Fact sheet about botulism

What is botulism?

Botulism is a muscle-paralyzing disease caused by a toxin (poison) made by the bacteria (germ) Clostridium botulinum.

There are 3 main types of botulism. All 3 types are uncommon in the United States:

  • Foodborne botulism occurs by eating foods that contain the toxin
  • Infant botulism (also called intestinal botulism) can occur in infants who eat the bacteria, which then can produce the toxin in the infant’s bowel (intestine). Children under 1 year of age may be at risk because they do not have enough normal bacteria in their bowel to prevent this from happening.
  • Wound botulism occurs when a wound is infected with the bacteria, which can release the toxin in the wound

How do people get botulism?

Clostridium botulinum is naturally found in the soil and can live for long periods of time. The bacteria can get into food and under certain circumstances (when there is no oxygen present in the food) produce a toxin. The toxin is destroyed by heat. For foodborne botulism, a person must swallow contaminated food that has not been properly cooked or reheated after the toxin has been produced by the bacteria in the food. For infant botulism, the infant needs to swallow food or soil that contains the bacteria. Certain foods, such as honey, are more likely to be contaminated. For wound botulism to occur, the bacteria need to get into a wound that has the right conditions to allow the bacteria to produce its toxin. Botulism is not spread from person to person.

What are the symptoms of botulism?

Foodborne and wound botulism produce symptoms that affect the nervous system. These symptoms can include blurred or double vision, dry mouth, difficulty swallowing, muscle weakness, muscle paralysis and slurred speech. In some people, the disease causes respiratory paralysis (leaving the person unable to breathe on his own) and may cause death. Infants with botulism often become constipated, stop eating and become “floppy” and sluggish; these symptoms can then be followed by the more severe nervous system symptoms.

How soon do symptoms of botulism appear?

The incubation period is variable, but neurological symptoms of foodborne botulism usually appear within 12-48 hours with a range of 6 hours to 8 days after eating contaminated food. Infant botulism symptoms appear between 3 and 30 days after eating the bacteria. Symptoms appear in wound botulism between 4 and 14 days after exposure to the bacteria.

How is botulism diagnosed?

A doctor may consider the diagnosis if the patient’s food history and physical examination suggest botulism. However, these clues are usually not enough to diagnose botulism. There are other diseases that can appear similar to botulism, and special tests may be needed to exclude these other conditions.

The most direct way to confirm botulism is by testing a stool sample for foodborne or infant botulism or by testing the wound or blood for wound botulism. This is not a routine test and is only done at a few laboratories, so a doctor must make special arrangements for it.

How is botulism treated?

It is a very serious disease and can be deadly if not treated. If the disease is caught early, the person may receive an antitoxin (medicine) that can stop the progression of the illness. In the case of infant botulism, a special medicine called BabyBIG may be used. Most patients receive supportive care during their illness.

Is there a vaccine (shot) for botulism?

There is an experimental vaccine for botulism but no vaccine that has been tested and proven safe for the public.

Where does botulism occur?

It occurs worldwide as individual cases, and as family and general outbreaks.

What foods are commonly associated with botulism?

It is most often associated with home-canned foods that have a low acid content, such as asparagus, green beans, beets and corn.  However, outbreaks of botulism have occurred from more unusual sources such as chopped garlic in oil, canned cheese sauce, carrot juice, improperly handled baked potatoes wrapped in aluminum foil, and home-canned or fermented fish. Honey can contain the bacteria that cause infant botulism, so do not feed honey to children younger than 12 months.

How can botulism be prevented?

Persons who do home canning should follow strict hygiene procedures to reduce contamination of foods.  Oils made with garlic and herbs should be refrigerated.  Potatoes which have been baked while wrapped in aluminum foil should be kept hot until served or refrigerated.  Because high temperatures destroy the botulism toxin, persons who eat home-canned food should consider boiling the food for 10 minutes before eating to ensure safety. Wound botulism can be prevented by promptly seeking medical care for infected wounds and by not using injectable street drugs.


Where can I get more information?

  • Your doctor, nurse or clinic, or your local board of health (listed in the phone book under local government)
  • The Massachusetts Department of Public Health (MDPH), Division of Epidemiology and Immunization at (617) 983-6800 or toll-free at (888) 658-2850, or on the MDPH website
  • The Centers for Disease Control and Prevention (CDC) website

Spanish and Portuguese translations of this fact sheet are available under additional resources.

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