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What is botulism?

Botulism is a rare but serious paralytic illness caused by a nerve toxin produced by bacteria called Clostridium botulinum. There are three main kinds of botulism.

  • Foodborne botulism is caused by eating foods that contain the botulinum toxin.
  • Wound botulism is caused by toxin produced by bacteria in an infected wound.
  • Infant botulism is caused by consuming the spore of the bacteria, which then grow in an infant’s intestines and release toxin.

All forms of botulism can be fatal and are considered medical emergencies. Foodborne botulism is a public health emergency because contaminated food may still be available and cause others to get sick.

How is botulism spread?

Naturally occurring botulism is most often spread through eating contaminated foods. However, if botulism were used in bioterrorism, it could either be spread through the air or through contaminated food. It is not spread person to person.

What are the symptoms?

Symptoms include double vision, blurred vision, drooping eyelids, slurred speech, and difficulty swallowing and dry mouth. Muscle weakness which generally starts in the upper body and works its way down also occurs.   People with botulism are usually alert and do not have a fever.

How long does it take for symptoms to appear?

The length of time it takes for symptoms to develop can vary depending on the way a person was exposed and the amount of toxin in the exposure.  For foodborne botulism, symptoms can begin between 6 hours and 2 weeks after exposure, but most commonly begin between 12 and 36 hours.

How is it treated?

Botulism is a very serious disease and can be fatal without medical treatment.  The paralysis and respiratory failure that may occur require a patient to be on a breathing machine (ventilator) for weeks, and to receive intensive medical and nursing care.  If diagnosed early, botulism can be treated with an antitoxin which blocks the action of the toxin circulating in the blood, and can lessen the severity of the illness. In Massachusetts, all cases of suspected botulism are required to be reported immediately to local health departments. In Boston, suspect cases of botulism should be reported to Boston Public Health Commission at 617-534-5611.

How can botulism be prevented?

All canned and preserved foods should be properly processed and prepared. Bulging containers or jars should not be opened and foods with off odors should not be eaten. Recognized sources of infantile botulism such as honey should not be fed to infants.

Boston Public Health Commission
1010 Massachusetts Ave, 6th Floor, Boston, MA 02118.
Phone:(617) 534-5395 Email: