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Clostridium botulinumtoxin: |
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Symptoms and Treatment, Toxicity,
Chemistry, Site of Action, |
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| See also the entry on Clostridium botulinum. | |
| Symptoms, Treatment, Decontamination | |
| Syndrome Name | Botulism |
| Symptoms | A limp paralysis that starts at the head and descends through the body,
affecting both sides of the body. This manifests itself as drooping eyelids
(ptosis), weakness, dizziness, dry mouth and throat, blurred and double
vision, loss of coordination and difficulty breathing.
Despite the severity of the symptoms, the victim remains alert and shows no sign of fever. |
| Onset of Symptoms | Typically 24-36 h after exposure. Very low-level exposure may take several
days to develop symptoms. A rapid onset (<12h) indicates heavy exposure and a poor prognosis. |
| Rapid diagnostic assay | Immunoassay for toxin in body fluids is available but it is likely to
be unhelpful in diagnosis of poisoning via aerosols. |
| Antidote | Antitoxin. Current antitoxins are effective against the three commonest
forms of the toxin and do not cover all 7 known variants.
Pentavalent and heptavalent antitoxins are Investigational New Drugs in the United States. |
| Supportive Care | Artificial respiration to support breathing, tracheostomy may be needed. |
| Prophylaxis | Vaccines using a toxoid (inactivated toxin) are available. |
| Inactivation | Treatment with formaldehyde or hypochlorite bleach. The toxin is heat sensitive and boiling of contaminated objects for 10 mins. can be used. Soap and water are also effective |
| Route | LD50 |
|---|---|
| Intravenous (mouse) | 0.0003 micrograms/kg |
| Inhalation (human) | 0.02 mg/min/m3 |
| Structure | A very large protein that has two
subunits in its mature form. There are seven known subtypes (A-G) of the toxin.
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| CA Name | Botulin Click here to find out why botulin does't have a chemical name. |
| Trivial Names |
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| Registry Number | 107231-12-9 |
| RTECS Number | |
| Molecular Formula | Not applicable |
| Molecular weight | Approx. 150,000 |
| Solubility | Soluble in water |
| pKa in water | |
| Complete synthesis | Chemical synthesis is impractical.
Toxin can be manufactured by fermentation |
At the molecular level, the toxin enters the nerve by binding to a protein on the surface of the cell. Each of the toxin subtypes binds to a different protein. It prevents the release of acetylcholine by blocking the interaction between the synaptic vesicles (the structures within which acetylcholine is stored) and the cell membrane that leads to acetylcholine release and transmission of the impulse. The toxin acts as an enzyme, a protease, that breaks down the protein complex that the vesicle binds to.
The toxins catalytic action means that it may take only one or two molecules to completely inactivate a nerve ending. In comparison, a toxin that simply blocked the interaction would require several hundred or thousand molecules per cell to be effective.
The toxin was considered for use as a weapon by Britain and Japan during the 1930's and there are suggestions that it was used by the Japanese to poison streams used as water sources by the Soviets. It has also been suggested that either the microorganism or the toxin were incorporated into grenades used in the assasination of the Reinhard Gehlen, Hitler's likely successor and Reichsprotektor of Czechoslovakia.
| Disease | ICD-9-CM | ICD-10 |
|---|---|---|
| Botulism | 005.1 | A05.1 |
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