinum in 1944 by Edward Schantz, must come into contact with nerve tissue to cause damage. The toxin attaches to the axon terminal of nerve endings, where it blocks the release of the principal neurotransmitter in the body, acetylcholine. This blockage prevents transmission of nerve impulses, resulting in loss of muscle contractility and flaccid paralysis.
In food-related poisoning, symptoms occur six to thirty-six hours after ingestion of food containing the toxin. Symptoms include excessive dry mouth, diarrhea, and vomiting. These may be followed by blurred vision, droopy eyelids, generalized muscle weakness, and progressive difficulty in breathing. Death may occur as a result of paralysis of the respiratory muscles. Symptoms of botulinum poisoning may occur more rapidly if the toxin is inhaled rather than ingested.
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Medical and Cosmetic Uses (Forensic Science)
Some medical treatments have been developed that take advantage of the botulinum toxin’s neuromuscular blocking action; tiny concentrations of the toxin are used, for example, in the treatment of involuntary eye muscle contractions (blepharospasm). The toxin is also used in the treatment of migraine headaches and cervical dystonia, a neuromuscular condition involving the head and neck. Another important medical use of the toxin is in the treatment of excessive underarm perspiration (severe primary axillary hyperhidrosis). The toxin has also been employed at times in the treatment of the following ailments and symptoms, although it is not approved by the U.S. Food and Drug Administration (FDA) for these uses: overactive bladder, anal fissure, stroke, multiple sclerosis, Parkinson’s disease, excessive salivation, neurological complications of diabetes mellitus, and muscle problems affecting the limbs, face, jaw, and vocal cords.
Commercial botulinum toxins, marketed under the names Botox and Dysport, among others, are used cosmetically to remove facial wrinkles and improve facial appearance. The toxin works on wrinkle lines that have been formed in the upper part of the face, particularly the forehead and around the eyes. Because very low concentrations of the toxin are used in these cosmetic preparations, treatment is usually safe. However, occasional adverse effects—such as allergic reactions and paralysis of...
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Investigation of Botulinum Poisoning (Forensic Science)
When deaths or illnesses are suspected to be attributable to botulinum toxin poisoning, both forensic scientists and public health experts are usually involved in investigating the incidents. The immediate goal in any case is to identify the source of the toxin as quickly as possible to prevent any further harm. In the United States, law-enforcement agencies are required to report all cases of such poisoning to the Centers for Disease Control and Prevention (CDC).
Evidence at the suspected poisoning site must be preserved so that it can be analyzed for clues that may point to the source of the toxin. Apart from food, botulinum toxin and the toxin-producing C. botulinum bacterium may be found in the blood and feces of patients suffering from botulinum poisoning. In some fatal cases, forensic examination of tissue samples and suspensions of body fluids have been used to demonstrate the presence of the toxin even after advanced putrefaction.
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Further Reading (Forensic Science)
Balkin, Karen F., ed. Food-Borne Illnesses. San Diego, Calif.: Greenhaven Press, 2004. Collection of essays offers a variety of perspectives on issues of food safety.
Breeze, Roger G., Bruce Budowle, and Steven E. Schutzer, eds. Microbial Forensics. Burlington, Mass.: Elsevier Academic Press, 2005. Details the importance of forensic microbiology and discusses its uses. Includes discussion of botulism.
Scott, Elizabeth, and Paul Sockett. How to Prevent Food Poisoning: A Practical Guide to Safe Cooking, Eating, and Food Handling. Hoboken, N.J.: John Wiley & Sons, 1998. Provides thorough information on the causes and symptoms of food poisoning, including botulism.
Smith, Louis D. S., and Hiroshi Sugiyama. Botulism: The Organism, Its Toxins, the Disease. 2d ed. Springfield, Ill.: Charles C Thomas, 1988. Textbook covers virtually every aspect of botulism.
Tucker, Jonathan B., ed. Toxic Terror: Assessing Terrorist Use of Chemical and Biological Weapons. Cambridge, Mass.: MIT Press, 2000. Collection of case studies discusses various uses of chemical and biological agents by terrorist groups. Identifies terrorists’ patterns of behavior and discusses strategies to combat them.
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Botulinum Toxin (Encyclopedia of Neurological Disorders)
Botulinum toxin is the purified form of a poison created by the bacterium Clostridium botulinum. These bacteria grow in improperly canned food and cause botulism poisoning. Minute amounts of the purified form can be injected into muscles to prevent them from contracting; it is used in this way to treat a wide variety of disorders and cosmetic conditions.
Botulinum toxin was developed to treat strabismus (cross-eye or lazy eye), and was shortly thereafter discovered to be highly effective for many forms of dystonia. Spasticity can also be effectively treated with botulinum toxin. Injected into selected small muscles of the face, it can reduce wrinkling. Other conditions treated with botulinum toxin include:
- back pain
- excess saliva production
- eyelid spasm
- hemifacial spasm
- palatal myoclonus
- spastic bladder
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Botulinum Toxin (World of Forensic Science)
Clostridium botulinum is a spore-forming bacterium. Like the well-known anthrax bacillus, the spores of Clostridium botulinum can persist in the environment for many years and, when conditions become more favorable (i.e., in a wound, food, and the lungs) the spore can germinate and free the toxin.
There are at least seven structurally different versions of botulinum toxin. The type designated as type A is responsible for some botulism food-borne outbreaks in the United States and elsewhere. Improperly canned foods are a particular threat.
Botulinum toxin is among the most poisonous substances known in the natural world. The toxin, which can be ingested or inhaled, and which disrupts transmission of nerve impulses to muscles, is naturally produced by the bacterium Clostridium botulinum. Certain strains of C. baratii and C. butyricum can also be capable of producing the toxin.
Botulinum toxin acts by preventing the transmission of nerve signals between the nerves that connect with muscle cells. Progressive functional deterioration of the affected muscles occurs. Symptoms of botulism intoxication include dizziness, blurred or double vision, nausea, vomiting, diarrhea, and weakness of muscles in various areas of the body. The muscle failure can be so severe as to lead to coma and respiratory arrest. Even in those who survive exposure to the toxin, complete recovery can take months.
The damage and lethality that can be inflicted by the toxin makes this agent important in forensic science. If botulism toxin poisoning is suspected, a
The sometimes deliberate use of the toxin is also forensically relevant. Contamination of food is one route for infection with the toxin. This can occur naturally, via the bacterial contamination of the food. On the other hand, food can be deliberately contaminated. As well, the toxin can also be released into the air. The latter is invariably deliberate. For example, on at least three occasions between 1990 and 1995, while experimenting with biological warfare agents, the Japanese cult Aum Shinrikyo released botulinum toxins, but failed in attempts to spread them.
SEE ALSO Biodetectors; Bioterrorism; Nervous system overview; Pathogens; Toxins.