Botulism is a rare, but very serious condition. It is caused by toxin produced by bacteria called Clostridium botulinum. These toxins are among the most poisonous substances known.

There are four forms of the disease - foodborne, infant intestinal, wound, and adult intestinal. Botulism is always considered a medical emergency. It can cause death by paralyzing the muscles people use to breathe. However, over the past 50 years, the death rate for people with botulism has dropped from 50 percent to 8 percent.

On average, about 110 cases of botulism are reported in the U.S. every year. Botulism is reportable to the Iowa Department of Public Health by Iowa Administrative Code 641/AC 1.


When botulism is caused by contaminated food, symptoms usually appear within 12 to 36 hours. But symptoms can start as soon as six hours later or as long as eight days later.

Symptoms of botulism are the same for all forms and include:

  • Changes in vision
  • Double vision
  • Blurry Vision
  • Drooping eyelids
  • Slurred speech
  • Difficulty swallowing
  • Dry mouth
  • Muscle weakness

Infants with botulism may display symptoms of muscle paralysis caused by the poison. They include:

  • Lethargy
  • Poor appetite
  • Constipation
  • Weak cry
  • Poor muscle tone.

Without treatment, people with botulism may go on to develop paralysis of the arms, legs, trunk, and the muscles used for breathing.


In nature, people can get botulism in three different ways:

  • By eating food contaminated with the poison
  • From the poison produced when a wound is infected with the bacteria
  • When someone eats or drinks something that contains spores of the bacteria

Risk Factors

Most patients hospitalized with botulism are under one year of age. Adults may be more likely to get botulism if they have certain bowel problems.


There is no vaccine available to protect the public against botulism. An experimental vaccine is sometimes used to protect lab workers and military personnel.

You can prevent food-related botulism by using good food-handling practices, especially when canning foods at home. Infants under the age of 12 months should not eat honey, which can contain the bacteria.


The respiratory failure and paralysis that occur with severe botulism may require a patient to be on a breathing machine (ventilator) for weeks or months, plus intensive medical and nursing care. The paralysis slowly improves. Botulism can be treated with an antitoxin which blocks the action of toxin circulating in the blood. Antitoxin for infants is available from the California Department of Public Health, and antitoxin for older children and adults is available through CDC.  If given before paralysis is complete, antitoxin can prevent worsening and shorten recovery time. Physicians may try to remove contaminated food still in the gut by inducing vomiting or by using enemas. Wounds should be treated, usually surgically, to remove the source of the toxin-producing bacteria followed by administration of appropriate antibiotics. Good supportive care in a hospital is the mainstay of therapy for all forms of botulism.


One case of infant botulism was reported in Iowa in 2021.

For more detailed information and statistics on all notifiable diseases, please see our current annual report.

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