Botulism (or botulism poisoning) is a rare, but very serious illness that can be transmitted through food, contact with contaminated soil, or through an open wound. If not treated early, botulism can lead to paralysis, breathing difficulties and death.
There are three main types of botulism:
- infant botulism
- food-borne botulism
- wound botulism
Botulism poisoning is caused by a toxin that is produced by a type of bacteria called Clostridium botulinum. Although very common, these bacteria can only thrive in conditions where there is no oxygen. Certain food sources such as home-canned foods provide a potent breeding ground.
According to the Centers for Disease Control and Prevention (CDC), about 145 cases of botulism are reported every year in the U.S. Up to 10 percent of those with botulism poisoning can die. (CDC, 2010)
The CDC reports that 65 percent of botulism cases occur in infants or children younger than one year of age. Infant botulism is typically caused by exposure to contaminated soil, or by eating foods that are contaminated by botulism spores. Honey and corn syrup are two examples of foods that can be contaminated. These spores can grow inside the intestinal tract of infants, releasing the botulism toxin. Older children and adults have natural defenses that prevent the bacteria from growing.
Fifteen percent of botulism cases are caused by growth of the botulism toxin in improperly stored food. These can be home-canned foods or commercially canned products that are improperly processed. The World Health Organization (WHO) reports that botulism toxin has been found in:
- preserved vegetables with low acid content, such as beets, spinach, mushrooms, and green beans
- canned tuna fish
- fermented, smoked, and salted fish
- meat products, such as ham, chicken, and sausage (WHO)
Wound botulism makes up 20 percent of all botulism cases, and is caused when botulism spores enter an open wound. Drug use has caused this type of botulism to rise in recent years, as the spores are commonly found in heroin and cocaine. (CDC, 2010)
Botulism is not contagious from person to person. The spores or toxin must be eaten in food or enter a wound to cause the symptoms of botulism poisoning.
Symptoms of botulism can present as soon as six hours or as late as 10 days after the initial infection. On average, symptoms of infant and foodborne botulism begin between 12 to 36 hours after eating contaminated food.
Early signs of infant botulism include:
- difficulty feeding
- drooping eyelids
- weak cry
- loss of head control and floppy movements due to muscle weakness
Signs of foodborne or wound botulism include:
- difficulty swallowing or speaking
- facial weakness on both sides of the face
- blurred vision
- drooping eyelids
- trouble breathing
- nausea, vomiting, and abdominal cramps (only in foodborne botulism)
If you suspect that you or someone you know has botulism, get medical help immediately. Early diagnosis and treatment is crucial for survival.
To diagnose botulism, a doctor will complete a physical exam, noting any signs or symptoms of botulism poisoning. He or she will ask about foods the person ate within the past several days as possible sources of the toxin, and if anyone else ate the same food. He or she will also ask about any wounds.
In infants, a doctor will also check for physical symptoms, and will ask about any foods that the infant may have ingested, such as honey or corn syrup.
Your doctor may also take blood or stool samples to analyze them for the presence of toxins to confirm diagnosis of infant or foodborne botulism. However, results for these tests may take days, so most doctors rely on a clinical observation of symptoms to make a diagnosis.
Some symptoms of botulism can mimic those of other diseases and conditions. Your doctor may order additional test to rule out other conditions or head injuries that may be causing symptoms. These tests may include:
- electromyography (EMG) to evaluate muscle response
- imaging scans to detect any internal damage to the head or brain
- spinal fluid test, which can determine if infection or injury to the brain and/or spinal cord is causing symptoms
For foodborne and wound botulism, an antitoxin is administered as soon as possible after diagnosis. In infants, a treatment called botulism immune globulin is used to block the action of neurotoxin circulating in the blood.
Severe cases of botulism may require the use of a ventilator to help support breathing, and recovery may take weeks or months. Long term therapy and rehabilitation may also be required in severe cases. There is a vaccine for botulism, but it is rarely used as its effectiveness has not been fully tested and there are side effects.
In most cases, botulism is easy to prevent. You can reduce your risk with the following preventative measures:
- Never feed honey or corn syrup to infants younger than one year old.
- Follow proper techniques when canning food at home, ensuring you reach adequate heat and acidic levels.
- Be cautious of any fermented fish or other aquatic game foods.
- Throw away any open or bulging cans of commercially prepared food.
- Oils infused with garlic or herbs should be kept refrigerated.
- Potatoes that have been cooked and wrapped in aluminum foil can create an oxygen-free environment where botulism can thrive. Keep these hot or refrigerate immediately.
- Boiling foods for 10 minutes will destroy botulism toxin.
Written by: Danielle Moores
Medically reviewed by George Krucik, MD