Botulism

Medically Reviewed by Jabeen Begum, MD on March 29, 2024
Written by Kristin Mitchell, WebMD Editorial Contributor
10 min read

Botulism is a serious but rare condition that attacks your body's nerves. Botulism is caused by the bacteria Clostridium botulinum (C. botulinum). It releases a neurotoxin, which is a poison that attacks your nervous system. 

Of the many types of foodborne illnesses, botulism is one of the most dangerous. It can paralyze you and can be life-threatening.

 

One way you can get the toxin in your system is by eating tainted food. But there are other ways for you to get it as well:

Infant botulism

 Babies can take in spores from Clostridium botulinum bacteria and get this type of botulism. This bacteria is commonly found in dust and soil and can get on floors and carpets. When the soil and dust become airborne, your baby can breathe in the bacteria's spores.

Infant botulism can also happen if your baby eats honey, where the spores can also be found. As children get older, they build defenses in their intestines to keep the spores from taking root.

This type of botulism typically affects babies who are younger than 6 months old, however babies are at risk for botulism until they're 1 year old.

Wound botulism

Botulinum spores can get into open wounds and slowly reproduce, eventually releasing the toxin and attacking the nerves in your body. Wound botulism can make it hard to breathe, cause weakness in your muscles, and can even lead to death. People who inject illegal drugs, like black tar heroin, into their skin or into their muscle are at risk of this type of botulism. Those who have trauma, like surgery or a vehicle accident, can get wound botulism too. 

Inhalation botulism

Inhalation botulism happens when you breathe in the bacteria from an aerosol source, or a substance that's under pressure and is released into the air in the form of a spray. The release can be by accident or on purpose, such as during acts of bioterrorism (releasing toxins in the form of bacteria, viruses, etc. on purpose). Breathing in the toxin is rare, though some nations have tried to make biological weapons that would spread a deadly form of the toxin into the air.

Adult intestinal toxemia

This very rare kind of botulism is similar to infant botulism. Bacteria spores get into your intestines, where they grow and spread. It’s also called adult intestinal colonization. Adults with serious health conditions of the gut are most at risk.

Iatrogenic botulism

You can get this form of botulism if you have too much of the Botox toxin injected during a cosmetic or medical procedure; for example, when treating migraines or wrinkles. Some people have had this type of botulism after getting fake Botox treatments.

Botulism is usually caused by a bacteria called Clostridium botulinum. It can also be caused by Clostridium butyricum or Clostridium baratii bacteria. The spores from these bacteria grow under certain conditions, including:

  • Levels of low oxygen or no oxygen
  • Low cooking temperatures
  • Warm storage temperatures
  • Low acid, sugar, or salt
  • A certain amount of water or temperature range

When the bacteria develop, they can release toxins and attach to your nerves. Botulism develops when your nerves aren't working anymore.

 You can get botulism when you incorrectly can, preserve, or ferment foods, like fruits and vegetables , at home. The bacteria or the spores grow in environments that lack oxygen, like food that's not correctly processed. Commercially canned foods can carry the bacteria that cause botulism, but it's not common. It's possible to get botulism in ways besides food poisoning.

No matter how you get botulism, the symptoms are usually the same. The most defining symptom is weakness that starts on both sides of your face, goes down to your neck, and then to the rest of your body. Other early symptoms include:

  • Double or blurred vision
  • Drooping eyelids or trouble moving your eyes
  • A hard time swallowing or breathing
  • Slurred speech
  • Shortness of breath
  • Slower or different eating habits 
  • Constipation
  • Weak muscles

Other symptoms that can follow include vomiting, belly pain, and diarrhea. Later, you may have a very hard time peeing and have severe constipation. Symptoms do not include a fever.

If you don’t get treatment, your symptoms could progress to paralysis of your arms and legs and the muscles used for breathing.

Infants with botulism have symptoms that include:

  • Tiredness
  • Poor muscle tone starting in the head and neck and moving down
  • Poor feeding
  • Drooling
  • A weak cry or less expression in the face
  • Constipation
  • Trouble with breathing
  • A hard time swallowing

Symptoms of wound botulism are similar to those of general botulism but may take about 2 weeks to appear. They also can include:

  • Fever
  • Skin redness, swelling, and other signs of infection

Symptoms of inhalation botulism are the same as those for general botulism but usually happen more quickly. Respiratory failure – when you don't have enough oxygen or too much carbon dioxide – can happen.

Symptoms of adult intestinal toxemia are similar to those of infant botulism. Symptoms are the same as those of general botulism but may also include:

  • Constipation
  • Poor feeding
  • Lack of energy (lethargy)

Symptoms of iatrogenic botulism are the same as those seen in general botulism. Along with muscle weakness, you could have:

  • Eye muscle weakness
  • A hard time speaking
  • A paralyzed face
  • A thick, weak tongue
  • Reduced gag reflex

Foodborne botulism symptoms usually appear within 18 to 36 hours of eating food with the bacteria, though they could show up in as little as 4 hours.

In some cases, symptoms of botulism don’t happen for up to 8 days after exposure.

Infant botulism may not appear for 14 days. A baby with botulism may appear fussy or lethargic, and may be constipated and unwilling to eat.

If you or someone close to you has symptoms that could be signs of botulism, call 911 right away. Respiratory failure – when you don't have enough oxygen or too much carbon dioxide – is a concern, and close monitoring is important.

Botulism can cause severe symptoms, but it cannot be spread from one person to another. However, if you are sick with botulism, you very likely will have to stay in the hospital for monitoring and treatment.

You may have long-term breathing problems if your case is severe. Problems include shortness of breath and being easily tired out.

With proper treatment, you can fully recover from botulism. How fast you get over it depends on how severe your case is. When your case is mild, you may need weeks or months for a full recovery. It may take months or years to completely get over a very serious case.

If the illness isn’t treated, botulism can be life-threatening. But people recover in about 90% to 95% of cases.

Your doctor will likely start with a physical exam, looking for signs of botulism such as muscle weakness, a weak voice, or drooping eyelids. They might also ask you about foods you (or your baby) have eaten.

They may order a lab test to analyze either your blood or a stool sample to confirm their diagnosis. Other tests may be needed.

If you happened to have saved the food you suspect caused the botulism, you can take it in for testing.

Lab tests may take a couple of days. In the meantime, your doctor may try to rule out other possible conditions. Botulism symptoms are similar to those of stroke and Guillain-Barre syndrome, in which your immune system attacks your nerves, causing possible paralysis.

Other tests that may be done to diagnose botulism include:

Brain scan. A magnetic resonance imaging (MRI) or computed tomography (CT) scan of the brain can help rule out other reasons for your symptoms, such as a stroke.

Spinal fluid exam. A cerebrospinal fluid (CSF) study, sometimes called a spinal tap, may show a slight increase in the level of protein. But a CSF study is essentially normal in people with botulism.

Nerve and muscle function tests. Electromyography can help confirm a diagnosis of botulism.

Tensilon test. This is done to rule out myasthenia gravis, which can cause similar symptoms.

If these tests don't confirm whether you have botulism, your doctor may have lab tests done to look for bacteria or toxins.

Your doctor will have you admitted to a hospital, where several treatments may be tried, depending on your case. They include:

Antitoxins. The main treatment for botulism is a medication called an antitoxin. It interferes with the toxin in your bloodstream. This medication can often help stop symptoms from getting worse.

Antibiotics. Sometimes these may work if your case is wound botulism. These bacteria-killing medications aren’t used for other types of botulism.

Breathing aid. If your case of botulism has seriously affected your muscles for breathing, you may need to be hooked up to a machine that helps you breathe. You may be on a mechanical ventilation machine for months if the illness is severe.

Therapy. You may need programs to help with your speech, swallowing, and other body functions as you start to get better.

Botulism incubation period

The incubation period for foodborne botulism, or the time it takes for the condition to develop after being exposed to the toxin, is 12-36 hours; but it can be as early as 6 days and as late as 10 days after taking in the toxin.

With infant and inhalation botulism, it's hard to tell the exact time of exposure.

 

If you can your own food at home, make sure your hands, containers, and utensils are as clean as possible. Clean and store food carefully to lower the chance of tainting the food you’re canning.

The botulism toxin can be killed at high temperatures, so if you’re eating home-canned food, consider boiling it for 10 minutes to kill the bacteria. Proper refrigeration can help prevent the growth of C. botulinum, too.

Here are a few telltale signs of possible botulism contamination in canned foods:

  • The can has a bulge.
  • The container spurts out foam or liquid when you open it.
  • The contents smell unusual or foul.

If you ever see a bulge pushing out from a can or container, do not open it. Throw it away. If there is something wrong about the way food smells, don’t even taste it.

A couple of other things to remember:

  • Store oils infused with herbs or garlic in a refrigerator.
  • Potatoes cooked and wrapped in aluminum foil create an environment where botulism toxins can thrive. Always keep the potatoes hot or store them in a refrigerator within 2 hours of cooking.
  • Boiling foods for at least 5 minutes can destroy the botulism toxin.
  • Don’t give honey or corn syrup to a baby younger than 1 year old.
  • If you’re addicted to heroin, never share needles and don’t use black tar heroin. Seek out a doctor to help you with your addiction.

 

Botulism spores can be found in honey, and if your infant eats honey, the spores can grow in their digestive tract. Older children and adults aren't affected by the spores, as their digestive systems are more developed and the toxins are able to move through their systems before they become harmful.

Garlic is considered a low-acid vegetable that can support the growth of the bacteria if left in conditions that have no oxygen, moisture, or at room temperature. Garlic in oil mixtures and canned versions of garlic can lead to botulism if they're improperly stored, canned, or prepared.

With garlic in oil specifically, recent research has shown the mixtures can be prone to botulism if left at room temperature. According to the U.S. Department of Agriculture, garlic in oil should be fresh and stored in the refrigerator at no lower than 40 F and used within 7 days. Another option is to freeze the mixture in plastic or glass freezer containers with some headspace, which can help it to last up to several months.

Botulism is a serious but rare condition caused by a few types of bacteria, most commonly Clostridium botulinum, that attack your nervous system and can lead to muscle weakness and becoming paralyzed. The spores from the bacteria can be breathed in, can get into open wounds, injected, or taken in from certain food sources.  Taking extra care when preparing, canning, and preserving foods at home can prevent botulism. Also, keeping honey out of your child's diet until after they turn 1 year old can protect them from infant botulism. Seek care right away if you or your child has any symptoms of botulism. Immediate treatment is important for effective treatment.

  • How can you tell if botulism is present? You're not able to tell if a food has the botulism bacteria in it by how it looks, tastes, or smells. But if a canned or preserved container is damaged, leaking, or swollen on the outside, or when you open it it has a bad smell, looks moldy, or causes liquid to squirt out, it may be contaminated and should be thrown away. Even a small taste of a food that contains the bacteria can be deadly.
  • What foods carry botulism? Botulism can be found in honey and in garlic that's in oil mixtures. It is also common in foods with low acid levels, including meat, seafood, and some fruits and vegetables, including figs, potatoes, corn, and green beans. Other foodborne sources of botulism are oils with herbs, carrot juice, canned cheese, canned tomatoes, and certain foods left out of the refrigerator.
  • What kills botulism? The bacteria's spores can be killed when in very high temperatures, such as conditions during commercial canning processes (for example, vacuum packing). But this still may not kill all of the spores, so preventing the growth is very important.