About Botulism

What Is Botulism?

Botulism is a rare but serious illness caused by a toxin that attacks the body's nerves. It can lead to difficulty breathing, muscle paralysis, and even death. The illness is primarily caused by the bacteria Clostridium botulinum [klos-TRID-ee-um bot-yoo-LYE-num], but can also be caused by other strains of bacteria. These bacteria produce toxins called botulinum neurotoxins (BoNT) that harm the nervous system. Botulism can occur through various means, including consuming contaminated food, inhaling the toxins, or through wounds or injection drug use. In the U.S., infant botulism is typically the most commonly reported form, while foodborne botulism is a major/common recognized form but not necessarily the most common overall.

It is important to seek immediate medical attention if you or someone you know shows symptoms of botulism, as it is a medical emergency.

Types of Botulism

Botulism can happen in different ways, depending on how the toxin or bacteria enter the body. The main types are foodborne botulism, wound botulism, and infant botulism. Less common types include iatrogenic botulism, which can occur after too much botulinum toxin is used during a medical or cosmetic procedure, and adult intestinal toxemia, which happens when bacteria grow in the intestines and produce toxin there.

Botulism Causes and Risk Factors

Botulism is caused by powerful toxins made by certain bacteria, most often Clostridium botulinum. These toxins affect the nerves and can lead to muscle weakness or paralysis.

Botulism can happen when the toxin is eaten, when bacteria enter a wound and make toxin there, or when spores grow in an infant’s intestines. The risk depends on the type of exposure.

Common causes and risk factors include:

• Eating improperly canned, preserved, or fermented foods, especially low-acid home-canned foods such as vegetables, fruits, fish, or meats.
• Having a cut, wound, or injection site that becomes contaminated with bacteria that can produce botulinum toxin.
• Exposure to soil or dust that contains bacterial spores. This is most relevant for infant botulism and wound botulism.

You can lower the risk of botulism by:

• Following safe home-canning instructions, including using a pressure canner when recommended for the type of food.
• Heating home-canned foods as directed before eating them.
• Throwing away canned or preserved foods if the container is leaking, bulging, damaged, or smells unusual.
• Refrigerating canned foods after opening and discarding leftovers within the recommended time.
• Keeping cuts and wounds clean and getting medical care for wounds that show signs of infection.
• Not giving honey to children younger than 1 year old.

Botulism Symptoms

Botulism symptoms happen because the toxin affects the nerves and causes muscle weakness. Symptoms often start in the face, eyes, mouth, or throat and can spread downward to the neck, arms, trunk, and legs.

• Blurred or double vision
• Drooping eyelids or trouble moving the eyes
• Dry mouth
• Slurred speech, hoarse voice, or trouble speaking
• Difficulty swallowing
• Weakness in the face, neck, arms, trunk, or legs
• Facial drooping or reduced facial expression
• Shortness of breath or trouble breathing
• Nausea, vomiting, stomach pain or cramps, diarrhea, or constipation, especially with foodborne botulism

In infants, signs may include constipation, poor feeding, weak sucking, a weak cry, drooping eyelids, a “floppy” body, or trouble breathing.

Symptoms can range from mild to severe, and not everyone with botulism has every symptom. Botulism is a medical emergency. If you think you or your child may have botulism, seek medical care right away or go to the emergency room.

How Botulism Is Diagnosed

Botulism is usually suspected based on symptoms, a physical exam, and possible exposure to the toxin. Because botulism can become life-threatening quickly, treatment may begin before lab results are available.

• Medical history and symptom review: A healthcare provider will ask about symptoms such as blurred or double vision, drooping eyelids, trouble speaking or swallowing, weakness, and breathing problems. They may also ask about recent foods, home-canned or preserved foods, wounds, injections, or possible exposure to contaminated soil or dust.
• Physical and neurologic exam: The provider will look for signs of nerve and muscle involvement, such as drooping eyelids, weak facial muscles, a weak voice, difficulty swallowing, or weakness that spreads downward through the body.
• Lab testing: Tests may be done on blood, stool, stomach contents, wound samples, or suspected food to look for botulinum toxin or the bacteria that produce it. These tests can help confirm the diagnosis, but results may take time.
• Tests to rule out other conditions: Depending on the symptoms, a provider may order imaging tests, nerve or muscle tests, or other lab work to check for conditions that can look similar to botulism, such as stroke, Guillain-Barré syndrome, or myasthenia gravis.

Suspected botulism is a medical emergency. If a healthcare provider thinks botulism is possible, they should contact the local or state health department right away to arrange expert consultation and antitoxin release. This often happens before lab confirmation.

If foodborne botulism is suspected, public health officials may also need to identify and test the food source and check whether other people who ate the same food are at risk.

Botulism Treatment Options

Botulism is a medical emergency and usually requires care in a hospital. Treatment focuses on stopping the toxin from causing more nerve damage, supporting breathing and other body functions, and helping the person recover strength over time.

• Antitoxin: Antitoxin is the main treatment for many types of botulism. It helps stop toxin that is still circulating in the body from causing more harm. Antitoxin works best when given early, but it cannot reverse nerve damage that has already happened.
• Breathing support: If botulism weakens the muscles used for breathing, a person may need oxygen, close monitoring, or a ventilator until they can breathe on their own.
• Hospital care: Many people need medical and nursing care to monitor swallowing, breathing, hydration, nutrition, and complications while the toxin’s effects slowly wear off.

For wound botulism, treatment may also include surgery to remove infected tissue and antibiotics to treat the wound infection. Antibiotics are not used to treat all forms of botulism, so treatment depends on the type and cause.

Recovery from botulism can take weeks to months. Some people need rehabilitation to rebuild strength and improve functions affected by muscle weakness, including:

• Speech therapy
• Swallowing therapy
• Physical therapy
• Occupational therapy

The exact treatment plan depends on the type of botulism, how severe the symptoms are, and whether breathing, swallowing, or wound care support is needed.