Author: Erica Cohen, MD; Abigail Olinde, MD

Editor: Ellen Duncan, MD PhD; Silas Smith, MD

Introduction:

  • Infant botulism is a rare but serious illness caused by ingestion of Clostridium botulinum spores, which then germinate inside an infant’s immature digestive system, producing a potent neurotoxin
  • Botulism affects approximately 75-100 infants nationwide annually, most of whom are under 6 months of age
  • Common Sources of Exposure:
    • Environmental: Botulinum spores are naturally present in soil and dust (particularly in construction sites), making exposure possible in everyday surroundings
    • Honey: In very rare cases, spores can contaminate honey. Therefore, pediatric guidelines strongly recommend avoiding honey in any form to infants under 12 months of age
    • Wounds: Spores can aso germinate in anaerobic wounds or traumatic injuries

Pathophysiology:

  • Clostridium botulinum is an anaerobic, spore-forming, gram-positive bacillus that produces botulinum neurotoxin (BoNT), one of the most potent known toxins
    • Major human disease serotypes: A, B, E, (rarely F)
      • Infant botulism is almost always caused by subtypes A and B
  • Botulinum toxin acts at the presynaptic terminal of peripheral cholinergic synapses by cleaving one or more vesicle or membrane target SNARE proteins, leading to irreversible blockage of presynaptic acetylcholine release and subsequent flaccid paralysis and autonomic dysfunction
    • Different BoNT subtypes bind to different SNARE proteins
      • Type A SNAP-25 (Synaptosomal-Associated Protein, 25kDa)
      • Type B Synaptobrevin (VAMP, vesicle-associated membrane protein)

Clinical Manifestations:

  • Symptoms usually develop gradually over days to weeks and may initially be nonspecific, so early consideration and recognition are crucial

Early Symptoms

Progressive Symptoms

Constipation (often the first sign)

 Generalized weakness or floppiness

Poor feeding or weak sucking

 Drooling

Excessive sleepiness or difficulty waking

 Trouble swallowing

Loss of head control / neck hypotonia

 Reduced facial expressions

Weak crying

 Respiratory failure

Ptosis

 Ophthalmoplegia

Differential Diagnosis:

  • Sepsis
  • Neurologic disorders (e.g., myasthenia gravis, Guillain-Barre syndrome, spinal muscular atrophy, Leigh syndrome, and others)
  • Congenital myopathies
  • Electrolyte imbalances, dehydration/FTT
  • Metabolic disorders
  • Toxic exposures (carbon monoxide, “heavy” metals)
  • Viral illness (e.g., coxsackieviruses, echoviruses, enterovirus, poliovirus, West Nile virus and diphtheria)
  • Hypothyroidism
  • Tick paralysis
  • Stroke

Laboratory Studies:

  • Broad laboratory testing should be obtained in all infants with suspected botulism
  • Lumbar puncture and head imaging may be beneficial based on the patient’s clinical status and concern for other etiologies
  • A stool sample can be used to test for the presence of Clostridium botulinum spores or toxins. NB: stool samples are specific, but not sensitive
  • Confirmatory testing is performed at specialized state public health laboratories and the CDC; therefore, clinicians should reach out to the local or state public health lab as a first point of contact. Secure any food or formula sources for testing.

Management and Disposition:

  • The primary treatment is Botulism Immune Globulin (BIG-IV, BabyBIG), which should be administered if botulism is suspected, even before the definitive diagnosis is made
  • BIG-IV is a specialized antitoxin that neutralizes botulinum toxins A and B to stop the progression and shorten the illness duration
  • Infants with known or suspected botulism require hospitalization, and supportive care should be provided as needed for feeding or respiratory difficulties
  • With prompt treatment, infants generally make a full recovery

How To Access Big-IV:

  • Clinicians should contact the Infant Botulism Treatment and Prevention Program (IBTPP) and the California Department of Public Health (CDPH) IBTPP, the latter of which handles BIG-IV distribution nationwide
    • 24/7 clinical consultation & ordering: (510) 231-7600 — IBTPP on-call physician

Please note: BIG-IV is not active against non-A and non-B botulism, so it is not used for foodborne or wound botulism in older children or adults. In these cases, clinicians should request the heptavalent equine botulinum antitoxin (HBAT/BAT) through public health channels:

  • NYC Health Department 24/7 provider access line: 866-692-3641
  • CDC Clinical Botulism Service 24/7 line: 770-488-7100

Reporting

  • Given the potential for outbreaks, every potential botulism case should be reported to public health authorities.

Recent Relevance:

In November 2025, a multistate outbreak of infant botulism was linked to ByHeart’s powdered “Whole Nutrition” infant formula. Third-party lab testing found Clostridium botulinum in the formula, leading to a nationwide recall. As of early January 2026, there were 51 cases with 0 deaths across 19 states (FDA).

References:

  1. https://www.cdc.gov/botulism/outbreaks-investigations/infant-formula-nov-2025/index.html?utm_source
  2. https://www.cdc.gov/botulism/about/index.html
  3. Cagan E, Peker E, Dogan M, Caksen H. Infant botulism. Eurasian J Med. 2010 Aug;42(2):92-4. doi: 10.5152/eajm.2010.25. PMID: 25610131; PMCID: PMC4261338.
  4. https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-infant-botulism-infant-formula-november-2025