What Is Botulism? Symptoms, Causes, Diagnosis, Treatment, and Prevention

The most common forms of botulism include:

• Infant botulism
• Foodborne botulism
• Wound botulism

Infant botulism, the most common form, occurs after a baby consumes the bacterial spores, typically by eating contaminated honey. It’s most often diagnosed in babies aged 1 year and younger (infants' digestive systems aren't mature enough to move the botulism-containing honey out of their body quickly).

Foodborne botulism is caused by consuming foods contaminated with the botulinum toxin — most commonly home-canned vegetables, cured pork, smoked or raw fish, honey, and corn syrup.

Wound botulism develops if Clostridium botulinum enters an open wound and releases its toxins.

There are other, even more rare forms of botulism, including iatrogenic botulism. This occurs following an accidental overdose of botulinum toxin during Botox injections, which are used during cosmetic procedures as well as to treat certain neuromuscular disorders.

• Blurred and double vision
• Drooping eyelids
• Slurred speech and difficulty swallowing and breathing
• A thick feeling in the tongue
• Dry mouth
• Muscle weakness

Signs of botulism in infants include:

• Poor feeding
• Lethargy and weakness
• Constipation
• Weak cry
• Poor muscle tone and head control
• Poor gag and sucking reflexes

The signs and symptoms of foodborne botulism typically appear 18 to 36 hours after consuming contaminated food, though they can appear anytime between 6 hours and 10 days after ingestion.

The most common symptoms of foodborne botulism are:

• Problems swallowing, speaking, or breathing
• Dry mouth
• Weakness of the facial muscles
• Double and blurred vision
• Nausea and vomiting
• Abdominal cramps

The signs and symptoms of wound botulism usually appear about 10 days after exposure to the toxin, and they include:

• Problems swallowing, speaking, or breathing
• Weakness of the facial muscles
• Double and blurred vision
• Drooping eyelids

The affected wound may or may not appear red and swollen.

In general, foods with low acid content are the most common sources in these cases, including:

• Carrots
• Corn
• Green beans
• Asparagus
• Beets
• Potatoes

Prepackaged foods and beverages that have been linked with foodborne botulism in the United State include:

• Canned cheese sauce
• Canned tomatoes
• Carrot juice

When an open wound is exposed to Clostridium botulinum, the bacteria can multiply and produce toxins. In recent years, cases of wound botulism have been reported among people who inject heroin, since the drug may be contaminated with spores of the bacteria.

For infants, botulism may be caused by consuming honey contaminated with Clostridium botulinum or exposure to soil contaminated with the bacteria.

In general, people are at risk for botulism if they:

• Inject certain drugs, including black tar heroin
• Drink certain kinds of homemade alcohol, including “pruno” or hooch, which are consumed by incarcerated people
• Eat home-canned or home-fermented foods that haven’t been prepared safely and in clean environments
• Receive botulinum toxin injections for cosmetic reasons (such as for wrinkles) or medical reasons (such as for migraine headaches), as this can cause iatrogenic botulism if it isn’t properly administered

The first step in any botulism diagnosis is a thorough patient history. Your doctor will check you for signs and symptoms, and then ask you about the foods you’ve eaten recently, or if you may have been exposed to the bacteria via an open wound.

For infants with botulism, your doctor may ask if your child has eaten honey recently or if they’ve experienced constipation or lethargy.

In some cases, lab testing of blood, stool (feces), or vomit for evidence of Clostridium botulinum toxin can confirm infant or foodborne botulism. In addition, because the symptoms of botulism are similar to those of conditions such as Guillain-Barré syndrome, stroke, myasthenia gravis, and opioid overdose, your doctor may recommend:

• A brain scan
• A spinal fluid test (lumbar puncture)
• Nerve and muscle function tests

Because these tests can take several days, a medical exam is the best way to diagnose botulism — and, if your doctor suspects you have botulism, you may start treatment immediately.

In general, you should seek medical care immediately if you think you may have botulism, as early treatment increases your chances of survival and lessens your risk of complications.

Prognosis of Botulism

A medication called botulinus antitoxin is used to counteract the bacteria’s paralyzing toxin circulating in the body. If the antitoxin is given before paralysis takes hold, it can prevent worsening symptoms and shorten a person's recovery time.

Medication Options for Botulism

Botulinus antitoxin, which is administered by injection, is the only effective drug treatment for foodborne and wound botulism. The antitoxin works by attaching itself to the Clostridium botulinum toxin that’s still circulating in your bloodstream, preventing it from damaging your nerves.

Treatment with the antitoxin won’t resolve any nerve damage that’s already been caused by the toxin, but your nerves will eventually regenerate on their own during and after treatment.

For wound botulism, your doctor may also recommend antibiotics to help the wound heal and clear up any infection.

For infant botulism, doctors use a different type of antitoxin called botulism immune globulin.

Surgery for Botulism

Surgery is used to treat only wound botulism. In these procedures, surgeons remove the part of the wound in which the Clostridium botulinum toxins are growing.

Prevention of Botulism

There are steps you can take to help prevent most types of botulism.

• Keep foods refrigerated even after cooking.
• Check to see that you’ve cooked food thoroughly prior to eating.
• Avoid prepackaged foods in containers — cans, cartons, or boxes — that are damaged or bulging.

Properly storing and refrigerating foods, ideally within two hours after cooking, prevents the Clostridium botulinum bacteria from producing spores. In addition, cooking food thoroughly can help kill any Clostridium botulinum bacteria.

• Don’t abuse injectable drugs.
• Seek medical treatment for a wound with signs of infection.
• Clean and bandage any open wounds.

Using injectable drugs can expose you to Clostridium botulinum bacteria through contaminated needles.

In general, be sure to properly care for any wounds on your body to lower your risk for infection. Signs of infection include redness, tenderness, swelling, or pus. Proper care includes cleaning wounds contaminated by dirt and soil thoroughly and bandaging them to prevent dirt and bacteria from getting in them.

Wound botulism can also occur after traumatic injuries and surgeries.

The only known way to prevent infant botulism is to avoid feeding babies honey. However, in general, it’s best to take the same precautions designed to prevent foodborne botulism with any meals you prepare for your child.

Botulism can lead to several health complications, mostly related to the muscle paralysis and weakness it causes. These include:

• Difficulty breathing (the most common cause of death in botulism)
• Problems speaking and/or swallowing
• Long-lasting muscle weakness

In 2017, there were 182 laboratory-confirmed cases of botulism in the United States, according to the CDC.

Of these, 141 (77 percent) involved infant botulism, while there were 19 cases each (10 percent) of foodborne and wound botulism. The remaining three were classified as “other.”

The cases of infant botulism were reported in 26 states and the District of Columbia, with California having the most (48). All of the infants were 1 year old or younger, and none of them died.

Foodborne botulism cases were reported in California (15) and Alaska (4), and 15 involved the toxin type A, with 10 traced to nacho cheese sold at a convenience store and 2 to an herbal deer antler tea.

• Lambert-Eaton syndrome, a rare neuromuscular disorder that causes muscle weakness and fatigue, dry mouth, and pain in the thighs and pelvic area
• Guillain-Barré syndrome (or acute idiopathic polyneuritis), a rare, rapidly progressive disorder caused by inflammation of the nerves (polyneuritis) that can lead to paralysis
• Myasthenia gravis, a chronic neuromuscular disease that causes weakness and rapid fatigue of muscles, particularly those that are controlled by the brain stem

Your doctor may take steps to rule out these conditions and confirm a botulism diagnosis.

National Organization for Rare Disorders (NORD)

NORD provides detailed information on rare diseases and disorders, including botulism. While many institutions and organizations overlook these relatively rare conditions, NORD reports on all the latest research, especially new advancements in treatment.

Centers for Disease Control and Prevention (CDC)

The CDC is the definitive resource for information on cases of botulism nationally. The site is a particularly important source for news on outbreaks of foodborne botulism linked with specific products, manufacturers, restaurants, and retailers.

Occupational Safety and Health Administration (OSHA)

OSHA primarily views botulism from the perspective of its potential role as a bioweapon in a terrorist attack. However, the agency also has the latest information on symptom recognition and diagnosis as well as information on any new national outbreaks.

Additional reporting by Brian Dunleavy.