What is botulism?

Spores of Clostridium botulinum bacteria can survive for a very long time in soil or water. If these bacterial spores get into food, or into your intestines or an open wound, they can start to grow and produce toxins. The toxins are poisonous and cause weakness and paralysis. If people become ill from these toxins, that is called botulism.

What forms of botulism are there?

There are 4 forms of botulism:

1. Foodborne botulism is caused by contaminated food. Food can become contaminated if it contains bacteria that produce toxins.
2. Wound botulism happens when the bacteria get into a wound.
3. Infant botulism occurs in babies up to the age of 1 year (usually up to 6 months). This mainly happens if babies eat contaminated honey (especially raw honey) containing spores that grow into bacteria in their intestines.
4. Iatrogenic botulism happens if a person is injected with too much botulinum toxin.  The toxins cause weakness and paralysis. Some people get injections of the toxins, for example to relax wrinkles. This is also known as “Botox treatment”.

What are the symptoms of botulism?

The symptoms of foodborne and wound botulism usually start with:

• nausea
• vomiting
• tiredness
• dizziness
• stomach pain
• dry mouth
• feeling weak

After that, the following symptoms may develop:

• double vision
• blurred vision
• light sensitivity
• problems with swallowing
• problems with speaking
• muscle weakness in arms and legs

Sometimes a person may have problems with breathing because their respiratory muscles are paralysed. Without treatment, people could die of this complication.

What are the symptoms of infant botulism?

Babies who have infant botulism have symptoms that are very similar to other forms of botulism. But before that happens, babies sometimes also have other symptoms, such as:

• constipation
• refusal to eat or drink
• drooling
• high-pitched crying

What are the symptoms of iatrogenic botulism?

If large doses of botulin toxin are injected for cosmetic reasons, it can sometimes leak into other tissues in your body. You may experience muscle weakness around the injection site. In very rare cases, the toxins can enter deeper into the body. If that happens, you could develop the same symptoms that are seen in other forms of botulism.

Who can become very ill from botulism?

Anyone could get botulism, but the risk is very low. Children under 12 months old have a higher risk of botulism, especially infant botulism. The bacterial spores can grow more easily in their intestines, because their own gut flora is not yet fully developed.  Older children and adults never get botulism from eating honey, because their gut flora is well developed and prevents the spores from growing.  

How does botulism spread?

People can get botulism in various ways: from food, by touching dead birds or fish, or from contaminated water or soil. People cannot infect each other.

From food:
The bacteria or bacterial spores could get into food. If the food is not cooked at high temperatures before eating or canning, the bacteria and spores will survive. Under anaerobic (low-oxygen) conditions, such as in a tin or jar, they can start growing again and producing toxins.

Babies under 12 months old could eat bacterial spores, for example in contaminated honey (especially raw honey), and get infant botulism. The spores could grow into bacteria in the baby’s intestines, and produce toxins that make the child ill.

The incubation period between exposure and illness is usually 12 to 72 hours, but can sometimes take as long as 8 days.

From dead animals or contaminated water or soil:
The bacteria or spores could also be present in soil or water, and produce toxins in dead fish or birds (especially waterfowl). The toxins could cause other waterfowl to become paralysed and die.

If contaminated soil or water gets into a wound, the bacteria could grow inside the wound and cause botulism. This is very unlikely to happen.

You could also be exposed by touching dead fish or birds that have active bacteria growing inside them. Never touch dead animals in nature with your bare hands.

If you are exposed through dead fish or birds, the incubation period between exposure and illness is 4 to 14 days.

How can I prevent botulism?

There are various things you can do to prevent botulism:

• Always cook your food thoroughly before eating or canning.
• Do not eat food from tins or jars that are bulging or leaking.
• Do not give honey to babies under 12 months.
• Do not touch dead fish or birds.
• Do not swim in water that contains dead animals.
• Always clean wounds thoroughly.

Is there any treatment for botulism?

Botulism can be treated with antitoxins given through an IV. This needs to happen as soon as possible. The patient needs to be admitted to hospital for treatment. People who are treated quickly often recover fully. It can sometimes take a long time to recover, because the paralysis may linger for a while. A person who has had botulism and recovered fully can still get it again later.

How common is botulism in the Netherlands?

Botulism is found all over the world, but people hardly ever fall ill. Between 2015 and 2024, there were a total of five reported cases of botulism in the Netherlands. There were two reports of foodborne botulism in 2016 and one report in 2022. All three patients had been exposed in the Netherlands, but the exact source was unclear. In 2023, there was one baby aged 8 months with infant botulism. Again, the exact source was unclear.

Botulism is much more common animals, but most forms that affect animals are not harmful to humans. There are various types of botulinum toxins. The toxins that make animals ill do not always affect humans in the same way.