Botulism

I

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.

---

---

II

Types of Botulism

A

Food-Borne Botulism

Botulism can result from eating improperly prepared or handled food products. Most cases of food-borne botulism in the United States involve home-canned vegetables or home-preserved meats. The spores grow best in the absence of air and can thrive in sealed containers that were not adequately sterilized. Commercially prepared foods are now a rare source of this form of the disease.

B

Wound Botulism

Botulism can occur if the Clostridium organism infects wounds from injuries, trauma, or surgery. Cases of wound botulism also have occurred among people injecting illegal drugs.

C

Intestinal Colonization Botulism

The bacterial spores can infect the intestinal tracts of infants and sometimes adults, causing botulism. In infants under one year of age the normal microorganisms found in the intestinal tract may not have developed yet, allowing Clostridium bacteria to colonize. In adults who develop intestinal colonization botulism, the normal microorganisms may have been lost or altered after medical procedures or disease, or use of antibiotics.

	More from Encarta
	•  7 tips for funding an online degree •  How to succeed in the fashion industry without being a top designer •  Presidential Myths Quiz •  Coffee break: Recharge your brain