Facts About Botulism

Botulism is a rare muscle-paralyzing illness caused by a nerve toxin. Here are some facts about the illness.

What is botulism?

There are three main kinds of botulism. Foodborne botulism is caused by eating foods that contain the botulism toxin,Clostridium botulinum. Wound botulism is caused by toxin produced from a wound infected with Clostridium botulinum. Infant botulism is caused by consuming the spores of the botulinum bacteria, which then grow in the intestines and release toxin. All forms of botulism can be fatal and are considered medical emergencies.

Can Clostridium botulinium be used as a bioweapon?

Botulinum toxin poses a major bioweapons threat because of its extreme potency and lethality; its ease of production, transport and misuse; and the potential need for prolonged intensive care in affected persons.

Have people tried developing the toxin as a bioweapon?

A number of states named by the U.S. State Department as "state sponsors of terrorism" have developed or are developing botulinum toxin as a biological weapon. Members of the Japanese cult, Aum Shinrikyo, tried but failed to use botulinum toxin as a biological weapon.

What kind of germ is Clostridium botulinum?

Clostridium botulinum is the name of a group of bacteria commonly found in soil. These rod-shaped organisms grow best in low oxygen conditions. The bacteria form spores which allow them to survive in a dormant state until exposed to conditions that can support their growth. There are seven types of botulism toxin designated by the letters A through G; only types A, B, E and F cause illness in humans.

Can botulism be spread person to person?

Botulism is not spread person to person.

How common is botulism?

In the United States an average of 110 cases of botulism are reported each year. Of these, approximately 25 percent are foodborne, 72 percent are infant botulism, and the rest are wound botulism. Outbreaks of foodborne botulism involving two or more people occur most years and are usually caused by eating contaminated home-canned foods. The number of cases of foodborne and infant botulism has changed little in recent years, but wound botulism has increased because of the use of black-tar heroin, especially in California.

What are the symptoms of botulism?

The classic symptoms of botulism include double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. Infants with botulism appear lethargic, feed poorly, are constipated, have a weak cry and poor muscle tone. These are all symptoms of the muscle paralysis caused by the bacterial toxin.

If untreated, these symptoms may progress to cause paralysis of the arms, legs, trunk and respiratory muscles. In foodborne botulism, symptoms generally begin 18 to 36 hours after eating a contaminated food, but they can occur as early as six hours or as late as 10 days.

How is botulism diagnosed?

Physicians consider the diagnosis if the patient's history and physical examination suggest botulism. However, these clues are usually not enough to allow a diagnosis of botulism. Other diseases such as Guillain-Barré syndrome, stroke, and myasthenia gravis can appear similar to botulism, and special tests may be needed to exclude these other conditions.

The most direct way to confirm the diagnosis is to demonstrate the botulinum toxin in the patient's serum or stool by injecting serum or stool into mice and looking for signs of botulism. The bacteria can also be isolated from the stool of persons with foodborne and infant botulism.

How can botulism be treated?

The respiratory failure and paralysis that occur with severe botulism may require a patient to be on a ventilator for weeks, plus intensive medical and nursing care. After several weeks, the paralysis slowly improves. If diagnosed early, foodborne and wound botulism can be treated with an antitoxin which blocks the action of toxin circulating in the blood. This can prevent patients from worsening, but recovery still takes many weeks.

Physicians may try to remove contaminated food still in the gut by inducing vomiting or by using enemas. Wounds are treated, usually surgically, to remove the source of the toxin-producing bacteria. Currently, antitoxin is not routinely given for treatment of infant botulism.

Are there complications from botulism?

Botulism can result in death due to respiratory failure. However, in the past 50 years the proportion of patients with botulism who die has fallen from about 50 percent to 8 percent. A patient with severe botulism may require a breathing machine as well as intensive medical and nursing care for several months. Patients who survive an episode of botulism poisoning may have fatigue and shortness of breath for years and long-term therapy may be needed to aid recovery.

Are there any medical applications of botulism?

In April 2002, the Federal Food and Drug Administration approved the use of Botox — a highly diluted derivative of Botulinum toxin type A — as a cosmetic treatment to reduce wrinkles. Botox injections, typically given in the forehead, between the eyebrows and at the outside edges of the eyes, reduces wrinkles by temporarily paralyzing muscles.

— Sources: Center for Civilian Biodefense Strategies at Johns Hopkins University, Centers for Disease Control and Prevention.