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Introduction

Botulism, potentially fatal illness caused by botulinum toxin, an extremely potent poison produced by Clostridium botulinum bacteria. The bacteria live in low oxygen environments and can contaminate food or open wounds, or can be ingested as spores. The toxin affects the nervous system, blocking signals to the muscles. It is considered the deadliest substance known—less than 1 microgram can kill a human. Without medical care, victims typically die from paralysis that stops the ability to breathe. There are over 100 cases of botulism in the United States every year, with death resulting in under 5 percent of cases.

The Clostridium botulinum organism lives in soil, and exists in different strains that produce slightly different forms of the botulinum toxin. Some strains produce toxins that only cause botulism in nonhuman animals. Other species of Clostridium bacteria have occasionally caused botulism in humans. Another group of Clostridium species can cause gangrene.