What Is Botulism?
Botulism is a rare illness caused by a bacterial toxin that damages the nervous system. The bacteria that produce the toxin are found in many places, such as soil and dust, and usually do not cause disease. For most babies, children, and adults, even consuming the bacterial spores does not cause disease. However, in certain conditions, the bacteria grow from protective spores and produce the deadly toxin. The botulinum toxin affects nerves and causes muscle weakness, including the breathing muscles, which can be fatal.
What Causes Botulism?
Botulism is caused by a toxin produced by Clostridium botulinum bacteria. Other species of Clostridium bacteria can also produce the toxin in certain cases. This type of bacteria forms spores, which are protective coverings that allow them to survive in unfavorable environments. In specific kinds of environments, the bacteria may grow from the spores and produce the damaging toxin.
Conditions that are favorable for toxin production include an environment that is low in oxygen, low in acid, low in salt, low in sugar, and having a certain water content and temperature range. An example of a possible favorable environment for toxin production is home-canned foods.
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What Are the Types of Botulism?
There are different types of botulism. All types of botulism are a life-threatening emergency and should be treated immediately by a physician.
- Foodborne botulism occurs when people consume foods containing the toxin. This most often is the result of improperly canned or preserved foods.
- Wound botulism occurs when bacteria spores that produce the toxin contaminate a wound. This most commonly occurs in people who inject drugs, although it has happened in wounds arising from a traumatic injury.
- Infant botulism occurs when the spores of the Clostridium bacteria get into the intestinal tract of an infant and produce toxin. The consumption of honey and exposure to soil contaminated with the bacteria may cause infant botulism. This usually occurs in infants between 2 and 8 months of age.
- Less common types of botulism include an adult intestinal form of the condition and a condition caused by injection of excessive botulinum toxin (Botox and others) for cosmetic or medical reasons.
What Is the Incubation Period for Botulism?
Symptoms of foodborne botulism usually start 18 to 36 hours after eating the contaminated food. However, signs and symptoms can begin as early as six hours after consumption or may be delayed up to 10 days. Infant botulism related to consumption of contaminated food, such as honey, usually causes symptoms 18 to 36 hours later.
What Are Risk Factors for Botulism?
Risk factors for foodborne botulism include eating home-canned, preserved, or fermented foods that may have been improperly prepared. Drinking some kinds of alcohol made at home may also pose a risk. Specifically, when people make alcohol by fermenting fruit, sugar, water, and other ingredients in plastic bags, this can cause botulism germs to make the toxin. People refer to this kind of alcohol as pruno or prison wine. There have been reports of prison inmates getting botulism from consuming pruno.
Eating certain foods, if improperly prepared or preserved, may pose a greater risk. Examples of foods that have been contaminated in certain cases include chopped garlic in oil, carrot juice, canned tomatoes, fermented fish in Alaska, and baked potatoes wrapped in foil.
What Are Botulism Symptoms and Signs?
Symptoms and signs of botulism reflect the action of the toxin on the nervous system. Symptoms and signs usually begin in the head and neck and include drooping eyelids, blurred vision or double vision, muscle weakness or paralysis, and dry mouth. There is typically a thick-feeling tongue, difficulty swallowing or speaking, and possible difficulty breathing. Nausea and vomiting may be present.
Infants affected by botulism may appear lethargic and "floppy" due to poor muscle tone. They may show poor feeding and a weak cry. Constipation may be the first sign of the condition.
What Tests Do Medical Professionals Use to Diagnose Botulism?
Because the symptoms of botulism can mimic those of other conditions, tests may be necessary to rule out other causes of nerve problems. These can include scans or imaging of the brain, examination of cerebrospinal fluid taken at a lumbar puncture (spinal tap), nerve and muscle function studies, and tests to rule out the presence of a condition known as myasthenia gravis. There are special tests that can look for the presence of the bacteria that cause botulism and the botulinum toxin, but it can take several days for these results to become available. If a medical professional suspects that you have botulism, treatment will begin before these test results are available.
What Is the Treatment for Botulism?
The treatment for botulism involves an antitoxin to counter the effects of the toxin. Hospitalization is required and may be lengthy. The antitoxin will stop future damage but will not cure the damage that has already been done. If a person with botulism has compromised breathing, mechanical ventilation may be necessary.
Medical professionals usually treat infant botulism with an immune globulin (a protein involved with the immune response). Physicians may treat wound botulism with antibiotics; antibiotics are not advisable for the other forms of botulism.
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What Is the Prognosis for Botulism?
With proper treatment, fewer than 5% of people with botulism die of the condition. However, it is fatal without treatment. Some people develop complications such as infections or other problems related to the prolonged paralysis associated with botulism and may have long-lasting effects such as persistent fatigue, speech difficulty, or swallowing problems.
Is It Possible to Prevent Botulism?
It's possible to prevent many cases of foodborne botulism by always adhering to safe home canning and food preservation practices. Infant botulism is harder to prevent. The bacteria can be found in dust and soil, as well as on surfaces inside homes. For almost all healthy individuals, consuming botulism spores is not dangerous and does not cause disease. It is unclear why, in rare cases, some infants develop botulism when the spores get into their digestive tracts and grow to produce toxin.
Honey may contain the Clostridium bacteria that cause botulism. Children younger than 12 months of age should not consume any amount of honey. It is considered safe for people 1 year of age and older.
Reviewed on 2/27/2019
United States. Centers for Disease Control and Prevention. "Botulism." Oct. 4, 2018. <https://www.cdc.gov/botulism/index.html>.