Botulism: Disease Overview, Causes, Signs, Diagnosis, Treatment & Prevention

Some diseases, like botulism, are rare and account for a low mortality. In fact, being a low-prevalence disease explains why there is no defined global mechanism for reporting botulism cases. Regional mechanisms, such as the ECDC, report a case prevalence of 0.02 per 100,000 people.

But being rare and accounting for a few deaths does not make botulism less serious. It also does not lessen the need for caution in observing preventative measures and seeking immediate medical care.

So, what is botulism? What are its symptoms? What are the causes of botulism, and how is it prevented and treated? This post gives you the answers to these questions.

Botulism is a rare but deadly neurological disease caused by the botulinum neurotoxin, a potentially lethal toxin produced by the Clostridium botulinum bacteria. The neurotoxin causes disease by attacking the nervous system tissues.

Following an attack by the botulinum bacteria, a person gradually becomes paralyzed from the head to the face, and consequently, to the trunk and extremities. Delayed botulism diagnosis escalates the situation to respiratory failure and eventually death.
Ironically, the botulinum toxin has medical uses. In fact, the medical form of the botulinum toxin has FDA-approved indications for:

While the Clostridium botulinum spores produce 7 different neurotoxins differentiated by letters A-G, only the A, B, E, and sometimes, F serotypes cause botulism in humans. The other types are recorded in other mammals, and rarely, in fish and birds.

You should also note that, although the bacteria responsible for the botulinum toxin are found naturally in different places, they rarely cause disease.

The botulinum bacteria naturally produce protective spores to be able to survive in any condition. But, in order to thrive and become a threat to people’s health, the bacteria must be under the following conditions:

The above conditions can be met in different food and environmental situations:

Generally, children account for the majority of botulism cases, and foodborne botulism is most common. But is foodborne botulism the only type of botulism?

There are different kinds of botulism, usually categorized by the mode of infection. Keep in mind that botulism is not transmitted from one person to another.

Here are the 6 types of botulism.

Foodborne botulism is a potentially fatal condition that develops when a person ingests food or a drink contaminated by the botulinum toxin. These include:

Once a person ingests the contaminated food, the symptoms of botulism may manifest within 12-72 hours.

Infant botulism is the type that occurs in babies when they ingest the C. botulinum spores, and they produce the toxins in their intestines.

Common causes of infant botulism are ingesting the bacteria in soil and honey. This is why experts advise that you do not feed babies younger than 12 months with honey.

The spores that cause infant botulism are usually slow to germinate in the intestines and will usually manifest in 2-4 weeks.

This type of botulism is rarer and occurs when the botulinum spores find their way into the adult intestines and germinate there, producing the toxins.

Adults with severe gut issues or weak intestines due to previous surgery are more likely to manifest this type.

Depending on the person’s gut health, adult intestinal colonization can take 6 hours to 10 days to present symptoms.

This type of botulism occurs when C. botulinum spores enter an open wound or a skin opening under the right conditions for the development of the botulinum toxin.

Persons at risk include those who inject drugs, those with surgical wounds that take longer to heal, and those with trauma wounds that get dirty with soil.

Wound botulism can manifest within 4-14 days.

​Iatrogenic botulism is related to the medical use of the botulinum toxin. It happens when a person receives improperly prepared, fake, or very high doses of the toxin. It can also occur when unlicensed and untrained persons deliver the toxin incorrectly for cosmetic or treatment purposes.

Depending on the dosage and type of treatment, the signs of Iatrogenic botulism can show immediately or in the period between 1 and 36 days.

While there are no recorded occurrences to date, experts consider Inhalation botulism possible if one breathes in the botulinum toxin. Experts also suggest that it would never happen naturally and would only be possible through an act of bioterrorism.

If it should ever happen, signs of inhalation botulism will appear in 12-36 hours after inhalation.

So, we’ve mentioned that the symptoms of botulism can present within varied timelines depending on the type. But, exactly what are the signs of a botulism infection?

Botulism can have symptoms specific to each type. However, most of the botulism symptoms are general and include:

Infant botulism may have these specific signs:

Important Notes on Botulism Symptoms:

So, apart from noticing these medical signs of botulism, how else do medics diagnose botulism?

Botulism diagnosis happens in multiple stages.

Stage 1: Symptom examination

Diagnosis of botulism heavily relies on clinical suspicion. Once a case is suspected, the clinician performs a thorough physical examination to assess for the symptoms of botulism.

Clinical tools such as the one developed by the CDC (Box 3) can help expedite the diagnosis.

Regardless, a definitive diagnosis can be elusive at this stage because botulism has similar symptoms to other conditions, including myasthenia gravis, stroke, Guillain-Barré, or psychiatric disorders. In the past, botulism has been missed when its symptoms were mistaken for those of these conditions, especially in situations of botulism outbreaks.

Stage 2: Assessment for muscle weakness

In this stage, tests such as Electromyography (EMG), Nerve conduction studies (NCSs), and Repetitive nerve stimulation (RNS) are used to assess the extent of muscle weakness.

These tests look for signs of delayed muscle action or reaction as well as irregular and unsynchronized muscle fiber contraction (fibrillation).

There are several drawbacks to using muscle assessment for botulism diagnosis:

As such, the most reliable method of botulism diagnosis is with laboratory tests.

Stage 3: Laboratory testing for botulism

The Mouse Bioassay is the gold standard method for the laboratory diagnosis of botulism. It is also the only method that’s FDA-approved.

Mouse bioassay involves injecting mouse colonies with suspected samples and observing them for botulism signs or death, an indication of active botulinum toxin.
While the signs may be visible in 24 hours if the toxin level in the specimen is high, lower levels may not show any signs in mice.

Other laboratory methods, such as the highly sensitive Mass Spectrometry (Endopep-MS), can be used to directly detect botulin serotypes A, B, E, & F, but this is only done by the CDC and a few designated public health laboratories.

The Endopep-MS test may follow the notification from reference and non-reference labs when botulism is suspected from physical and muscle assessment or from the results of the non-specific Real-time Polymerase Chain Reaction (PCR) test.

To run laboratory tests, samples can be drawn from the patient’s serum, stool, gastric aspirate, vomit, wound swabs, or suspected food.

Every minute for a botulism patient is crucial, as nerve damage can progress quickly. So, the rule of thumb is to administer botulism treatment as early as possible, even on the basis of physical examination, before lab specimen test results are out.

This is also because lab tests can take several days, during which time the disease continues to cause nerve paralysis and the patient’s life is endangered.

The core treatment for botulism is the administration of botulinum antitoxin. This injection blocks the botulinum toxin from causing further damage.

Note that the Botulism Immune Globulin Intravenous (BabyBIG) is used for infant botulism. And for wound botulism, a debridement wound cleaning procedure is performed with antibiotics to remove the bacteria.

When the disease has progressed to the stage of respiratory difficulty or the onset of respiratory failure, medics put the patient on respiratory ventilation in intensive care.
Botulism recovery is a slow process. So, it can take years of physiotherapy before a botulism patient gets back on their feet. Also, although the botulinum antitoxin does not reverse muscle paralysis, recovery over time can come with the regeneration of new neuromuscular connections for some patients.

So, who’s at risk of botulism?

The following groups of people are at a higher risk for specific types of botulism.

Foodborne Botulism:

Infant Botulism:

Wound Botulism:

Iatrogenic Botulism:

Adult Intestinal Toxemia:

So, how can you prevent the risks?

As you must guess, botulism is highly likely to cause death. It also leaves adverse damage to patients if they survive it. As such, it would not be too much to say that prevention is a million times better than a cure.

So, what measures should be taken to prevent botulism?

Here are some tips to reduce the risk of botulism, according to the different types of the disease.

As a healthcare professional, you should know everything we’ve said so far about botulism. However, you should also take note of some information on botulism that is specific to healthcare professionals, including the following.

The treatment of botulism requires prompt action, from administering the botulinum antitoxin when the disease is confirmed or highly suspected to continuous monitoring of respiratory function and the use of mechanical ventilation, and the delivery of intensive care.

While botulism is not contagious and does not pass from person to person, exposure to an infected specimen can lead to infection.

As such, healthcare professionals should take the following precautions:

Observe handwashing: Wash your hands with soap if you touch body fluids, blood, excretions, secretions, or food that is suspected to be contaminated. This applies whether you were wearing gloves or not. Also, replace the soap with a waterless antiseptic or antimicrobial agent in cases of botulism outbreak control.

Use gloves appropriately: Wear gloves when attending to botulism patients and when handling contaminated specimens or items, and change them when performing different procedures on the same patients. Remove and discard gloves promptly after use, before touching other items or attending to other patients.

Protect your eyes and skin: When attending to a suspected or confirmed botulism case, wear a face mask, eye protection, and a gown to protect yourself from splashes of contaminated blood, secretions, body fluids, and excretions.

Handle patient care equipment professionally: Discard single-use medical items safely and ensure reusable equipment is thoroughly sterilized before using it with another patient to prevent the transfer of botulinum bacteria.

Observe environmental control: Healthcare facility management should ensure their facilities have the required resources for routine disinfection of beds, bedrails, plus other hospital equipment and frequently touched surfaces. Ensure also that these procedures are strictly followed.

Handle patient linen safely: Ensure body fluids, blood, secretions, and excretions do not touch your skin or mucous membranes when you change, transport, or process patient linen.

Isolate patients who are likely to contaminate the environment: Patients who endanger others by vomiting or other ways that might contaminate the environment should be kept in private rooms.

Protect yourself: Handle needles, scalpels, and other sharp equipment with the prescribed care and never perform mouth-to-mouth resuscitation. Instead, use resuscitation bags, mouthpieces, or recommended ventilation devices.

The CDC is the core reference agency for national botulism surveillance. The agency collects data on botulism, analyzes it, and disseminates it to the public and relevant bodies.

The national public health agency also works with other surveillance systems for the distribution of botulism antitoxin, as follows:

Botulism occurs in humans when one is exposed to the botulinum neurotoxin through ingesting the botulinum spores or via wounds and Botox injections.

The toxin makes people sick, manifesting in symptoms such as muscle weakness and paralysis of the head, face, and eventually the trunk and extremities.

There are many types of botulism, including foodborne botulism, infant botulism, and wound botulism.

Diagnosis of botulism is most precise via lab testing of body excretions and secretions, other body fluids, wound specimens, or suspected contaminated food.

Avoid eating food that is poorly preserved, fermented, or canned. For children, desist from giving them honey before they are over one year of age.

The botulinum antitoxin is the only antidote for botulism, used to stop the progression of the disease.

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8. CDC: National Botulism Surveillance.

9. Texas Department of State Health Services: Botulism Standard Precautions.

10. Cleveland Clinic: Botulism (Clostridium Botulinum).